How to make electrocatalysts more active for direct methanol oxidation - Avoid PtRu bimetallic alloys!

Contrary to the current understanding of Pt-Ru electrocatalyzed oxidation o f methanol, the bimetallic alloy is not the most desired form of the cataly st. In the nanoscale Pt-Ru blacks used to electrooxidize methanol in direct methanol fuel cells, (PtRu0)-Ru-0 has orders of magnitude less activity fo r methanol oxidation than does a mixed-phase electrocatalyst containing Pt metal and hydrous ruthenium oxides (RuOxHy). Bulk, rather than near-surface , quantities of electron-proton conducting RuOxHy are required to achieve h igh activity for methanol oxidation. The active catalyst forms a nanoscopic , phase-separated hydrons oxide-on-metal structure that retains the Pt meta l-RuOxHy boundaries required to oxidize methanol fully to carbon dioxide an d water.