Some Recent Studies in Ruthenium Electrochemistry and Electrocatalysis

Abstract

Ruthenium is a metal of a considerable importance in electrochemical science and technology. It is a catalyst or co-catalyst material in Pt-Ru alloys for methanol- and reformate hydrogenoxidation in fuel cells, while ruthenium oxide, a component in chlorine-evolution catalysts, represents an attractive material for electrochemical supercapacitors. Its facile surface oxidation generates an oxygen-containing species that provides active oxygen in some reactions. Ru sites in Pt-Ru catalysts increase the “CO tolerance” of Pt in the catalytic oxidation-reaction in direct methanol fuel cells (DMFC) and in reformate hydrogen-oxidation in proton exchange membrane fuel cells (PEMFC). The mechanism of Ru action is not completely understood, although the current consensus revolves around the so-called “bifunctional mechanism” wherein Ru provides oxygenated species to oxidize CO that blocks Pt sites, and has an electronic effect on Pt-CO interaction.