I. Executive Summary

A. Needs

B. A Grand Challenge

C. The Present Opportunity

D. The Importance of Catalysis Science

II\. Introduction

A. Workshop Background

B. Recent Scientific Advances

i\. Capabilities

ii\. Needs

iii\. Challenge

C. A Grand Challenge

D. Enabling Sciences

i\. Unifying Sub-disciplines

ii\. Educating a New Generation

E. Consensus Observations and Recommendations

i\. Catalysis - an essential science for society

ii\. reached a juncture to move into multidisciplinary approaches

F. Opportunities for the Department of Energy

i\. Chemical Bonds -- the major source of energy

ii\. BES the major Federal source

G. Summary of Specific Challenges and Opportunities

III\. Opportunities of Scientific Advances

A. Catalysis and Nanoscience

i\. Electronic Structure

ii\. Synthesis

iii\. Characterization

B. Merging Homogeneous and Heterogeneous Catalysis

i\. A new era in Building molecular catalysts

ii\. A new era in building nanostructures

iii\. new capabilities in theory and modeling

C. Biocatalysis

i\. new enzymes

ii\. optimizing biocatalysts through evolution

iii\. integrating Biological and Chemical Catalysis

D. Tools for the 21^st^ century

i\. Synthesis and Characterization -- needs and opportunities

a\. new paradiums

b\. new tools

c\. new understanding

d\. prospect for success

e\. new characterization requirements

ii\. Theory and Modeling -- needs and opportunities

a.  integrating electronics, structures, pathways and energetics

b.  new methods to bridge temporal and special gaps

c.  database analysis

d.  discipline independent tools

IV\. Integration -- A Strategy for Success

A. Linking Basic Discoveries with Applied Technology

B. National Facilities and Capabilities

C. A National Agenda for the Future (need a better title)

V. Appendix A -- Workshop Agenda

# 

# 

# 

# Executive Summary

Catalysis provides the means of changing the rates at which chemical
bonds are formed and broken and of controlling the yields of desired
products over undesired ones. Catalysis affects our lives in myriad
ways. Chemical catalysis lies at the heart of our quality of life: The
cleaner emissions of modern cars, the abundance of fresh food at our
stores, and our healthier lives from new pharmaceuticals are made
possible by chemical reactions controlled by catalysts. Catalysis is
essential to a healthy economy: The petroleum, chemical, and
pharmaceutical industries, contributors of \$500 billion to the GNP of
the United States, rely on catalysts to produce everything from fuels to
"wonder" drugs to paints to cosmetics. ***Today there are new challenges
facing the Nation in creating alternate fuels, reducing harmful
byproducts in manufacturing, cleaning up the environment and preventing
pollution in the future, dealing with the causes of global warming,
keeping us safe from the release of toxic substances and infectious
agents, and creating safe pharmaceuticals. Catalysis are needed to meet
these challenges, but their complexity and diversity demand a revolution
in the way catalysts are designed and used. This revolution can become
reality by the application of new methods in the synthesis and
characterization of molecular and material systems. The opportunities to
understand and predict how catalysts work at the atomic and nano scales
are presented by breakthroughs in the last decade in computation,
measurement techniques, imaging, and new developments in catalyst design
and synthesis.***

***A Grand Challenge***

On May 14, 15 and 16, 2002, a workshop entitled "Opportunities for
Catalysis Science in the 21st Century" was conducted in Gaithersburg,
Maryland. The impetus for the workshop grew out of a confluence of
factors: the continuing importance of catalysis to the Nation's
productivity and security, particularly in the production and
consumption of energy and the associated environmental consequences, and
the emergence of new research tools and concepts associated with
nanoscience that can revolutionize the design and use of catalysts in
the search for optimal control of chemical transformations. While
research opportunities of an extraordinary variety were identified
during the workshop, a very compelling, unifying and fundamental
challenge became clear. Simply stated, ***the Grand Challenge for
Catalysis Science in the 21st Century is to understand how to design
catalyst structure to control catalytic activity and selectivity.***

***The Present Opportunity***

In his address to the annual meeting of the American Association for the
Advancement of Science, Jack Marburger, the President's Science Advisor,
spoke of our emerging ability to achieve an atom-by-atom understanding
of matter and the subsequent unprecedented ability to design and
construct new materials with properties that are not found in nature.
*"The revolution I am describing,"* he said, *"is one in which the
notion that everything is made of atoms finally becomes operational. ...
We can actually see how the machinery of life functions, atom-by-atom.
We can actually build atomic scale structures that interact with
biological or inorganic systems and alter their functions. We can design
new tiny objects \"from scratch\" that have unprecedented optical,
mechanical, electrical, chemical, or biological properties that address
needs of human society."* Nowhere else can this revolution have such an
immediate payoff as in the area of catalysis. By investing now in new
methods for design, synthesis, characterization and modeling of
catalytic materials, and by employing the new tools of nanoscience, we
will achieve the ability to design and build catalytic materials atom by
atom, molecule by molecule, nano-uint by nano-unit.

The opportunities to understand and predict how catalysts work at a
fundamental level have unfolded dramatically in the past twenty years
with the emergence of powerful predictive methods including density
functional theory; incisive instruments for imaging at the nano and
atomic scales; and dedicated facilities for examining catalysts as they
function, even at the high temperatures and pressures used in industrial
processes. New approaches such as rapid catalyst synthesis and screening
techniques, nanofabrication capabilities, computational methodologies
implemented on multiple terascale computers, and the impending
construction of new nanoscience research centers all converge to place
catalysis on the threshold of new understanding and new technology.

***The Importance of Catalysis Science to DOE***

For the present and foreseeable future, the major source of energy for
the nation is found in chemical bonds. Catalysis affords the means of
changing the rates at which chemical bonds are formed and broken.
Catalysis allows chemistry of extreme specificity, selecting a desired
product over an undesired one. When scientists and engineers understand
how to design catalysts to control catalytic chemistry, the effects on
energy production and use will be profound. When this grand challenge is
met, scientists will produce new catalysts and catalytic processes for
yet unimagined benefits.

###### The Importance of Federal Investment in Catalysis Research

The convergence of new capabilities and deepening needs for advanced
catalysis research has coincided with a regrettable abandonment of
support for catalysis research and development by U.S. industry, along
with a debilitating erosion of governmental support. The U.S. has lost
its former position of world leadership in catalysis and now must
scramble to win it back. Other countries have recognized the tremendous
importance of catalysis science as a key to their economic
sustainability and environmental management, and they are devising
strategies for developing catalysis R&D through joint industry and
university research programs, in many cases through the creation and
funding of multidisciplinary "catalysis institutes". The American way of
conducting research has traditionally been more conducive to innovation
than that of our competitors, and we can and must regain our
unquestioned leadership role. Delaying new investments in these critical
sciences will further erode the U. S. position and increase our
dependence on imported technologies and reliance on international
agreements and licenses for our advanced technologies and national
security needs. The most basic consensus of the workshop is clear: now
is the time to consolidate and re-energize catalysis in the U.S., by

-   dissolving the traditional sub-disciplinary boundaries between bio-,
    molecular-, and surface catalysis to create an unified discipline
    with each of the former subgroups bolstering the others;

-   establishing catalysis as the central discipline and enabling
    technology for control of chemical transformation;

-   attracting via this Renaissance in catalysis some of the best young
    people who will revitalize the field.

The Department of Energy, the only Federal agency that supports
catalysis as a discipline, is uniquely positioned to lead the revolution
in catalysis research. *A new investment in catalysis, to be successful,
must involve the formation of multidisciplinary teams of experimental
and theoretical/computational scientists using national facilities with
equipment required to address challenges in catalysis that are too
complex and interdisciplinary to fit into existing funding mechanisms.
Support is needed for multi-institutional efforts that have enhanced
access to unique national facilities to make this promise a reality.*

## Introduction

***A. Background, Structure and Organization of the Workshop***

Recognition of the improved ability to measure and characterize
materials and processes at the nano-scale prompted the Basic Energy
Sciences Advisory Committee (BESAC) to commission a workshop to identify
challenges and opportunities for catalysis in the 21st Century. BESAC
was established on September 4, 1986, to provide independent advice to
the Department of Energy on the Basic Energy Sciences program regarding
the complex scientific and technical issues that arise in the planning,
management, and implementation of this program. BESAC\'s recommendations
include advising on establishing priorities for research and facilities;
determining proper program balance among disciplines; and identifying
opportunities for inter-laboratory collaboration, as well as program
integration, and industrial participation. The workshop was supported by
the Basic Energy Sciences program. The workshop agenda is reproduced in
Appendix A.

A broad selection of experts from national laboratories, industry and
universities was invited and about seventy-five of them contributed to
the workshop. Participants (Appendix B) were drawn from traditional
subdisciplines (homogeneous catalysis, heterogeneous catalysis,
biocatalysis), representing a variety of approaches to catalysis
(synthesis, dynamics, analytics and spectroscopy, modeling and
simulation, surface science and materials science). There were plenary
presentations and breakout sessions that addressed the status of
catalysis science and engineering and identified opportunities for
catalysis in this century, especially those emerging from improved
techniques for characterization, increased capabilities for theoretical
modeling using advanced computers, and recent breakthroughs in
nanoscience. Each breakout session produced a substantial summary
document, and this workshop report emerged from those contributions, the
discussions at the workshop and a one-day meeting of a small subset of
participants and other experts held in Los Angeles on December 19, 2002.

***B. Recent Advances in Experimental and Theoretical Methods***

The importance of catalysis to society was apparent at the outset of the
workshop. Catalysts--- chemical agents that bond selectively to reactant
molecules to expedite rapid, stepwise scission and formation of
individual chemical bonds and then uncouple (unchanged) from the
products to be used over and over again--- make possible efficient
control of chemical reactivity. A key advantage in catalysis is the
ability of catalysts to lower the activation energy of the process so
that we can control the chemical transformation steps leading to the
desired products with minimal input of energy. The petroleum, chemical,
and pharmaceutical industries, contributors of \$500 billion to the GNP
of the United States, rely on catalysts to produce everything from
transportation fuels to "wonder" drugs to paints to cosmetics. The
cleaner emissions of modern cars, the abundance of fresh food at our
stores, and our healthier lives from new pharmaceuticals are made
possible by the speed, efficiency and precision of catalysts. Nature's
catalysts, enzymes, show how amazingly efficient catalysts can be---
they make possible essentially all biological reactions---and, by
comparison with today's technology, they show how much opportunity there
is for improvement. Control and efficiency of chemical conversion
comparable to that demonstrated by Nature are in sight for countless
known and unknown reactions, as we learn how catalysts work and to
engineer them for specific reactions.

The opportunities to understand and predict how catalysts work at the
atomic scale have unfolded dramatically in the past twenty years with
the emergence of powerful predictive methods including density
functional theory; incisive instruments for imaging catalysts and
reactants at the nano and atomic scales, and dedicated facilities for
examining catalysts as they function, even at the high temperatures and
pressures used in industrial processes. Single-site catalysts are being
synthesized and their mechanisms elucidated. Developments in structural
biology leading to new insights into protein structure and activity are
providing inspiration for the design of catalytic structures. There is
an emerging ability to make uniform arrays of catalysts and to
manipulate and spectroscopically probe single molecules. Advances in
femto science will allow us to time-resolve structural changes on
ultrafast timescales, thus adding new dimensions to our understanding of
primary chemical reactions. Theory can now provide reliable calculations
of the thermodynamics and kinetics/dynamics for model catalytic
reactions. Combinatorial synthesis, rapid screening methodologies, and
cheminfomatics are providing leads to new catalysts at an unprecedented
rate. During the past few years scientists have developed an emerging
ability to use nano fabrication capabilities to make "man-made" or
artificially structured catalyst arrays on supports that are quite
different from those provided by Nature. New, powerful techniques such
as scanning tunneling microscopy, synchrotron and neutron sources,
computational methodologies implemented on multiple terascale computers,
and the impending construction of new nanoscience research centers all
converge on catalysis science to place it at the threshold of new
understanding and new technology. As these opportunities have expanded
explosively, so have the needs. For example, catalysts are needed (a)
for use in alternative energy sources and new conversion technologies
such as fuel cells and devices for photolytic splitting of water to form
hydrogen and oxygen, (b) for the manufacture of new materials such as
polymers with tailored nano-, micro- and macroscopic properties suited
for new technological applications, (c) for the precise synthesis of
molecules such as pure drugs without toxic stereoisomers, and (d) for
the production of chemicals with minimal energy input and without
environmentally damaging side products.

