Low temperature CO oxidation kinetics by dendrimer templated supported Au catalysts

Supported nanoparticle catalysts have been key players in technologies tied to energy production, utilization, and emissions abatement. Classic examples of include platinum metal reforming catalysts, fuel cell catalysts, and the automotive catalytic converter. Although supported nanoparticle catalysts are readily prepared by standard impregnation techniques, active sites are not necessarily well characterized or well understood. Our work is directed towards preparing supported catalysts from nanoparticles prepared using new solution synthetic techniques. In this presentation, we discuss the preparation of supported Au catalysts using PAMAM dendrimers as nanoparticle templates. Finely dispersed nanoparticles (1.3 +/- 0.3 nm) can be prepared via this route, deposited onto a commercial titania, and activated to yield highly active heterogeneous catalysts. The new catalysts were characterizes and evaluated for low temperature (263-293 K) CO oxidation activity, which is an important process for cleaning hydrogen fuel streams for fuel cell applications. Analysis of oxygen saturation curves and competition experiments at low conversion (< 2%) provided a detailed kinetic characterization of the new materials and allowed for comparisons to a standard gold catalyst.