The Synthesis of Noble Metal Bimetallic Catalysts Via Electrostatic Adsorption

Noble bimetallic catalysts are ubiquitous in academia and industry. A survey of the last decade of catalysis literature reveals over two hundred articles and a similar number of patents pertaining to bimetallic systems comprised of two noble metals, with predominant applications in air pollution abatement, petroleum refining, Fischer Tropsch synthesis, as well as fuel cell catalysts for both reactions occurring at the anodes and cathodes.  More than 50% of the literature surveyed, however, employed dry impregnation to synthesize bimetallic catalysts.  When using dry impregnation, the intimate interaction of the two cannot be well controlled and usually occurs only to a minimal extent.  Furthermore, metal particles are often agglomerated and poorly dispersed. 

In this talk we present several simple, rational, scalable methods to prepare supported bimetallic particles with high dispersion and intimate metal1-metal2 interaction.  The points of zero charge of many pure noble metal oxides has been measured for the first time, as well as adsorption surveys of other noble metal complexes onto the bulk noble metal oxides.  With this information we demonstrate how electrostatic adsorption can be used to synthesize well dispersed noble bimetallic nanoparticles that are either homogeneously alloyed or exist in core-shell morphologies.