The convergence of new capabilities and deepening needs for advanced
catalysis research has coincided with a regrettable abandonment of
support for catalyst development by U.S. industry, as it has
discontinued most in-house basic catalysis research, along with a
debilitating erosion of governmental support. The U.S. has lost its
former position of world leadership in catalysis and now must scramble
to win it back. Other countries have recognized the tremendous
importance of catalysis science as a key to their economic
sustainability and environmental management practices. Accordingly, they
are devising strategies for developing catalyst R&D through joint
industry and university research programs, in many cases through the
creation and funding of multidisciplinary "catalysis institutes". *The
American way of conducting research has traditionally been more
conducive to innovation; we can and must regain our unquestioned
leadership role*. Delaying new investments in these critical sciences
will further erode the U.S. position. Further, it will increase our
dependence on imported technologies and our reliance on international
agreements and licenses for our advanced technologies and national
security needs. *The most basic consensus of the workshop is clear: now
is the time to consolidate and re-energize catalysis in the U.S.,* by

-   dissolving the traditional subdisciplinary boundaries between bio-,
    molecular-, and surface catalysis to create an unified discipline
    with each of the former subgroups bolstering the others;

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-   establishing catalysis as the central discipline and enabling
    technology for control of chemical change;

-   attracting via this Renaissance in catalysis some of the best young
    people who will revitalize the field.

#### The Grand Challenge

Many exciting specific challenges for catalysis were identified during
the workshop. Beyond this, a very compelling and fundamental challenge
became clear. Simply stated, *the Grand Challenge for Catalysis Science
in the 21^st^ Century is to understand how to design catalyst structure
to control catalytic activity and selectivity.* Meeting this challenge,
we will be able to activate selectively one bond in a multi-functional
reactant to produce a desired product. Developing a fundamental
understanding of catalyst structure and catalytic transformations at the
atomic and nano scales will enable a predictive capability in catalysis
science and allow the *design* of new catalysts and catalytic processes
that approach the ultimate goal: highly active and stable catalysts that
provide near 100% selectivity to a desired products with minimal use of
energy. The outcomes of achieving this challenge include (a) enhanced
energy efficiency with low cost fuels that produce fewer harmful
emissions, (b) the elimination of polluting by-products, (c) enhanced
homeland security and stockpile stewardship, (d) effective synthesis of
new and improved drugs, and (e) new materials with tailored properties.

We must develop a fundamental atomic and nao scale understanding of
catalysis. At this level of description, heterogeneous-, homogeneous-
and biocatalysis are the same, and it will be possible to develop a
common language. Increasing interactions between researchers having
different approaches to address the challenges of catalysis discussed
above will inevitably result in deeper insights and new technology to
benefit society in ways that today are alsmost unimaginable.

#### Enabling Approaches for Progress in Catalysis

Much of the current mode of research in catalysis follows the
traditional separation of the subdisciplines (homogeneous-,
heterogeneous-, biocatalysis) and approaches (experimental, theoretical
and computational, analytical and spectroscopic). Moreover, there is a
serious lack of communication between those involved in research in
catalysis, especially at universities, and those conducting research at
national facilities. Some participants believed that these various
communities have grown to be rather closed. Although this type of
separation into subdisciplines is not unique, it is clear that it is an
impediment for progress in catalysis. *A new investment in catalysis, to
be successful, must involve the formation of multidisciplinary alliances
and teams of experimentalists and theorist, including scientists using
national facilities, to address challenges in catalysis that are too
complex and interdisciplinary to fit into existing funding mechanisms.
Support is needed for multi-institutional, multidisciplinary efforts
that provide enhanced access to unique national facilities.* By working
side by side with those having other approaches, researchers will more
readily discover the commonalities of the underlying science and the
overarching problems. Younger investigators will benefit from
participation in such multi-investigator, multidisciplinary efforts:
they will be educated with a set of concepts and skills in *catalysis as
a central discipline* transcending the formal divisions of homogeneous-,
heterogeneous- and biocatalysis. A new generation of broadly educated
catalysis scientists with a new vision of catalysts will emerge.

This unified approach to research that combines exciting advances in
bio-, molecular-, surface- computational- and nano-science to address
common problems in catalysis science will be able to capitalize on the
following, for example:

-   The use of modern methods of genetics and biology to optimize enzyme
    structures for reactions under conditions different from those of
    Nature.

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-   The precise synthesis of catalysts as components of materials that
    facilitate efficient applications ranging from (a) active, selective
    molecular single-site catalysts, easily separable and noncorrosive
    because they are mounted on surfaces and in matrices, as in enzymes,
    to (b) such molecular catalysts sequenced in assembly lines as in
    mitochondria.

-   Design of the surfaces and matrices of these catalysts at the
    nano-scale to facilitate the transport of reactants, intermediates,
    and products for efficient applications.

Furthermore, catalysis scientists need to be educated about the
capabilities and the great potential value now existing or soon-to-be
available in the national facilities: high-brilliance photon and high
flux neutron sources, spatially resolved and atom specific microscopy
and spectroscopy, new terascale computational facilities, as examples.
Teams of researchers with expertise in and access to these unique tools
will realize their full potential to impact catalysis research.

#### Consensus Observations and Recommendations

A consensus emerged at the workshop on several key observations and
recommendations:

-   Catalysis will play an essential role in the solutions to major
    problems that face our society: energy, environment and more
    generally, the quality of life.

-   The time is right for catalysis science to make unprecedented
    strides forward toward new understanding and new technology, taking
    advantage of the recent exciting developments in rapid catalyst
    synthesis and screening techniques, theory and computation,
    breakthroughs in nanoscience, and the availability of powerful
    analytical tools, particularly those at our national facilities.

-   Ironically, these dramatic developments that position catalysis for
    a revolution have been occurring just when the level of industrial
    and federal support for basic research in catalysis has waned. The
    U.S. is no longer the preeminent world leader in catalysis. We can
    and must regain our former position of world superiority.

-   Catalysis scientists face a grand challenge, to understand and
    thereby control the relationship between catalyst structure and
    catalytic chemistry. We must develop a fundamental, atomic and nano
    scale understanding of catalysis to design new catalysts and new
    catalytic technology.

-   New investments in catalysis should encourage multidisciplinary
    alliances and teams, comprising experimentalists and theorists with
    increased access to our national facilities. Multi-investigator,
    multidisciplinary approaches will help establish catalysis as a
    central discipline, improve communication between scientists from
    differing traditional subdisciplines and educate a new generation of
    catalysis scientists.

-   It is time to reform some aspects of catalysis research beyond the
    single investigator mode. Although the single investigator,
    competitive research model has and will continue to be one of the
    foundations of American success, some particularly complex and
    challenging problems in catalysis require *integration* of the
    efforts of scientists with differing traditional approaches. This
    innovative combination of funding models will provide a coordinated
    national research agenda for catalysis science.

#### Opportunities for an Expanded Role for the Department of Energy

For the present and foreseeable future, the major source of energy for
the nation is found in chemical bonds. If scientists and engineers had
the ability to understand and thereby control the relationship between
catalyst structure and catalytic chemistry, the effects on energy
production and use in domestic as well as industrial applications would
be profound. The meeting of this grand challenge will allow the design
of completely new catalysts and catalytic processes for as yet
unimagined purposes and benefits.

The Department of Energy, through its Basic Energy Sciences Program is
currently providing the major funding for catalysis science and related
activities in the United States, about \$45 million annually (we need to
check this number and provide some consistency in how we word this visa
vis Ray's '04 Budget briefing). Many of the exciting recent developments
that have positioned catalysis for a revolution have already been
supported by the Program. The national facilities that will facilitate
the synthesis and characterization of new catalytic materials are
located at DOE laboratories. Whereas DOE has traditionally supported
multi-investigator projects at national laboratories, but not at
universities, it is clear that a reform in the way in which some aspects
of research in catalysis science is carried out would greatly benefit
its development. The Department is well structured to encourage and
evaluate the multi-investigator, multidisciplinary research programs.

#### Summary of Specific Challenges and Opportunities

There were a large number of challenges identified by the participants
at the workshop; however, the group was too small to represent
evenhandedly all areas of catalysis. The list below, although only a
partial catalog, nonetheless makes a compelling case for an increased
federal investment is catalysis. The challenges and opportunities
include the following:

-   To identify general trends and unifying principles that are common
    or specific to different classes of catalytic phenomena, (e.g.
    heterogeneous-, homogeneous- and biocatalysis.

-   To establish, using the latest in characterization diagnostics, firm
    relationships between catalyst structure, rates, and selectivity of
    elementary reaction steps.

-   To build close interactions between theoretical/computational and
    experimental researchers to develop advanced modeling and simulation
    tools that are accessible to the entire catalysis community.

-   To use catalysts to control the three-dimensional structures of
    products, including enantiomeric selectivity.

-   To prepare and screen families of prospective catalysts efficiently.

-   To create bases of theoretical and experimental data and the
    methodologies to perform data mining with the goal of optimizing the
    design of new catalytic systems.

-   To develop an understanding of the thermodynamics and kinetics of
    the nucleation, growth and sintering of supported metal catalysts.

-   To undertake *in situ* measurements of chemical, spatial, and
    temporal properties of working catalysts using state-of-the-art
    characterization methodologies, including existing and future
    synchrotron and neutron facilities.

-   To establish an understanding of the non-uniformity of catalytic
    reactions.

-   To predict by theory, using advanced computational resources, the
    essential surface species and kinetic parameters that govern
    catalytic steps in industrial heterogeneous catalytic processes and
    to provide the same type of thermodynamic and kinetic information
    for homogeneous catalysts.

-   To use catalysis to synthesize new nano-structures.

-   To prepare highly reactive, coordinatively unsaturated catalytic
    sites stably isolated on support surfaces, including single-crystal
    surfaces. Arrays of these sites will consist of multiple metal atoms
    and molecular catalysts sequenced in assembly lines as in
    mitochondria for tandem catalytic processes.

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-   To design and synthesize new, non-natural nanoporous and mesoporous
    supports for catalysts that control their chemical properties and
    isolate them in nanocages, controlling reactant access and product
    egress.

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-   To use the methods of nanoparticle synthesis to precisely construct
    clusters of metals, metal oxides, and metal sulfides on supports.

## Opportunities for Scientific Advances in Catalysis

##### *A. Catalysis and Nanoscience*

The electronic structure and chemical properties of compositionally
identical materials are transformed when their dimensions are reduced
from the macro- through the nano- to the Angstrom-scale. A
"nanoparticle" can exhibit distinct electronic and physical properties
compared to the corresponding bulk solid, and it should therefore
display unique catalytic properties. Indeed, it is well known that
nanometer-sized particles of a metal have catalytic properties that
differ markedly from those of larger, bulk-like particles of the same
metal. Examples include the selective oxidation of propylene to
propylene oxide and the oxidation of CO by nano-sized gold particles,
and the selective reduction of NO by nano-sized iron oxide particles.
Extraordinary advances in synthetic methods, in characterization
techniques, and in theoretical/computational approaches offer
unmistakable promise for new breakthroughs in the design of
nano-structured catalytic materials.

