# Research Activity: Catalysis and Chemical Transformations

Division: Chemical Sciences, Geosciences, and Biosciences

Primary Contacts: Raul Miranda
([Raul.Miranda@science.doe.gov](../Raul.Miranda@science.doe.gov);
301-903-8014)

Paul H. Maupin
([Paul.Maupin@science.doe.gov;](mailto:paul.maupin@science.doe.gov;)
301-903-4355)

Team Leader: John C. Miller

Division Director: Eric Rohlfing (Acting)

**Portfolio** **Description:**

This activity supports basic molecular-level research to understand
chemical catalysis and electrocatalysis, and to develop principles and
predictive methods for the rational design of catalysts. It encompasses
all types of catalysts for organic and inorganic synthesis and
transformation reactions, including organometallic complexes, hybrid
organic-inorganic compounds or porous solids, bio-inspired catalysts,
interfaces of metals, semiconductors and non-metallic compounds such as
oxides, carbides, and nitrides. Special emphasis is placed on
nanocatalysis, to understand and use the enhanced catalytic properties
that emerge at the nanoscale. Its research portfolio addresses catalytic
model systems of relevance to fossil and renewable energy production,
storage, and use; environmental remediation; materials synthesis; fuel
cell reactions; and photocatalytic conversions. It promotes the use and
the co-development of advanced synthetic, spectroscopic, and theoretical
techniques that pertain to the intrinsic needs of catalysis research,
such as complex but controllable compositions and structures and wide
scales of time and space resolution. Nanoscale design, multiscale
theory, modeling and simulation, and femtosecond and synchrotron-based
spectroscopic techniques present unique opportunities for the
acquisition of new knowledge in catalysis. This activity is the nation's
major supporter of catalysis research as an integrated multidisciplinary
activity, assembling a body of researchers from several branches of
science.

**Unique Aspects:**

This activity funds the largest fraction of basic research in catalysis
in the federal government. It seeks to cross the barriers between
heterogeneous, homogeneous, and bio catalysis. The integration promotes
synergism among disciplines and innovation in fundamental approaches as
well as applications. In terms of instrumentation, this program has
helped with the establishment of surface science and inorganic synthesis
laboratories at universities and encourages the use of large-scale
facilities at the Department of Energy (DOE) national laboratories.
Principal investigators use synchrotron, neutron and electron sources
and computational tools to significantly advance catalysis research.

**Relationship to Other** **Programs:**

This activity relates to other activities within BES. The Catalysis and
the Chemical Physics activities have complementary goals in the areas of
surface science, surface chemistry, and quantum mechanical theory,
molecular modeling, and simulation of catalytic-related phenomena. The
Catalysis and Photochemistry activities also complement one another in
the support of fundamental photocatalysis and photoelectrocatalysis,
which are relevant to solar photoconversion and photochemical synthesis.
The Catalysis and Separations activities share their concern and in some
instances co-support synthetic research for zeolitic, mesoporous,
hybrid, and caged materials. The Catalysis and Heavy Elements Chemistry
activities also share interest in the design and synthesis of ligands
and coordination compounds of lanthanides. The BES synchrotron
facilities have beamlines used by Catalysis researchers, in particular
the National Synchrotron Light Source (NSLS), Advanced Photon Source
(APS), Intense Pulsed Neutron Source (IPNS), and Advanced Light Source
(ALS). The BES Nanoscale Science Research Centers (NSRCs), in particular
the Center for Functional Nanomaterials (CFN) and the Center for
Nanophase Materials Sciences (CNMS), also have thrust areas that address
catalysis research, and hence share some of the Catalysis activity
goals.

Within DOE, the activity of Catalysis produces research outcomes of
relevance to programs of the Office of Energy Efficiency and Renewable
Energy and the Office of Fossil Energy. These programs have collaborated
during the review of proposals in relevant initiatives, such as the
Hydrogen Fuel Initiative.

The activity is coordinated with other federal agencies. At the National
Science Foundation (NSF), heterogeneous and bio catalysis are funded
within its Engineering Directorate while homogeneous catalysis is funded
within the Math and Physical Sciences Directorate (Organometallic and
Inorganic Chemistry program). Also at the NSF, the surface science and
materials aspects of catalysis are spread among three divisions
(Chemistry, Materials, and Chemical and Transport Systems). The National
Institutes of Health (NIH) funds the health-related applications of
homogeneous, enzymatic, and bio catalysis; the Environmental Protection
Agency (EPA) funds the application of catalysis to environmental
remediation; and the Office of Naval Research (ONR) and Army Research
Office (ARO) support the application of catalysis to military purposes.

