Heterogeneous Catalysis Research at the University of Kentucky

M. A. Keane (Department of Chemical and Materials Engineering,
University of Kentucky, Lexington, KY 40506)

Abstract No.: keane154

On-going catalysis research projects focus on two topics.

***1. Environmental Catalysis***

Volatile organic compounds (VOCs) are established sources of
environmental pollution and increasingly stricter legislation is being
introduced to reduce VOC emissions. To date, combustion has been the
favoured means of VOC abatement but this approach generates unwanted
CO~2~, does not adequately suppress emission of halogenated compounds
and the products of incomplete combustion can be more toxic than the
initial feedstock. We are actively investigating the application of
catalytic hydrogen treatment as an alternative pollution control
methodology. Such a procedure has lower energy requirements and
generates non-environmentally hazardous, reusable products. We have
studied the catalytic hydrogenolysis of a range of aromatics,
established VOCs^1^, using well-characterised supported metal catalysts.
This work has been extended to the treatment of hazardous chlorinated
compounds^2-4^. The respective roles of reaction temperature, reactant
concentration, contact time and catalyst structure are under
investigation. The nature of the chlorinated VOC/catalyst interaction
and modifications to the electronic structure of the metal sites are
poorly understood but these issues are critical in optimising catalytic
activity/selectivity.

***2. Growth of Highly Ordered Carbon via Catalysis***

As part of the above environmental catalysis program, we have been
examining the nature of metal/Cl interactions by contacting a freshly
activated Ni/SiO~2~ directly with HCl followed by reaction. A dramatic
loss of activity results and this is quite unexpectedly accompanied by a
growth of carbon filaments from the surface of the catalyst^5^. A search
through the literature has revealed similar carbonaceous growths
involving either arc discharge or the catalytic decomposition of
hydrocarbons but every reported route typically requires temperatures in
excess of 723 K. In our system, the catalytic step leading to carbon
growth was conducted at 553 K. Preliminary high resolution TEM analysis
of these novel carbon materials has shown that they possess well-defined
graphitic structures. Work is now on-going to fully characterise these
materials.

References

1\. **M.A. Keane**, "The Hydrogenation of o-, m- and p-Xylene over
Ni/SiO~2~", **J. Catal.** **166**, *347*, 1997.

2\. E.-J. Shin and **M.A. Keane**, "Gas Phase Catalytic
Hydrodechlorination of Chlorophenols Using a Supported Nickel Catalyst",
**Appl.** **Catal. B: Environmental** **18**, *241*, 1998.

3\. E.-J. Shin and **M.A. Keane**, "Detoxifying Chlorine Rich Gas
Streams Using Solid Supported Nickel Catalysts", **J. Hazard. Mater. B**
**66**, *265*, 1999.

4\. E.-J. Shin, A. Spiller, G. Tavoularis and **M.A. Keane**,
"Chlorine/Nickel Interactions in Gas Phase Catalytic
Hydrodechlorination", **Phys. Chem., Chem. Phys.** **1**, *3173*, 1999.

5\. C. Menini, C. Park, R. Brydson and **M.A. Keane**, "Growth of Highly
Ordered Carbon Filaments During the Catalytic Hydrodechlorination of
Chlorobenzene at 553 K", **J. Phys. Chem. B**, **104**, *4281*, 2000.