By using recently developed methodologies for nanoparticle synthesis, we
can control the size and composition of nano-scale catalysts, and with
better understanding of the connection between catalyst structure and
catalytic chemistry, it will be possible to tailor catalytic properties
to the precise needs of a particular process. By combining traditional
molecular strategies with recently developed nanoscience methodologies,
synthetic chemists working with materials scientists can now fabricate
new catalysts using numerous strategies such as templating, molecular
precursors, self-assembly, and lithography. These new advances in
synthetic methodologies provide unique opportunities to construct and
design nano-structured catalysts for optimum activity and superior
selectivity, keys to maximum catalytic efficiency. At the same time,
these advances in synthesis of nano-scale materials provide confidence
that the unique catalytic properties of any single nanoparticle can be
replicated into many kilograms of catalyst material, all of it
exhibiting the same catalytic properties whether for research,
pharmaceutical synthesis, or industrial processes.

Catalytic nanoparticles are typically anchored to a supporting solid
such as silica or alumina for stability toward sintering. Because these
materials are heterogeneous at the nano-scale, characterizing individual
catalytic particles has been a fundamental barrier to a molecular level
understanding. However, advances in nano-scale methods now allow, via
microscopic and single molecule spectroscopic techniques,
characterization of the structure and electronic properties of a single
catalytic nanoparticle and its unique catalytic chemistry. These new
characterization methodologies offer unprecedented opportunities to
detail the electronic and physical properties of nano-structured
catalysts and to "see" these catalysts function in a realistic
environment. By preparing nanometer-sized islands of one oxide (such as
TiO~2~ to which catalytic metal clusters are relatively strongly bound),
surrounded completely by domains of a second oxide (such as SiO~2~ to
which the clusters bind much more weakly), it should be possible to
greatly reduce catalyst aggregation into larger clusters, because there
is an activation barrier for diffusion of the metal from one TiO~2~
island to another across the SiO~2~ surroundings. This particular
example illustrates the more general point, that as we learn the atomic
details of how sintering and catalyst deactivation occur, we have the
opportunity to use nano-structure itself to inhibit these processes and
maintain nano-scale reactivity. The use of nano-structure in this way,
to maintain and control nano-structure, bears some resemblance to the
use of ligands to stabilize active catalyst centers in solution, and
begins to blur the traditional distinction between homogeneous and
heterogeneous catalysis by combining some of the best attributes of
both.

The use of catalysis to synthesize nano-structure presents still another
set of opportunities. The fundamental essence of catalysis is
controlling the rates at which chemical bonds are formed and broken, and
this is not limited to chemical bonds of small molecules. Materials
themselves are networks of chemical bonds, and, by controlling relative
rates of bond formation, catalysis can determine the composition,
properties, and morphology of materials, especially metastable materials
which cannot survive the rigorous conditions of uncatalyzed synthesis.
Some of the best examples are nanotubular forms of carbon. In figure A,
straight nanotubes of carbon are grown by catalytic conversion of
acetylene using iron/silica nanoparticles as catalysts. However,
sometimes nanotubes of carbon grow as **coils**, as when iron/indium
nanoparticles are used as catalysts for acetylene conversion, figure B.
The atomic details of what determines the pitch and handedness of these
coils -indeed, even the atomic details of why this coiling occurs or
does not occur- are not presently known. But as we learn these details
and better understand the relationships between catalyst structure and
catalytic chemistry, we will have the opportunity to prepare many other
forms of nano-structured matter that are presently unattainable.

![](media/image1.png) Figure A. Carbon nanotubes grown from acetylene
using Fe/silica nanoparticulate catalysts; Z. W. Pan et al, Chem. Phys.
Lett. 1999, 299, 97.

![](media/image2.png) Figure B. Carbon nanocoils grown from acetylene
using Fe/In nanoparticulate catalysts; M. Zhang et al, Jpn. J. Appl.
Phys. 2000, 39, L1242.

Clearly, complete mastery of the connections between catalysis and
nano-structure will be an extremely demanding challenge. Subtle changes
in the composition or electronic structure of a catalyst can trigger
large changes in its kinetic behavior, varied architecture of the
nano-scale environment will determine the stability and activity of
catalyst regions, and the nano-scale environment itself can be affected,
even created, by catalytic processes. Yet all these factors and their
effects, although complex, are not indeterminate. By using the tools of
nanotechnology and the guidance of theory and large-scale computations
(and biology), we can learn how to control particle size and
composition, to deliberately tune these effects to achieve desirable
catalytic chemistry, and to realize the dream of combining the best
attributes of heterogeneous catalysts (stability, longevity,
separability) and homogeneous catalysts (tunability, predictability,
controllability) in a new generation of catalytic materials*.*

##### *B. Molecular Catalysis on Surfaces: Merging Homogeneous and Heterogeneous Catalysis*

A revolution is underway in catalysis by molecular species on supports.
Molecular catalysts in solution offer the advantages of uniform
accessibility and uniqueness of structure that impart single catalytic
cycles and selective conversions. In contrast, solid catalysts offer
sites only at surfaces, which are non-uniform, with a spectrum of
reactivities and low selectivities. Uniform catalytic sites on surfaces
retain the advantages of those in solution, with the added benefits of
ease of separation from products, lack of corrosion, and robustness for
high-temperature operation. This field is in its infancy. There is a
compelling opportunity for precise design of surface catalytic sites for
specific chemical conversions, such as of abundant and traditionally
unresponsive feedstocks including methane and CO~2~. Ultimately,
supported molecular catalysts will rival enzymes in their
sophistication.

Most catalysts present coordinatively unsaturated metal centers that
allow activation by bonding of reactants as ligands. Syntheses of
supported molecular catalysts are carried out with precursor compounds
that can be anchored to the support with removal of the precursor
ligands. The optimum precursors include organometallic complexes with
reactive ligands that are easily replaced by the support. Research in
surface organometallic chemistry and catalyst synthesis has already led
to impressive commercial successes, illustrated by the "single-site"
metallocene catalysts for manufacture of polyolefins with tailored
structures (production rates already exceed 100 billion pounds per year)
and the Acetica™ catalyst (a rhodium complex anchored to a
functionalized resin) for methanol conversion to acetic acid. Whole new
families of molecular surface catalysts may be envisioned, emerging from
synthesis that involves integration of design of catalytic sites with
nano-scale design of porous supports:

-   **Highly reactive, coordinatively unsaturated cations stably
    isolated on support surfaces.** This family of catalysts provides
    high activity and selectivity with the catalytic sites stably
    isolated, accessible to reactants and protected from reactions with
    each other that would cause deactivation.

-   **Arrays of these sites consisting of multiple metal atoms and other
    structures.** This family represents new kinds of bi- or
    poly-functional catalysts that can be used for sequences of
    reactions and facilitation of thermodynamically unfavorable steps in
    catalytic cycles. Moreover, this strategy allows molecular catalysts
    to be sequenced in assembly lines as in mitochondria for tandem
    catalytic processes.

-   **Arrays of these sites mounted on regular (crystalline) surfaces.**
    The support will contribute to the preciseness of structure of
    catalysts as a whole for this family. Supported catalysts with
    chiral ligands (including the support) can be prepared for selective
    synthesis of biologically active molecules such as drugs. Progress
    will spring from continuing integration of nanomaterials science
    with catalysis.

-   **Design of nanoporous and mesoporous supports.** Development of
    this family of catalysts is a vigorous and expanding field; the
    supports will be selected both for their chemical properties (as
    ligands for the metals) and physical properties (controlling the
    steric environment of the sites as well as reactant access and
    product egress). Supports will range from hard (inorganic)
    structures to soft structures, including organic polymers, micelles,
    and inorganic surfaces functionalized with fuzzy organic layers to
    control the reaction environment. Catalytic sites can be stabilized
    by isolation in nanocages (e.g., in zeolites) and in nano-structured
    nests anchored to supports*.*

-   **Precisely constructed clusters of metals, metal oxides, and metal
    sulfides on supports.** Nanoclusters of metals, oxides, and other
    materials have new, undiscovered properties different from those of
    the bulk; they are a new kind of single-site catalyst. Preparation
    of these nanoclusters on supports, especially when they are uniform
    and/or present in structured arrays, will lead to new catalytic
    properties, including coordinative unsaturation, defects, novel
    redox properties, and controlled acidity and basicity, and these can
    be varied over wide ranges. These properties can be controlled by
    selection of the sizes and compositions of the nanoclusters and
    their interactions with supports. Even extremely subtle changes in
    the electronic structure of a catalyst can trigger large changes in
    its performance, and a major challenge is to tune the catalytic
    properties by variation of the catalyst structure on the atomic and
    nano scales. Catalysts with narrow size distributions are needed,
    both to facilitate rapid fundamental understanding and to provide
    high selectivities and production with minimized undesirable
    products. Methods for preparing these catalysts, such as patterning,
    imprinting, and selective surface organometallic synthesis are
    developing rapidly, guided by theory and computation.

These new materials---tailored molecular catalysts on tailored
supports---offer the

prospects of entirely new catalytic properties combined with the
following advantages:

-   They can be characterized incisively, even in the working state, by
    methods available at modern facilities offering high-flux sources of
    photons and neutrons and by spatially resolved atom-specific
    microscopy and spectroscopy.

-   They can be modeled accurately with modern theoretical/computational
    methods.

Thus, the development of this class of catalyst will mark a new era of
rapid advancement in catalytic science and technology as powerful
theoretical and experimental methods are brought to bear
synergistically. These are the catalysts that will bring researchers to
a common focus and dissolve the boundaries between the traditional
subdisciplines of homogeneous, heterogeneous, and biological catalysis,
thrusting catalyst design from a tantalizing hope to commercial reality.

##### *Biocatalysis*

The biological cell provides a paradigm of an integrated catalytic
system from which we can learn valuable lessons. Complex networks of
reactions are precisely controlled and regulated with reactions
occurring in aqueous solution and at organic-aqueous interfaces. The key
components of this system are enzymes, Nature's catalysts, that can
accelerate chemical reactions enormously (up to 10^17^-fold) and exhibit
extremely precise chemo-, regio-, and stereocontrol. The fields of
biochemistry, molecular biology, and cell biology have all contributed
greatly to our understanding of how enzymes perform their cellular
functions. As a result, enzymes have not only provided the inspiration
for the development of many ingenious chemical catalysts but they are
now, themselves, being used to great effect in industrial applications.
However, there remains a large knowledge gap in understanding the nature
of biological catalysis that must be filled before the full potential of
enzymes as industrial catalysts can be harnessed.

Over the last twenty years or so there has been an increasing interest
in exploiting enzymes as industrial catalysts for both natural and
non-natural chemical processes. Indeed, today there are numerous
commercial examples of biological catalysis including fermentations,
whole cell biotransformations, and the use of isolated enzymes (see side
bar for a few examples). Although these successes are significant, the
challenge remains to more fully integrate biological catalysis with
chemical catalysis and chemical synthesis, maximizing the potential of
each. The field is poised for tremendous breakthroughs in the next
decade that can have a huge impact on a number of important markets
including pharmaceuticals, fine chemicals, fuels, and commodities.

***New Enzymes for Biocatalysi*s**

There is an urgent need to expand the toolbox of currently available
biocatalysts to access new chemical conversions. Many researchers in
academia, government and industry have developed technologies for the
discovery of novel biocatalysts, including screening of culture
collections and, more recently, screening of libraries constructed by
the direct isolation of DNA from uncultured environmental samples. These
programs continue to place an emphasis on targeting new classes of
biocatalysts with commercially useful properties, such as new
selectivities, higher catalyst stability, and expanded pH and
temperature tolerance. Currently the class of enzymes most widely
applied to organic synthesis is the hydrolases. However, there are
opportunities for the application of enzymes from all six classes
(oxidoreductases, transferases, hydrolases, lyases, isomerases, and
ligases), and increased biocatalysis research is needed in each class.
Oxidoreductases, in particular, catalyze some of the most useful
chemical transformations that are often beyond the reach of synthetic
organic chemistry, such as the regiospecific hydroxylation of alkanes,
yet they remain underutilized in industry. This is in part due to the
need for new enzymes and in part due to the need for expensive cofactors
such as NADH/NAD^+^, NADPH/NADP^+^, FADH/FAD^+^, PQQ, and ATP/ADP. A few
cofactor regeneration systems have been developed but there is a need
for additional research and innovative solutions are sure to arise from
collaborations between biochemists, catalysis chemists and
electrochemists.

