Platinum Monolayer Electrocatalysts for Methanol Oxidation

Abstract

The direct methanol oxidation fuel cell (DMFC) yields great promise as a power source. It reached that stage as a result of extraordinary contributions of Shimshon Gottesfeld, whom we are honoring by this issue of JES. We briefly comment on his main contributions and, in this context, we present new catalysts for methanol oxidation. They comprise a platinum monolayer (Pt_ML) under tensile strain that produce a large enhancement in the catalytic activity. Pt_ML/Au(111), where Pt_ML is stretched by over 4%, displayed a significantly enhanced activity. The tensile strain induced by Au(100) has a similar effect. In situ IRRAS study showed the oxidation of COH_ads to CO₂. CO_ads was not formed, which is a major breakthrough in methanol electrocatalysis. We synthesized Au Octahedra nanocrystals (NCs) enclosed with Au{111} facets and placed a Pt_ML on them. This catalyst indicates a potential for practical application. Further improvements were achieved using Ru nanoclusters as co-catalyst. In another class of nanocatalysts, core-shell PdAuM (M = Co, Fe, Ni) nanoparticles served as substrates for Pt_ML. Besides enhanced activity, a cost reduction is achieved. Incorporated in DMFC optimized by Shimshon Gottesfeld and his coworkers these catalysts may facilitate a long-awaited application of this power source.