**Significant Accomplishments:**

The science and practice of catalysis over the last several decades have
led to many achievements of fundamental interest. A significant
contribution has been made to the current molecular-level understanding
of catalytic cracking of hydrocarbons in zeolites, reforming of
hydrocarbons over supported bimetallic alloys, and desulphurization of
heteroaromatics over supported metal sulfides. Reactions of importance
in environmental chemistry, such as removal of NO~x~, have been studied
in detail over model single crystal metals and supported metals. Results
of those investigations have dramatically improved the knowledge of
catalyst structure-reactivity relationships. This activity has also led
to fundamental advances in the catalysts required for the selective
oxidation of hydrocarbons for the manufacturing of monomers, fine
chemicals, and fuel additives. During the past decade, one of the most
significant accomplishments in homogeneous catalysis was the development
of novel single-site metallocene catalysts for polymerization of
alkenes. The control of polymer tacticity resulted in property
enhancement and a largely expanded use of polyalkene plastics, from
extending the shelf life of food we buy to enhancing the efficiency of
the cars we drive. Other very significant achievements were the
catalytic synthesis of organic acids by alcohol carbonylation and the
generation of important monomers by olefin metathesis. More recently,
the selective oxidation of C-H bonds was achieved both homogeneously and
heterogeneously. For their achievements, researchers in this program
have been widely honored by scientific societies, as they have received
three-quarters of the awards in Organometallic Chemistry given by the
American Chemical Society, all but one of the fundamental catalysis
awards given to U.S. academics by the North American Catalysis Society,
And several international awards, including the Nobel Prize in Chemistry
for 2006.

**Mission Relevance:**

Catalytic transformations impact virtually all of the DOE energy
missions. Catalysts are needed for all of the processes required to
convert crude petroleum and natural gas into clean burning fuels.
Catalysts are crucial to energy conservation in creating new,
less-energy-demanding routes for the production of basic chemical
feedstocks and value-added chemicals. Catalytic science has impacted the
technology used to clean up environmental pollutants, such as unwanted
products from chemical production or from combustion, or by transforming
toxic chemicals into benign ones, such as chlorofluorocarbons into
environmentally acceptable refrigerants.

**Scientific Challenges:**

The grand challenge for this area of research is the *a priori*
molecular-level design and synthesis of catalysts with controlled
reactivity and durability. Such knowledge is of relevance for the
production of catalysts that convert natural resources into energy or
desired products in an energetically efficient and environmentally
benign manner. That challenge can be met by coordinating fundamental
research on chemical synthesis, structural characterization, mechanistic
studies, and theoretical interpretation.

The current challenge in inorganic synthesis is the atomistic and
molecular control of structure, shape, and functionality, all of which
can be facilitated by the development of libraries of modular ligands.
For the particular case of biomimetic catalyst development, synthesis
and use of versatile ligands must be promoted. Likewise, air- and
water-resistant complexes must receive priority. The control of
macromolecular structure continues to be a challenge. Secondary
structures that produce shape-selective reaction environments must be
attained by the use of, for example, dendrimers, polypeptides, zeolites,
and imprinted media.

In solid state synthesis, the current frontier is to produce catalytic
materials with nanoscale control of composition, homogeneity, shape, and
structure. A challenge is to design molecular precursors and convert
them into solid-state structures with desired chemical functionalities
that are durable under reaction conditions. Traditional routes of
surface chemistry, aqueous-solution chemistry, and high-temperature
chemistry need to be complemented by softer routes. For example,
coordination chemistry may be used to build nanoparticles that are
surface-functionalized with metal compounds. Organic or biological
strategies may then be used to arrange the particles into preconceived
patterns. These arrangements will provide molecular recognition
properties (for example, size, shape, chirality, and hydrophobicity).

The characterization of synthetic catalysts demands higher spatial and
time resolution under *ex situ* and *in situ* conditions. Both
electronic and atomic structures must be correlated with secondary and
macrostructure and their time-resolved evolution. The kinetically
significant intermediates must be identified and discriminated from
those species or moieties that contribute to selectivity and from those
that are merely inactive. This is a particularly crucial need in
solid-mediated catalysis and biocatalysis.

The study of reaction mechanisms will be promoted by the synergistic use
of theory, simulation, and experimentation. In particular,
identification and structural characterization of the transition states
still remains a challenge for most reactions. Classical labeling,
trapping and molecular probe experiments must be complemented with
time-resolved *in-situ* spectroscopy in order to acquire information on
bonding dynamics. The development of chemo-, regio-, and
stereo-selective reactions is of primary importance to the advancement
of the science of catalysis, since those reactions present the highest
demands on catalysts. Conformers at equilibrium are usually separated by
barriers of less than 3 kcal/mol. While high selectivity has been
obtained with homogeneous catalysts in selected instances, heterogeneous
catalysts require substantially more study, possibly with help from
biomimetics.