***Biocatalyst Optimization by Evolution***

In a few cases, rational redesign of existing enzymes by site-directed
mutagenesis has led to improvements in activities. However, such efforts
have more commonly met with little success. The lack of success can be
attributed to a lack of understanding of enzyme mechanisms and
structure-function relationships. Rational mutagenic techniques are akin
to the laborious stepwise chemical methods for improvement of
non-biological catalysts. As is the case with non-biological catalysts,
successful application of these techniques can come only from more
fundamental research to shed further light on how enzymes function at
the atomic scale. Exciting developments can be envisioned to emerge from
application of new structural and spectroscopic techniques such as
atomic force microscopy, time resolved X-ray crystallography, and
neutron scattering techniques.

In contrast to the rational design approach, several more stochastic
methods for enzyme improvement have been developed in the last decade.
These methods draw upon the power of natural Darwinian evolution.
Details of the techniques vary, but the directed evolution approaches
all involve an iterative process of random mutation and high throughput
screening to uncover new enzyme variants with improved properties. In
this way no prior knowledge is required as to how the three-dimensional
structure of the enzyme affects its properties. Directed evolution
programs can test hundreds of thousands of variants and thus sample
large areas of sequence space. Results from such analyses can give
valuable information about biological solutions to a given phenotypic
challenge and can be used to further understand enzyme
structure-function relationships. Ultimately the goal will be to predict
enzyme structure and function from the primary amino acid sequence. In
the meantime, these evolution-based technologies provide rapid access to
biocatalysts, tailored to meet the demands of a particular chemical
process, including those occurring under extreme conditions not
typically found in the cellular environment (e.g. environments of high
acidity, high temperatures, and non-aqueous solvents).

***Integrating Biological and Chemical Catalysis***

The pharmaceutical industry continues to demand single-enantiomer drugs,
and thus the importance of enantioselective catalysts including
biocatalysts can be expected to increase. Biocatalytic conversion of
renewable feedstocks derived from cellulose, hemicellulose, starch, and
plant oils into desirable products, including transportation fuels such
as ethanol, hydrogen, and biodiesel, is an important economic target.
This significant challenge will need long-term, interdisciplinary basic
research to establish appropriate scientific foundations. In all cases,
the full economic and productivity potentials of a process built around
biocatalysts can be achieved only by successfully integrating the
biocatalysis step in the context of upstream and downstream chemical
processing, chemical synthesis and catalysis.

As heterogeneous-, homogeneous-, and biocatalysis merge into an
integrated catalysis science, new developments that take advantage of
the synergies can be anticipated. Combining biocatalysts and chemical
catalysts can lead to exciting possibilities. One recent example is the
development of dynamic kinetic resolution processes such as the
stereoselective esterification of racemic alcohols using an
enantioselective lipase in tandem with a ruthenium-based racemization
catalyst. Future work bringing together two or more different catalysts
with complementary activities could lead to the ability to perform
entirely novel chemical transformations. In a homogeneous system, an
enzyme and a non-biological catalyst would need to be compatible;
directed evolution may be used to optimize the enzyme's compatibility.
Alternatively, the catalysts could also be spatially separated. For
example, it may be possible to create ordered arrays of catalyst centers
immobilized along nano-structures in such a way that a substrate can be
processed along the complex of catalysts to give a unique product,
perhaps even going through metastable intermediates. In some aspects
this type of substrate channeling along such a complex would be
analogous to what takes place in natural modular enzyme systems such as
polyketide synthases or non-ribosomal peptide synthetases. To attain
these types of integrated catalytic systems considerable challenges must
be overcome. Research should be focused on developing new and mutually
compatible biocatalysts and chemocatalysts under an integrated research
program.

***D. Tools Required to Advance Catalysis Science in the 21^st^
Century***

***Synthesis and Characterization***

Chemical synthesis, the production of more complex and more valuable
molecules from simpler reactants, is the *raison d'être* of catalysis.
New approaches to characterization of catalysts will improve the
identification of possible species that make this synthesis occur. The
focus of synthesis in catalysis includes the formation of a target
molecule from a catalytic reaction, as well as the formation of the
target structure of a catalyst used for these reactions. Underlying the
Grand Challenge of connecting catalyst structure with catalytic
chemistry are more specific challenges in synthesis. To meet our Grand
Challenge, we must understand the connections between catalyst structure
and both catalytic activity and selectivity.

Progress in catalytic synthesis will change the quality, economics, and
energy consumption of our lives. Each investigator has a personal list
of the most important chemical transformations that catalysis could
tackle in the future. For example, most lists include the catalytic
production of new fuels and chemicals by selective oxidation of alkanes
such as methane. Current commercial "gas-to-liquid" processes involve
costly, endothermic steam reforming of methane to synthesis gas (CO +
H~2~), followed by conversion to methanol by CO hydrogenation or to
higher hydrocarbons by Fischer-Tropsch synthesis. Direct selective
oxidation to liquid fuels (methanol, gasoline, or other liquid fuels)
would allow for low capital-investment plants directly at gas wells,
more energy efficient production and lower CO~2~ emissions. Tremendous
economic and environmental benefits would also be realized by the direct
utilization of alkanes as feedstocks for the synthesis of value-added
chemicals to reduce energy costs and waste streams in the front end of
chemical production. The development of new electrocatalysts also lies
on most top-ten lists for catalysis. Fuel cells represent one of the
greatest opportunities for clean and efficient power generation,
including energy for transportation, but more efficient cathodes as well
as efficient anodes that utilize fuels other than hydrogen are needed to
allow *direct* oxidation of liquid fuels such as methanol. The
utilization of renewable carbon sources must be a priority for the first
half of this century. Petroleum resources are limited but currently are
being relied upon to provide virtually all of the feedstock for the
global chemical industry. This short selection of potential new
technologies demonstrates that improved catalysts can impact the source
of our energy, the identities of our fuels, and the efficiency at which
this energy is used.

Using the power of chemical synthesis and new, more powerful methods of
characterization, we must strive to understand the connection between
catalyst structure and rates, order, and selectivity of the elementary
reactions in a catalytic cycle*.* More specifically, we must understand
how catalyst structure controls the relative rates and order of the
individual, single-step reactions, typically called elementary
reactions, of a catalytic cycle. If we can understand the connection
between structure and rates of elementary reactions, we will be able to
alter catalyst structures in a rational way to increase or decrease the
rates of individual desired and undesired elementary reactions. This
control over rate will allow us to design catalysts that are active
enough to cleave strong bonds and selective enough to react at one
position of a multifunctional molecules; active enough to form the
desired product at high rates, and selective enough to form all
undesired products only at low rates. Such challenges can be met: for
example, enzymes cleave the C-H bond of methane in the presence of many
typically more reactive bonds.

New synthetic methods employing catalysts must be developed to control
the three-dimensional structures of products. The benefits of
selectivity in catalysts extend far beyond a selection of one type of
bond over another. Most molecules have a three-dimensional structure
that controls their properties and ultimate utility. Millions of tons of
linear butanol are bought each year, but branched butanol is nearly
useless; billions of dollars of single-handed or single-enantiomer drugs
are bought each year, and the other handed isomer, or enantiomer, is
useless and even harmful (e.g. the presence of the undesired
stereoisomer in thalidomide was the cause of birth defects). The
selectivity of a catalyst can dictate the three-dimensional structure of
reaction products, but our understanding of the connection between
structure/reactivity and this type of selectivity is rudimentary, and
our understanding of this connection to design catalysts that control
product architecture must be improved. Catalysts can be used to control
the relative connectivity of atoms (regiochemistry), orientation of
groups at a flat carbon-carbon double bond (*E*/*Z* selectivity),
geometry at one carbon atom relative to another (diasteroselectivity),
and handedness (enantioselectivity) of the entire molecule. Again, we
know this challenge can be met: Nature's enzymes produce single
enantiomers of amino acids and single diastereomers and enantiomers of
more complex molecules such as steroids. We must become adept at
generating practical catalysts for the construction of chemical building
blocks like amino acids and complex molecules such as natural products.

We should undertake the efficient preparation of families of prospective
catalysts*.* We will never reliably create a new chemical reaction or a
faster version of an existing reaction by preparing just one prospective
catalyst until we understand all of the details of how to design a
catalyst from first principles. The road to increased activity and
selectivity is paved by a myriad of structures that will teach us by
experience their connections to activity and selectivity. Thus, we need
to create new types of catalyst structures and new methods for catalyst
preparation to provide the data and experience to show what makes a
catalyst active and selective. To date, this synthesis of catalysts has
often consumed more time and more effort than the testing of these
catalysts. Thus, we must open the bottleneck of catalyst synthesis by
learning better methods to prepare families of catalysts. A paradigm
shift has begun to occur in the way catalysts are prepared. The
combinatorial synthetic process that is the new *modus operandi* of the
pharmaceutical industry has been tested recently as a method to prepare
catalysts. Heterogeneous, biological and synthetic homogeneous catalysts
have all been prepared as groups of structures, commonly called
libraries. The number of such libraries is small, and the number of
members of most such libraries is also small. However, these studies
have shown the potential to mine for catalyst structures in a new way.
For example, BINAP complexes are among the most famous and common
catalysts for many enantioselective reactions. To date roughly 1,000
derivatives of this ligand have been prepared, but it took 30 years to
prepare them. We must find structural types that generate equally active
and selective catalysts that allow us to prepare a thousand derivatives
in 30 days, not 30 years. Both biology and chemistry have shown the
potential to prepare molecules in large numbers. Thousands of mutants
are now commonly produced in a single experiment, and four years ago, a
library of a two million molecules was prepared to connect molecular
structure with biological activity. A key need in the area of
combinatorial synthesis for catalysis discovery is the development of
tools for measuring and screening catalyst properties of many potential
catalysts at once.

One great strength of homogeneous, molecule-based catalysts is the
exquisite control now possible over the stereoelectronic environment in
which substrate molecules are activated and undergo various
transformations at a reactive center, and at which products are
subsequently desorbed. In several areas (e.g. asymmetric catalysis and
single-site olefin polymerization) the sophistication of ligand
"engineering" for desired selectivity has reached impressive levels,
with selectivities sometimes exceeding those of enzymatic systems. Great
opportunities now exist for extending these capabilities by combining
elegant molecular synthesis with other methods, including nano-scale
structuring, to modify the local environments in which catalysis takes
place. The consequences will be new generations of more efficient,
selective, and versatile "hybrid catalysts" that combine the best of
molecularly engineered homogeneous catalysts with the unique
environments that only nano-scale solvent, organic structural, and solid
state environments can provide.

The various environments can be divided into covalently connected,
solution phase, soft (organic) structures and hard (inorganic)
structures. In the former, multinuclear catalytic centers involving
cooperative interactions between suitably ligated metal ions or between
ligated metal ions and other proximate functional groups effect or
enhance transformations not possible with a single metal center. Recent
promising results involve dimers and polymers, clusters, and dendrimers.
Unique solution-phase modifications in actual catalyst environment
include unusual/useful solvents such as ionic liquids, supercritical
solvents, or multiphase systems (e.g. fluorous biphasic catalytic
systems). Here the attraction is in providing unusual polarities (e.g.,
for accelerating certain substitution reactions), and solubilities
(i.e., increasing concentrations of relatively insoluble gaseous
reagents), or providing means of separating the reactant, product, and
catalyst. Soft environments for modifying catalytic pathways can include
micellar nanoreactors, self-assembled coordination compounds,
surfactants, and the internal environments of proteins. The attraction
here is to modify the local substrate concentrations and/or the
characteristics (e.g., size, shape, and polarity) of substrates that can
access the active site and/or the orientation(s) in which the substrates
can approach the active site and to modify the electrostatic environment
at the active site. Moreover, it is possible to create "hard" inorganic
environments for molecular catalysts. The strategy here is to select,
via nano-scale structural engineering, substrates that can approach the
catalytic center (on the basis of shape, size, and polarity); to allow
only certain portions of the substrate to attain close proximity to the
metal center; to protect certain parts of the catalyst ligation from
aggressive reagents and/or to prevent catalytic species from undergoing
deactivating dimerization reactions; or to produce products with unique
anisotropy, such as oriented polyolefin chains produced in mesoporous
matrices.

Hybrid and supported catalysts present particularly demanding challenges
for their synthesis and characterization; a close coupling of these is
essential. There are two strategies for performing truly molecular-level
studies of catalytic chemistry on nanoparticle catalysts: combining
single-particle characterization with single-molecule spectroscopy or
macroscopic materials and chemical characterization applied to
atomically-uniform arrays of nanoparticle catalysts. A number of
synthesis and characterization methods are available that can be used
with each strategy.

The single-particle approach can be implemented using nanoparticles
anchored on a planar, model catalyst support. Synthetic methods include
the following: evaporation of metals, employing nucleation and growth
phenomena to manipulate particle sizes; deposition of soft-landed
mass-selected nanoclusters from the gas phase; self-assembly on
templates or strain-relieved supports; electron beam lithography;
synthesis based on molecular precursors of nanoparticles; exchange or
anchoring of molecular precursors in solution and deposition of oxidic
precursors by wet chemical impregnation; spontaneous deposition on
electrode surfaces; and nanomachining of metal clusters.

The approach using uniform particle arrays starts with uniformly
structured support materials that achieve site isolation combined with
molecular building block technologies. Many methodologies have been
developed for fabrication of inorganic porous support materials. They
include sol-gel synthesis, colloidal growth, template directed
self-assembly, and supramolecular chemistry. In some cases, particularly
with template directed self-assembly, it is possible to produce highly
uniform porous structures. Impregnation of these structures with
molecular precursors of nanoparticles (e.g. multi-nuclear organometallic
complexes or metal-containing dendrimers) can lead to nanoparticles with
exceptional uniformity.

*Prospects for Success:* Not just Evolution, but the results of a large
amount of experimental work with our own hands, have shown that we are
at the cusp of meeting the synthetic challenges described above. For
example, we have begun to understand the mechanism by which a variety of
enzymes cleave alkane C-H bonds, and we have developed synthetic,
abiological catalysts that functionalize alkanes at a single position
with selectivities higher than any enzyme. A synthetic metal complex has
even been shown to react with methane in preference to its typically
more reactive oxidation product methanol. Yet, the highly regioselective
functionalization of alkanes is not yet practical for large-scale
synthesis, and the selective reaction with methane is not yet catalytic.
Several catalytic reactions with control of regiochemistry have also
been discovered recently. Addition of olefins to arenes with
anti-Markovnikov (linear) selectivity instead of the Markovnikov
(branched) selectivity of simple acid-catalyzed reactions has been
reported, and additions of amine N-H bonds to vinylarenes with control
over formation of either linear or branched product has been
accomplished. Yet, more work is needed to make these systems reactive
enough to be practical. Even one of the pillars of homogeneous
catalysis, regioselective propene hydroformylation, is poorly
understood. This reaction of hydrogen, carbon monoxide, and propene
occurs with regioselectivity high enough to comprise one of the
largest-scale chemical reactions. However, the regioselectivity is low
enough that subsequent, energy-intensive, separations are still needed.
Highly regioselective reactions with other alkenes, as simple as the
four-carbon-containing butadiene, remain to be developed. A Nobel prize
was recently awarded for the spectacular development of enantioselective
catalysis that produce one hand of a product with high selectivity.
However, the number of enantioselective reactions that are efficient
enough to be used commercially can be counted on the fingers of one
hand. Low turnover numbers, limited substrate scope, and the use of
specialized reagents are commonplace for enantioselective reactions. We
must overcome these limitations to realize the full potential of
catalyst selectivity. The success of several enantioselective reactions
in commercial synthesis does show that additional reactions influenced
by highly active and remarkably selective catalysts will emerge if
support to meet these synthetic challenges is provided.

*New Characterization Requirements:* Catalysis represents the ultimate
challenge for characterization, with reactions occurring at specific
atomic sites in a complex system, on a short time scale, and at high
temperatures and pressures. The ideal characterization tool should
provide atomic-level spatial resolution, temporal resolution and
chemical specificity under realistic reaction conditions. Although
enormous advances have occurred in surface microscopies, transmission
microscopies, the use of neutron and photon beams, and in the
application of theoretical methods, many challenges remain.

Current studies of catalysts employ a wide variety of techniques, such
as XPS, EXAFS, XANES, UV-Vis, vibrational spectroscopies, solution and
solid state NMR, etc., to describe the local and electronic catalyst
structure. Surface science methodologies are superb at detailed
characterization of uniform, macroscopic samples; however, for
nano-scale, disordered, or amorphous catalysts or supported molecular
catalysts with structures between these two boundaries, traditional
techniques fail to generate sufficient structural detail for a true
molecular-level understanding. As the catalyst design methodologies blur
the boundaries between homogeneous-, heterogeneous-, and biocatalysis,
new characterization tools and techniques must be developed that are
capable of addressing the multiple length scales present in complex
catalyst systems as well as the multiple time scales to resolve the
individual processes comprising the overall catalytic reaction.

A future challenge in the characterization of complex nano-structured
catalysts will be the adaptation of techniques currently employed in
biological and materials science. For example, NMR techniques for
determining solution protein structure or solid state dipolar decoupling
techniques for the determination of local structure in solid state
systems could be applied to enzyme-substrate interactions in solution or
to the local structure of adsorbates bound to solid phase
nano-structured catalyst systems. Breakthroughs are envisioned when the
combination of these advanced techniques leads to coherent descriptions
of the structure and activity of catalyst systems on length scales from
1 to 100 nm. These breakthroughs will likely include developing *in
situ* sample cells or reaction vessels where multiple techniques can be
used at neutron and/or X-ray scattering facilities. The combination of
neutron-based structural and vibrational methods with synchrotron-based
spectroscopies and *in situ* product analysis will unquestionably
produce new insights into catalyst structure and function. This
particular combination is exceptionally powerful because of the
variation of sensitivity among light and heavy elements for X-ray and
neutron-based methods. Many of these techniques will take advantage of
isotopic enrichment or substitution of the catalyst or the substrate(s)
to reveal information on local structure and reaction pathways.

High-resolution microscopy (both scanning probe and electron microscopy)
can image individual nanoparticles at the atomic scale. *In-situ*
high-pressure transmission electron microscopy (TEM) can achieve atomic
resolution under gas pressures up to a few Torr; the first exciting
results, showing morphology changes of Cu/ZnO under methanol synthesis
conditions, were reported recently. For elemental mapping of
compositions and determination of oxidation states, electron energy loss
spectroscopy (EELS) can be used within the high resolution TEM. Atomic
force microscopy (AFM) is an attractive probe for nano-structures
supported on thick insulating oxides. Scanning tunneling microscopy
(STM), can operate over wide temperature and pressure ranges.
Synchrotron-based X-ray techniques (EXAFS, XANES, standing waves) are
ideal tools for *in-situ* studies of local atomic structure,
nearest-neighbor distances, and coordination of small clusters. Time
resolved *in-situ* X-ray diffraction (XRD) of nano-structures and the
monitoring of sample stability and phase transformations in reactive
environments is evolving. Infrared, Raman, and sum frequency generation
spectroscopies, now being used for studies of catalysts at elevated
pressures, will provide insight into molecular characterization of
nano-structure reactivity. Techniques that can be used to examine
reactivity on a particle-by-particle and even on a site-by-site basis,
especially under typical reaction conditions (high pressure and
temperature), such as near-field optical spectroscopy and
single-molecule Raman are potentially powerful probes of single particle
chemistry. Femtosecond time resolution based on pulsed free electron
sources can potentially provide, in pump-probe experiments, the time
evolution of the valence electron density and illustrate just "how
electrons do it." Spin polarized neutron experiments can be used to map
out the electron distribution of paired spins in catalytic systems,
providing a unique link to theory.

New computational techniques must be developed to jointly analyze the
data from such studies and provide a self-consistent representation of
the structural and electronic features of the operating catalyst under
realistic conditions. Combined characterization and modeling methods
could also generate information about catalyst synthesis events, such as
the nucleation and growth of nano-scaled, nanoporous, or self-assembled
materials used as catalysts or supports. Integration of these techniques
to fuse data with molecular modeling and simulation tools will
facilitate analysis of data with unprecedented detail.

***Theory, Modeling and Simulation***

The development of new theoretical methods, algorithms, and software
which incorporates these advances on advanced high-performance, parallel
computer architectures (soon with up to 100's of TFlops of sustained
performance) promises to enable new understanding of the fundamental
behavior of chemicals and materials at the atomic and nano-scales. These
new hardware and software developments are revolutionizing the sizes and
types of chemical systems that can be treated and will enable scientists
to use computational chemistry and physics for the design of new and
improved catalysts. The role of theory and computation has been changing
dramatically as computers, software, and algorithms improve. Modeling,
theory, and simulation can enhance our understanding of known systems.
They can provide both qualitative and quantitative insights into
experimental measurements and guide the choice of which experimental
system is most worthy of study or enable the design of new systems. This
approach is most useful if the simulation has been benchmarked on
well-established systems to validate it. Furthermore, simulation allows
one to explore temporal and/or spatial domains that are not accessible
by present experimental methods. For example, it is possible to explore
different chemical reaction pathways not directly accessible by
experiment to learn why they are not favorable or to find missing steps
in a complex multi-step mechanism. In addition, accurate simulations can
actually replace experimental measurements that are too costly, too
difficult, or too dangerous to perform. Computational chemistry is an
enabling tool for addressing challenges in the optimal design of
processes for controlling and enabling chemical transformations leading
to processes that have high selectivity, and minimal environmental
impact and energy consumption.

Whereas Nature is very effective at designing catalysts such as enzymes,
we are decidedly less so. The most common approach to catalyst design
has often been Edisonian: Try something; if it works, try to improve
upon it by systematically changing the chemical nature of the catalyst.
If it doesn't work, try something else. This approach is highly
intensive, both in terms of time and expense, and it usually does not
work well. Furthermore, catalysts developed by this approach often
produce undesirable by-products, and the catalyst itself may pose an
environmental hazard. For many catalytic processes it is still unclear
just how the catalyst works at the molecular level. A much more
desirable approach to catalyst design is to analyze at the molecular
level exactly how catalysts function and to use this information to lead
to the discovery of new catalysts and to optimize the design of others.
Without this information, it is impossible to "tune" the catalyst to
have the desired effect. For example, even the most sophisticated
experimental techniques are unable to provide many of the details of
chemical reactions occurring at the surface of a catalyst or information
about how to tune a molecular catalyst to gain a factor of 2 to 4 in
performance. To truly advance the area of catalyst design, we will have
to take advantage of advanced high performance computer hardware coupled
with advanced theories and software/algorithms.

The computational design of practical catalysts for industrial and
commercial applications will require the ability to predict, at the
molecular level, the detailed behavior of large, complex molecules as
well as solid state materials. Although intermediate-level computations
can often provide insight into how a catalyst works, the true
computational design of practical catalysts for industrial and
commercial applications will require the ability to predict accurate
thermodynamic and kinetic results, as a factor of 2 to 4 in catalyst
efficiency can determine the economic feasibility of a process. An error
of only 1.4 kcal/mol in reaction energies leads to an error in
predicting an equilibrium constant of a factor of 10 and the same error
in the activation energy leads to an error of a factor of 10 in a rate
constant at 298 K. The requirement for such accuracy means that we must
be able to predict thermodynamic and kinetic quantities to very high
accuracy, on the order of tenths of a kcal/mol for thermodynamic
properties and reaction rates to 25% -- a daunting computational task.