Catalysis of bond cleavage and reformation has, for the most part, been
restricted to hydrocarbons (CC, CH bonds), halogenated compounds (CX
bonds), and nitrogen and sulfur containing compounds (CS, CN bonds).
Moreover, past and current research has also addressed the selective
addition of oxygen, hydroxyl, or nitrogen to hydrocarbon and aromatics.
For homogeneous catalysis, the challenge is to carry out these selective
reactions under solvent-less conditions or with green solvents such as
supercritical CO~2~, while maintaining stability. For heterogeneous
catalysis, the challenge is to work at low temperature and pressure
conditions with high activity and selectivity. For both types of
catalysis, a major challenge is to obtain selective conversion for
reactants such as short-chain saturated hydrocarbons and other
refractory molecules. Likewise, new challenges for all types of
catalysts have arisen in activating molecules and materials derived from
biorenewable resources.

Besides hydrocarbon chemistry, other challenges reside in the
elucidation of the catalytic mechanisms for the synthesis of molecular
and nanomaterials. For example, in the catalytic synthesis of carbon
nanotubes, chirality control has remained elusive because of lack of
understanding of the structure-determining steps. As another example,
the nucleation and subsequent growth of silicon nanowires from silane or
its derivatives on molten gold nanoparticles proceed through catalytic
pathways that must be understood. Finally, the synthesis of compound
semiconductors and more complex nanomaterials constitute an excellent
challenge for the development of catalytic science and its application
to a new area.

**Funding Summary:**

Dollars in Thousands

[FY 2005]{.underline} [FY 2006]{.underline} [FY 2007]{.underline}
[Request]{.underline}

37,871 38,107 47,459

> [Performer]{.underline} [Funding Percentage]{.underline}
>
> DOE Laboratories 58 %
>
> Universities 38 %
>
> Other 4 %

### 

These are percentages of the operating research expenditures in this
area; they do not contain laboratory capital equipment, infrastructure,
or other non-operating components.

The laboratory programs are multi-investigator efforts and make use of
specialized facilities at Lawrence Berkeley National Laboratory,
Brookhaven National Laboratory, Oak Ridge National Laboratory, Argonne
National Laboratory, and Ames Laboratory, usually involving
collaborators from universities.

**Projected Evolution:**

The science of catalytic chemistry is still emerging. A wealth of
experimental information has been accumulated relating catalytic
structure, activity, selectivity, and reaction mechanisms. However, for
phenomenological catalysis to evolve into predictive catalysis, the
principles connecting those kinetic phenomena must be more clearly and
thoroughly identified.

Better understanding of the reactivity of matter will result from more
complete integration of experiment and theory, reproducible synthesis of
catalysts, and thorough characterization of catalysts and reactions. An
effort is needed to promote scientific cooperation among groups with
complementary expertise in synthesis, structural characterization,
intermediate and transition state characterization, dynamics simulation,
and kinetics determination. National laboratories or university centers
may serve as focal points for knowledge integration.

Following from the specific scientific challenges outlined above, it has
become apparent that the convergence of heterogeneous, homogeneous, and
biocatalysis must be promoted. Ideas and approaches motivated by
biological reaction systems will be used to derive new biomimetic homo-
or heterogeneous analogues. For example, two such particular ideas are
the use of long-range or secondary structure to affect not just
selectivity but also activity of inorganic catalysts, and the use of
tunable structural flexibility to affect reaction pathways and hence
selectivity.

New single investigator efforts are expected to be focused on the
challenges mentioned. The following examples illustrate the areas where
mechanistic understanding and new methodology are needed: (a) synthesis
of hybrid organometallic-heterogeneous catalysts from molecular
precursors such as organometallic or cluster compounds or
organic-inorganic host-guest complexes; (b) synthesis of mixed metal
inorganic compounds and derived high-temperature catalysts consisting of
crystalline nanoporous structures with precisely positioned chemical
functions; (c) selective functionalization of saturated hydrocarbons or
stereoselective functionalization of complex molecules by heterogeneous
catalysis; (d) characterization of kinetically relevant intermediates
and catalyst dynamics with high spatial and time-resolution and *in
situ* spectroscopy, microscopy and diffraction, and in particular, with
synchrotron and neutron-based techniques and advanced computational
techniques; (e) environmentally benign transformations using
solvent-less homogeneous catalysis, low-temperature heterogeneous
reactions, and tandem or programmable catalysis, i.e., precise matching
of functionalities among dissimilar catalysts.