There are enormous technical challenges in the computational design of
catalysts. These include the number of different spatial and temporal
scales that must be considered, the size of the active domain, the need
to treat heterogeneous structures, the need to consider the effective
environment in which the catalyst acts (gas-phase, solid-phase,
solution-phase, and interfaces), and the need to treat complex metal
interactions as most catalysts involve transition or lanthanide metals.
Moreover, one has to be able to properly include the effects of
relativity for systems with heavy metals. Finally, it is key to be able
to predict reaction rates as catalysis is inherently about the control
of chemical transformations at the molecular level.

Another set of challenges is that catalysts need to be designed for use
in real environments such as chemical reactors. This means understanding
reactor technology as well as materials properties at an unprecedented
level. For example, the hydrocarbon oxidation catalyst, vanadium
pyrophosphate, needed to be coated to make it tough enough to survive in
a fluidized bed reactor. The design of the coating to protect the
catalyst is just as important as the design of the catalytic material.

The key advances that have occurred in making reliable predictions of
catalyst behavior are developments in electronic structure theory. The
two methods that have had and will have the most impact are high level
ab-initio molecular orbital theory such as coupled cluster methods
(CCSD(T)) and density functional theory (DFT), including Car-Parinello
dynamics simulations. The former can be used to provide benchnmark
calculations of the thermodynamics and kinetics of small to medium size
model systems against which the more approximate DFT methods can be
tested and validated. Electronic structure methods, in particular DFT,
are now able to treat molecular systems of sufficient size and
complexity to be relevant to catalysis. The accuracy has reached a level
at which trends in interaction energies and activation energies can be
described allowing for predictions of trends in reactivity. This points
directly to electronic structure theory as an important factor in the
design of new catalysts -- the ability to aid in the development of
qualitative trends based on correlations of experimental and
computational results. Even more importantly, the computational methods
are becoming reliable enough to allow for the development of
*quantitative* concepts -- that is, concepts that can be used to direct
our thinking about new processes and catalysts. For example, the
development of a new alloy catalyst for ammonia synthesis was driven by
modern computational methods (Figure ).

A second example of the use of computational approaches to catalysis was
the development of a fluoride affinity scale that allowed scientists at
DuPont to order the Lewis acidity of very strong Lewis acids. This led
directly to the design of a mixed metal catalyst for the liquid phase
production of the refrigerant HFC-134a, the only such available
liquid-phase process. The process was not commercialized due to
solubility problems of the catalyst, highlighting the need to understand
the fundamentals of the entire process.

The goal of fundamental computational and experimental catalyst studies
is to develop an understanding at the molecular level of how chemical
bonds are transformed and how one can control these transformations.
This means understanding the detailed steps in chemical reaction
mechanisms and having knowledge of the thermodynamics and kinetics of
the various steps. New computational and experimental approaches are
enabling scientists to gain detailed insights into the steps involved in
chemical bond formation and how one can control the energetics of
transforming the chemical bonds from a set of reactants to a set of
products. For example, what needs to be known to control the oxidation
of small organic molecules? One needs to understand the potential energy
surfaces governing the oxidation of the organic molecules leading to the
most stable product CO~2~, which is usually undesirable (unless one is
trying to destroy a compound such as a pollutant) to control the
reactions so that this path is not followed. Besides the obvious impact
on the chemical industry, the controlled oxidation of alkanes is a
critical component to the use of renewable resources for fuels and
feedstocks as well as to the production of liquid fuels.

The above discussion points out the need for the development of a
systematic informatics for catalysis. Systematic thermochemical and
kinetics data for well-characterized systems are essentially absent,
making it difficult to develop reliable structure-reactivity
correlations. Computational approaches will be the most efficient way of
generating systematic databases, especially as there has been a loss of
U.S. expertise and capability in the measurement area for these
important properties. Computation will play a larger role as the methods
provide more accurate and reliable results and as computers get faster
enabling the study of more and larger systems. One example of such an
approach is the prediction of Lewis acidities for which reliable
experiments are not available. In another example, the heat of formation
of the key reactive intermediate OH has been revised by 0.5 kcal/mol
from a 50-year-old value with an uncertainty of [+]{.underline}0.05
kcal/mol, on the basis of a combination of very high level computation
and experiment. Quantities such as the free energy of solvation of ions,
even those as simple as the proton, cannot be easily obtained from
experiment, but new theoretical approaches now allow one to calculate
such quantities with some reliability.

Powerful theoretical tools are emerging as key ingredients of modern
catalysis research. Semi-empirical and first-principles quantum
mechanical (QM) descriptions of the electronic structure of molecular
and solid state systems can be used to interpret experimentally
determined spectroscopic properties (IR, Raman, EELS, UPS, XPS, SFG,
EXAFS). Although DFT can often predict relative barrier heights and
reaction energetics, it has difficulties with the prediction of absolute
values with currently available functionals. Thus, we will need to
calibrate DFT based on experimentally determined barrier heights and/or
very high level and computationally expensive ab-initio MO methods. At
the heart of catalysis is the control of chemical transformations, and
the ability to predict reaction rates is key to gaining a fundamental
understanding of catalytic processes. Thus, computational studies need
to put structure and dynamics on an equal footing. The ability to
reliably predict reaction rates is lagging behind our ability to predict
thermodynamics. This is still true for simple gas-phase processes and is
certainly true for complex reactions in solution, in the large inorganic
molecules relevant to homogeneous catalysis, and on surfaces for which
even the dynamics of molecules moving on the surface are difficult to
predict reliably. The characterization of the longtime and rare event
dynamics typical of catalyzed reactions is seriously limited for
computational approaches and presents a challenge. In some cases (e. g.,
photocatalysis and charge transfer catalysis), quantum effects in
dynamics are important and current methods are just becoming available
to treat such processes.

An overall goal of theory is to seamlessly link various approaches, from
quantum mechanics at different levels of approximation, to improved
tight-binding models for very large (100,000 atoms), to model potentials
for molecular dynamics simulations, to kinetic models, to catalysis
design optimization methods. Computational chemistry involves
calculations at the quantum, atomistic or molecular, and mesoscales, as
well as methods that form "bridges" between scales. New and promising
computational approaches are emerging, including linear scaling QM
methods, embedding techniques, improved Car-Parinello methods for
coupling molecular dynamics with electronic structure theory (DFT), new
kinetic approaches for predicting rates of reactions in solution, path
searching methods (both configurational and dynamic), kinetic Monte
Carlo sampling schemes, and evolutionary algorithms.

The direct coupling of theory and experiment is an extremely strong
combination and is needed to advance catalytic science and our
understanding of how to control chemical transformations. No experiment
reveals every detail and no calculation is perfect, but the combination
provides the most profound and detailed insights into how chemical
reactions proceed and how we can control their finest details. Among the
most demanding computational challenges are accurately solving quantum
mechanical equations for systems large enough to be of value to real
catalyst systems; extracting unifying concepts that help identify
critical parameters determining catalytic activity and selectivity; and,
using calculations for the development of systematic databases for
searching out correlations between catalytic activity/selectivity and
other materials properties.

In summary, theoretical contributions to the design of catalysts from
first principles come at many levels:

-   Modeling and understanding catalytic processes at the
    electronic/atomistic level, i.e., proposing atomic structures,
    suggesting reaction pathways, computing reaction energetics,
    modeling reaction dynamics, and identifying key parameters
    controlling a catalytic process.

-   Developing methods for bridging the large gaps in temporal and
    spatial scales that separate elementary molecular processes from the
    statistical behavior that governs chemical kinetics at the
    macroscale.

-   Identifying general trends and unifying principles common/specific
    to various classes of catalytic phenomena -- heterogeneous-,
    homogeneous-, and biocatalysis. At the level of electronic structure
    theory there is no distinction between solid, molecular and
    biological catalysts. Theory will therefore be an important
    component in the integration of the different subfields of
    catalysis. The development of a common language in heterogeneous,
    homogeneous and enzyme catalysis will have to be based on the
    fundamental properties of a catalyst determining its ability to
    activate a bond.

-   By creating databases of both theoretical and experimental results
    and developing methodologies to perform data mining and optimization
    approaches to guide design of new catalytic systems.

Given the advances that are occurring in computer systems, we can lay
out the following goals for computational catalysis:

> **50 TFlops**: accurate calculations for realistic, isolated
> homogeneous catalyst model systems (\<1.0 kcal/mol thermodynamics,
> \<50% error in reaction rates).
>
> **250 TFlops**: accurate calculations for realistic homogeneous
> catalyst model systems in solution and heterogeneous catalysts in
> vacuum (\<1.0 kcal/mol thermodynamics, \<50% error in reaction rates).
>
> **1000 Tflops**: accurate calculations for realistic homogeneous
> catalyst model systems in solution and heterogeneous catalysts in the
> presence of gases and liquids (\<1.0 kcal/mol thermodynamics, \<50%
> error in reaction rates).

The computational design of new catalysts is a key factor in enabling
the U.S. petroleum, chemical, and pharmaceutical industries to remain
competitive. Recent advances in computa­tional molecular and materials
science combined with computers that can attain usable hundreds of
teraflops can potentially increase the speed of this design process by
several orders of magnitude. These new computational capabilities will
help to revolutionize the chemical industry, turning the "art" of
catalysis creation into the "science" of catalyst design. The design of
new catalytic systems will lead to the development of new industrial
processes which are more energy efficient, use less raw materials, and
have less environmental impact.

***Dynamics and Kinetics***

Catalysts increase rates of reactions proceeding via sequences of steps
such as diffusion, bonding of reactants to catalysts, transformation of
species bonded to catalysts, and uncoupling of products from catalysts.
The temporal behavior of these steps, along with transport phenomena,
determines the overall rate of the reaction. Designing new catalysts
requires detailed information concerning these individual steps and, in
particular, which steps are "rate-limiting" so that the catalyst can be
structured to facilitate this step without negatively impacting the
other elementary steps.

The dynamic processes involve motion and energy transfer on length
scales ranging from that associated with atoms and electrons of the
substrate-catalyst combination to that of large-scale reactors. The
processes span huge ranges of time scales, from femtoseconds at the
quantum level to years in catalyst deactivation. Integration of the
dynamic processes provides a rigorous foundation for prediction of
kinetics of catalytic processes.

The capabilities for understanding and integrating these dynamic
phenomena have increased dramatically, facilitated by new experimental
and computational tools, particularly those centered in national
laboratories. Recent progress is indicated by measurements of detailed
conformational dynamics of single biomolecules. Furthermore, it is now
possible to achieve femtosecond temporal resolution and nanosecond
spatial resolution for charge transfer events.

Measurements characterizing dynamical events with exquisite space, time,
and energy resolution---even in single nano-structures---are now within
reach, and these coincide with the emerging opportunities for synthesis
of single-site catalysts, including individual nanoclusters mounted on
support surfaces that can be imaged and characterized spectroscopically.
The motions and rearrangements of the substrate and catalyst atoms can
be accounted for; inputs from single-event dynamics of these elementary
components would allow assessment of the assumptions underlying normal
averaging methods. Furthermore, advances in computational approaches may
allow us to simulate the processes directly and thereby eliminate the
need for such averaging.

Much remains to be done to consolidate the opportunities and integrate
dynamics and kinetics into catalysis by fostering collaborations between
theorists and experimentalists and setting a foundation for integration
of biological, homogeneous, and surface catalysis, which are unified by
the character of the dynamic processes.

## A Strategy of Success...Integration

As noted above, a key goal for catalysis research is the integration of
skills in a wide range of areas including catalyst synthesis, catalyst
characterization, determination of reaction pathways and the dynamics of
elementary processes, and theoretical methods for predicting the
structure of active centers and their catalytic properties. The direct
coupling of theory and experiment is an extremely strong combination and
is needed to advance catalytic science and our understanding of how to
control chemical transformations. No experiment reveals every detail and
no calculation is perfect, but the combination provides the most
profound and detailed insights into how chemical reactions proceed and
how we can control their finest details. At the level of the atom and
chemical bond, there is no distinction between solid, molecular, and
biological catalysts. The development of a common language in
heterogeneous-, homogeneous-, and enzyme catalysis will have to be based
on the fundamental properties of a catalyst determining its ability to
activate a bond. We need to integrate these different subfields of
catalysis through novel experimental and computational/theoretical
approaches. This will truly enable us to use all of the advances in the
various sub-disciplines to achieve an integrated understanding of how to
control chemical transformations.

The Department of Energy currently funds user facilities for X-ray and
neutron scattering, electron microscopy, nano-scale technology,
integrated surface science, and computation at DOE labs. These
facilities provide the strong intellectual, financial, and national
incentives for promoting catalysis science in the U.S., allowing the
design and execution of complex experiments and integration with
theoretical efforts. Coordinating the work of industry, academia, and
national labs would drive the new developments and discoveries in
catalysis that will enable the U.S. to regain its superiority and
maintain its lead in this pivotal economic engine. What remains to be
established is a mechanism for exploiting these tools for the evolution
of catalysis science. If one examines the landscape of successful
science promoted at national user facilities, one can find models for
success that can be used in managing catalysis research. A common theme
of these successful programs is the development of collaborative teams
who use the user facilities to do their own research as well as to
integrate research in a field.

***Linking Basic Discoveries with Applied Technologies***

As with other areas of science and engineering that have immediate
technological application, there is an inevitable evolution of the field
of catalysis that results from positive feedback. As basic concepts in
catalysis, have been recognized and articulated and as new catalysts
have been discovered, catalysis finds many new application areas, each
of which in turn has spawned its own set of new concepts fundamental to
their respective areas and evolved into yet more finely differentiated
application areas. The developments in fundamental science laboratories
can be translated into an industrial process, and the information gained
by industry in producing a working process helps to provide further
direction to the scientist pursuing fundamentals, in terms of important
areas of research where new concepts are needed. For example, the
discovery of homogeneous Ziegler-Natta polymerization catalysis led to
(1) the development of supported catalysts of remarkable uniformity, (2)
homogeneous catalysts that make highly linear polymer with exquisite
control of tacticity, and (3) other homogeneous catalysts that make
highly-branched polymer with essentially random stereochemistry.
Research in each of these differentiated areas is very active, with new
applications being developed for each of the different kinds of polymers
and new understanding obtained as to how the functioning of the
different catalytic sites can be altered and improved. This inevitable
evolutionary process is unplanned and largely uncontrolled, but it has
been extremely beneficial -- indeed, it is the major reason why
catalysis is so broadly used in so many different areas with such
specific advantage in each area. But this differentiation into small
specialty areas has left broad, potentially very significant areas
untouched, some areas because no one has recognized an application or
commercial incentive to drive work into these areas, others because
there has been a gap in the pace of new discoveries. Along with this
evolution, the process of discovery by basic science has shifted from
being broadly delocalized toward being more specialized into the
respective differentiated areas. Moreover, the distinction between what
constitutes a "basic" discovery in a differentiated area vs. what
becomes a valuable new application is becoming less clear.

None of the participants at the Workshop would recommend any attempt to
interrupt the current successful evolution of catalysis, to stop the
field of catalysis from accumulating ever more detailed understanding,
differentiating into ever more specialized areas, and moving more
rapidly toward practical application. There was a strong consensus that
this process has been extremely beneficial and continues to afford
exciting and important advances and opportunities. But it is also
vitally important to provide new investment to support the generation of
fundamental concepts about how to control chemical transformations and
to address challenges in catalysis that are too complex and
interdisciplinary to fit into existing funding mechanisms. The consensus
is that focusing new investment on work leading to dissolving the
traditional boundaries between molecular-, surface, and biocatalysis
will have the effect of launching just such a new generation of
fundamental concepts, concepts that will lead to new means of realizing
atom-by-atom control of catalysts and bond-by-bond control of chemical
transformations discussed in this report. This new investment also
provides an opportunity to address application areas where commercial
incentives have not kept pace with societal needs, areas such as
alternate energy and global climate change.

Along with this evolution there has been an evolution in how, and why,
catalysis research is conducted in industry. Beginning in the 1940s,
many energy and chemical companies developed in-house research programs
to build upon basic findings reported in the open literature, with the
primary goal of enabling and significantly improving large-scale
processes. This basic industrial research contributed further to the
fundamental understanding of catalysis. However, the past fifteen years
have seen marked overall decline in the scope and level of these
industrial research programs, driven by pressure to reduce costs and
remain competitive in a global economy, by the fact that further
improvements in large-scale catalytic processes have generally been of
diminishing financial return, and by the fact that many companies have
sought to de-emphasize single large-scale processes and deploy their
researchers to developing a more differentiated product base.
Furthermore, there has been an overall decline in the support of
fundamental basic research in chemistry and materials by the energy and
chemical industries. Although it is clear that industry remains well
suited to apply new basic discoveries leading to new catalysts and
catalytic processes for our economic and social benefit, industry is no
longer so well suited to generate the ideas that lead to improvements in
catalytic applications. These ideas often arise from research undertaken
with a longer range and more fundamental outlook, and possibly with a
very different specific application or process initially in mind (or
none at all!), research of a nature that most companies now find
difficult to justify. The difficulty is compounded by the fact that each
sub-discipline of catalysis has evolved its own set of specialized and
expensive techniques requiring highly skilled scientists, so that
companies hoping to merge concepts and approaches from different
sub-disciplines to address problems at the multidisciplinary interface
-- exactly where catalysis has some of its most exciting opportunities
-- are confronted with an especially daunting staffing, equipment, and
funding challenge.

There has also been an evolution in fundamental research in catalysis as
a collaborative discipline. Traditionally, the dominant paradigm for
catalysis research in the United States has been that fundamental
studies and many longer-reaching discoveries tend to originate from
government-funded research in academic and national laboratories,
inspired by curiosity, convergence of scientific opportunity, or
societal need. Traditionally, the drive toward application has been
taken up by industrial laboratories as their scientists try to connect
discoveries reported in the literature with commercial opportunities.
Collaboration between academic and national laboratories, where the
instrumentation and funding infrastructure is focused on fundamental and
longer-range research, and industrial laboratories, where the
infrastructure is more focused on problem solution and commercial
applications, has always represented an excellent opportunity to move
fundamental knowledge and understanding into practical application to
solve problems and advance new technologies. But although there are many
recent examples of fruitful collaborations between basic and applied
researchers in catalysis, some resulting in startup companies and others
resulting in joint publications, most collaborations have been limited
to simply hiring a student from a particular academic group that has
developed a basic idea by a company that hopes to exploit it. This
latter practice continues to dominate because of the need for ownership
of intellectual property (IP) that is inherent to industry. It has been
especially difficult in catalysis, where it may not be the exact
catalyst that can be patented, but instead the process in which it is
used, which may or may not be patentable.

In view of these trends, how can we ensure that research and development
in catalysis will allow society to meet the critical challenges it
faces, including (a) enhanced energy efficiency with low-cost fuels that
produce lower harmful emissions, (b) the elimination of polluting
by-products, (c) enhanced homeland security and stockpile stewardship,
(d) effective synthesis of new and improved drugs, and (e) new materials
with tailored properties? Federal funding agencies, the Department of
Energy, in particular, can positively influence the evolution of the
field of catalysis. By articulating the importance of catalysis,
sponsoring workshops, maintaining national facilities, continuing and
bolstering funding for fundamental research in catalysis, and
emphasizing multidisciplinary Grand Challenge research the DOE can
minimize risks that broad, potentially very significant areas of
catalysis research are left untouched, some areas because no one has
recognized an immediate application or commercial incentive to drive
work into these areas, or because there has been a gap in the pace of
new discoveries.

***National Facilities and Capabilities***

The DOE, specifically BES, uniquely provides the support for the large
national user facilities such as synchrotrons and light sources, neutron
scattering facilities and the new nanoscience facilities that enable
scientists to perform experiments with equipment that is too expensive
for an individual investigator or even a university to own or is too
complicated for a single research group to manage. As noted above,
catalysis, especially catalysis at single sites (e.g. nanoparticles)
represents the ultimate challenge for characterization, and a wide
variety of techniques have been adapted or developed to address it. For
many of these characterization techniques a research team needs to be
able to make its own measurements in its own laboratories or at its
local institution. However, techniques requiring synchrotron radiation
and neutron beams can only be employed at national laboratory
facilities, because the necessary instruments are so expensive,
specialized, and demanding of space and expertise that it is only as
national resources that they can be made available. For reference, table
A \[p. 78 of the White Report, attached\] outlines some of the
techniques that use synchrotron radiation and neutron beams along with
their particular applications to catalysis research. A table cannot
fully convey the power of these techniques nor the value of the
information they provide about catalytic sites and processes. Insert A
\[p 55 of the White Report, attached\] provides a better illustration of
how these techniques enable atomic-detail pictures of actual binding and
catalytic site environments in complex solid systems.

Table 1. Applications of Synchrotron Radiation and Neutron Scattering
Methods for the catalysis research.

![](media/image3.png){width="5.4840277777777775in"
height="4.950694444444444in"}

> ![](media/image4.png){width="5.385416666666667in"
> height="6.052083333333333in"}

But the power and value of using these national facilities do not come
without constraints. The national facilities serve many user
communities, and access to them is in high demand. Access to the
facility is controlled by a proposal system at an individual facility,
which often leads to a gap of at least several months between the
generation of an idea and the experiment or between different
experiments. Obviously these constraints apply to each user, but they
are especially troublesome to researchers in catalysis. Catalysis, by
its very nature, involves subtle and transient effects. Due to the
instability of many catalysts and their sensitivity, the catalytic
activity of a sample may be lowered or absent when beam time to study it
finally becomes available, and it is often nearly impossible to
anticipate in advance the exact experimental conditions to which a
particular catalyst sample will best respond. Furthermore, specialized
cell designs are often needed for *in-situ* studies, and many facilities
are poorly equipped for handling the pressures and temperatures needed
to study working catalysts. As a result many catalysis researchers view
gaining access to national facilities, for example, beam time, as a
high-risk endeavor with uncertain reward and do not seek it, choosing
instead to limit their work so that the only questions being asked are
the ones that can be answered using their own instruments. Although
understandable, this situation is unfortunate and does not lead to the
best science that can be done with current instrumentation. Moreover,
many researchers in catalysis science are not aware of all of the
capabilities available at the national facilities and how they can be
used to address the specific question an individual researcher is trying
to answer. As partial remedies and as means of encouraging an expansion
of the catalysis user community, we recommend the following:

-   Increase the number of dedicated neutron and synchrotron beamlines
    to support research by the catalysis community, and develop
    mechanisms to enable researchers to get rapid and continued access
    to beam lines for exploratory studies.

-   Support scientific staff members at the facilities who are experts
    in the facility and the experimental techniques, and will become
    expert in catalysis studies, to facilitate all phases of user
    research especially for first-time users of the facilities.

-   Maintain sample cells and end stations suitable for *in-situ*
    catalyst study, equip beamlines for controlled-atmosphere sample
    preparation and manipulation, and provide computational facilities
    at the end stations to enable preliminary data interpretation.

-   End stations at beam lines are one part of such facilities, but
    other capabilities including mass analyzers, gas chromatography,
    *etc*. are needed that complement the radiation-based probes of the
    light or neutron source.

-   Ancillary devices for beamlines need to be funded to allow *in-situ*
    measurements at neutron and light sources.

-   Provide outreach programs to educate the catalysis community about
    facilities, procedures, and new developments, and to encourage
    suggestions from the catalysis community for facility improvements.

-   Provide and publicize sabbatical and visiting-scholar programs to
    enable extended stays at the facilities.

-   Explore means of remotely accessing data and controlling experiments
    where possible, to minimize user travel.

-   Provide housing for minimum living costs of visitors at the
    facilities.

Whereas the emphasis above has been on access to beam lines, access to
high-end computational resources and nanofabrication facilities is
needed equally at national user facilities. High-end computation is
enormously important to understanding how and why catalytic processes
occur, as discussed in Section III. D. Nanofabrication is beginning to
be used in catalysis research, and general relationships between
nano-structure and catalysis are summarized in Section II.A. Of course,
for these relationships to be explored and exploited, the
nano-structures must somehow be made, ideally not as single specimens
but rather as arrays of thousands of replicas whose catalytic properties
will be much easier to measure. The means by which research teams access
nanofabrication facilities are still evolving, but they currently tend
to be "work for hire," with the research teams providing the design and
specifications and the facilities fabricating according to that design.
This mode will be adequate for many research programs, but some research
teams will undoubtedly require that nanofabrication capabilities be more
interactively integrated with their catalysis research.

Because of the need for many different, often expensive experimental
approaches coupled with advanced computational resources to advance
catalyst science, we need to strengthen interactions between the
catalysis community and the user facilities that offer the best tools
available. A key need for the catalyst community is the capability to
have access to novel materials, for example metal oxides with a
controlled site size and distribution that is reproducible, that can be
used in gaining a fundamental understanding of how catalysts work. One
then has to be able to characterize the materials as pristine systems
and study them in isolation as well as under realistic catalytic
operating conditions. These requirements define the need for
well-instrumented reactors with diagnostic measurement tools with the
required spatial and temporal resolution. Furthermore, new, expensive
tools, for example, PEEM with femto-second lasers, TEM tomography
systems, high-performance computers, and NMR/ESR tomography systems need
to be made available to the catalyst community to provide the temporal
and spatial resolution needed to make real advances. The cost of such
instrumentation and capabilities as well as their support can easily be
too large for a single investigator or university to support, and so
national user facilities are needed. Having capable scientific staff
that can support and run complex apparatuses on a wide range of problems
is something that a national user facility often does well. Such a user
facility(-ies) would enable catalyst researchers to have access to
state-of-the-art instrumentation that they define the need for as well
as to have access to expertise about other advanced instrumentation that
can be brought to bear on addressing the fundamental questions in
catalytic research. For the catalysis community to fully realize its
potential, the capability to have such tools and materials deployed for
catalyst research is essential. Furthermore, an integrated catalysis
capability using different facilities and capabilities in a coordinated
effort would serve as a focal point of intellectual capital in the
catalysis community. The coordinated effort would encourage
cross-fertilization and breaking down the walls between the
sub-disciplines of catalysis science, for example, by participation of
scientists in workshops and conferences and by providing an environment
where faculty, students, postdocs, national laboratory scientists, and
industrial scientists can work on related, fundamental problems in
catalysis and the control of chemical transformation.

***A National Agenda for the Future***

The United States has a history of leadership in catalysis research with
strong roots in the entrepreneurial spirit of federally sponsored
individual research coupled with strong interactions with US industry.
That leadership has come into question. The refocusing of U.S. industry
to shorter term problems more strongly directed at production issues
with a resulting decline in basic research in industry has placed the US
leadership role in jeopardy as highlighted in the National Academy of
Sciences' report "Experiments in International Benchmarking of U.S.
Research Fields", National Academy Press (2000).

That catalysis science is a critical component of the Nation's economic
and energy security future has been amply demonstrated by numerous
studies such as the Pimentel Report "Opportunities in Chemistry",
National Academy Press (1985); the Amundsen Report "Frontiers in
Chemical Engineering", National Academy Press (1988); the Bell Report
"Catalysis Looks to the Future", National Academy Press (1992), along
with a number of workshop reports such as "Carbon Management:
Implications for R&D in the Chemical Sciences" National Academy Press
(2001) and the soon to be released reports from the Basic Energy
Sciences Advisory Committee's workshop on Energy Security. It is an
underpinning science for many present and future technology needs as
highlighted in the soon to be released study on the Nation's needs for
the science that supports our Energy Security. The Nation's need for the
knowledge catalysis research can provide is real and urgent, but it is
not currently being met either within the Federal Sector or the Private
Sector. The role of the federal sector is critical in setting the agenda
for the 21^st^ century. It must identify and support research that will
provide the foundations for evolving the current scientific
infrastructure into one that will meet the ever changing needs of the
new century and beyond.

The federal research agenda for the new century must focus on challenges
sufficiently grand to drive our infrastructure in directions to meet the
uncertainties of the future. One such challenge grand enough to have
broad impact on our scientific infrastructure is developing an
understanding at the molecular level that will allow us to manipulate,
to predict and ultimately to control chemical reactivity. Catalysis is
one of the sciences at the heart of this challenge.

However, for catalysis science to meet this challenge we will have to
change the text books and evolve our understanding well beyond the
classical "pixy dust" definition - "Catalysts are substances that can
speed up chemical reactions and yet remain unchanged at the end of the
reaction" - that beginning students in the chemical sciences learn. To
accomplish this it will be necessary to build on the country's strength
in individual research and to establish competitive teams from those
disciplines that contribute towards evolving research programs, like
catalysis, whose roots cross many disciplines such as biochemistry,
materials sciences, chemistry and chemical engineering.

Appendix A (Workshop Agenda)

DOE Workshop on Opportunities for Catalysis/Nanoscience

Tuesday, May 14, 2002

8:00 AM Charge to participants -- Bill Millman and Mike White

8: 30 AM Plenary Talk -- John Frost (Michigan State University)

8:45 AM Plenary Talk --Wayne Goodman (Texas A&M University)

10:15 Break

10:30 to end of day

Breakout sessions:

T1. Catalyst design driven by fundamental research -- Mark Barteau

T2. Biocatalysis -- John Frost

T3. National Facilities -- photons, neutrons, end stations -- Chun Loong

T4. Tuning reactivity by tailoring nanostructures -- Wayne Goodman

T5. Dynamics -- Bruce Kay and Mike White

6:30PM Dinner

Wednesday, May 15, 2002

8: 30 AM Plenary Talk -- Jens Norskov (Michigan State University)

8:45 AM Plenary Talk --Tobin Marks (Northwestern University)

10:15 AM Break

10:30 to end of day (when the task is finished)

Breakout sessions:

W1. Linking basic research to applications---Simon Bare and Alex Bell

W2. Homogeneous systems---John Bercaw

W3. Spatially resolved and atom specific microscopy and spectroscopy --
Steve Pennycook.

W4. Theory -- Roberto Car

W5. Synthesis of nanostructured materials for catalytic applications --
Peter Stair

Thursday, May 16, 2002

8:00 AM to Noon -- Reports from breakout sessions (10) -- 20 minutes
each. (Participants other than breakout chairs and whoever they choose
to work with them are free to depart at noon.)

1 PM onward -- Breakout session chairs meet with Mike White and Pam Cook
(who will edit the report). Recognizing that a full report will be
provided to DOE by end of July, 2002, there is little time to bring
deliverable to its final \"first-class\" form. A single breakout room is
being held for Friday morning -- the chair (White) would like to finish
Thursday afternoon but seeks cooperation to remain if necessary to agree
on and develop a very good draft report.

Proposed breakout assignments

Tuesday, May 14, 2002

Proposed breakout Session Barteau, Mark

Name Tues

Baker, Tom T1

Barteau, Mark T1

Bercaw, John T1

Carrado, Katie T1

Fleisch, Theo (1) T1

Gaffney, Ann T1

Gai, Pratiba T1

Gorte, Ray T1

Iton, Lennox T1

Mavrikakis, Manos T1

Norskov, Jens T1

Ott, Kevin T1

Hall, Rich T1

Xantheas, Sotiris T1

Rauchfuss, Tom T1

Pennycook, Steve T1

Bullock, Morris T1

Proposed Breakout Session Frost, John

Name Tues

Cameron, Doug T2

Coates, Jeff T2

Frost, John T2

Hartrwig, John T2

Ingram, Lonnie T2

Keasling, Jay T2

Rappe, Anthony T2

Selloni, Annabella T2

Tumas, Bill T2

Wang, George T2

Wood, Tom T2

Yeung, Ed T2

Zhao, Huimin T2

Grubbs, Robert T2

Proposed Breakout session Loong, Chun

Name Tues

Antonio, Mark T3

Bare, Simon T3

Bell, Alex T3

Peden, Chuck T3

Eckert, Juergen T3

Hwang, Robert T3

Kao, Chi-Chang T3

Kemp, Rick T3

Loong, Chun T3

Mullins, David T3

Nilsson, Anders T3

Pantelides, Sokrates T. T3

Rostrop Nielsen, Jens T3

Teller, Raymond T3

Tuinstra, Richard T3

Proposed breakout session Goodman, Wayne

Name Tues

Dai, Sheng T4

Datye, Abaye T4

Gates, Bruce T4

Goodman, D. Wayne T4

Henderson, Michael T4

Hrbek, Jan T4

Krische, Mike T4

Marks, Tobin T4

Mims, Charles T4

Nemantsverdriet, J. W. T4

Perry, Scott T4

Tsapatsis, Michael

T4

Wu, Ruqien T4

Yaghi, Omar T4

Proposed Breakout Session Kay, Bruce and White, Mike

Name Tuesday

Chen, Donna T5

El Sayed, Mostafa T5

Gellman, Andrew T5

Petek, Hrvoje T5

Car, Roberto T5

Jonsson, Hannes T5

Klein, Michael T5

Lauterbach, Jochen T5

Mullins, Buddie T5

Schmidt, Lanny T5

Stair, Peter T5

Teplyakov, Andrew T5

White, J. M. T5

Kay, Bruce T5

Proposed breakout assignments

Wednesday, May 15, 2002

Proposed Breakout session \-- Bell, Alex and Bare, Simon

Name Wed

Bare, Simon W1

Bell, Alex W1

Cameron, Doug W1

Fleisch, Theo (1) W1

Gaffney, Ann W1

Gorte, Ray W1

Iton, Lennox W1

Mims, Charles W1

Mullins, David W1

Ott, Kevin W1

Rostrop Nielsen, Jens W1

Hall, Rich W1

Tuinstra, Richard W1

Proposed Breakout session Bercaw, John

Name Wed

Baker, Tom W2

Bercaw, John W2

Coates, Jeff W2

Frost, John W2

Hartrwig, John W2

Ingram, Lonnie W2

Tumas, Bill W2

Wang, George W2

Wood, Tom W2

Zhao, Huimin W2

Grubbs, Robert W2

Bullock, Maurice W2

Kemp, Rick W2

Loong, Chun W2

Krische, Mike W2

Marks, Tobin W2

Proposed Breakout session Pennycook, Steve

Name Wed

Gai, Pratiba W3

Pennycook, Steve W3

Eckert, Juergen W3

Kao, Chi-Chang W3

Nilsson, Anders W3

Teller, Raymond W3

Datye, Abaye W3

Gates, Bruce W3

Nemantsverdriet, J. W. W3

Chen, Donna W3

Petek, Hrvoje W3

Lauterbach, Jochen W3

Antonio, Mark W3

Hwang, Robert W3

Proposed Breakout Session Car, Roberto

Name Wed

Mavrikakis, Manos W4

Barteau, Mark W4

Norskov, Jens W4

Xantheas, Sotiris W4

Rappe, Anthony W4

Selloni, Annabella W4

Pantelides, Sokrates T. W4

Goodman, D. Wayne W4

Hrbek, Jan W4

Wu, Ruqien W4

Car, Roberto W4

Klein, Michael W4

Proposed breakout session Stair, Peter

Name Wed

Carrado, Katie W5

Rauchfuss, Tom W5

Keasling, Jay W5

Yeung, Ed W5

Dai, Sheng W5

Henderson, Michael W5

Perry, Scott W5

Tsapatsis, Michael W5

Yaghi, Omar W5

El Sayed, Mostafa W5

Gellman, Andrew W5

Mullins, Buddie W5

Schmidt, Lanny W5

Stair, Peter W5

Teplyakov, Andrew W5

White, J. M. W5

Kay, Bruce W5