Novel electrocatalysts for direct methanol fuel cells

Methanol-tolerant catalysts were successfully prepared by heat treatment (HT) of a series of single transition metalloporphyrins (V, Mn, Fe, Co, Ni, Cu and Zn) and combination of two transition metalloporphyrins (V/Fe, Co/Fe, Ni/Fe and Cu/Fe). Performance of oxygen reduction in heat-treated metalloporphyrins was evaluated by means of a rotating disk electrode in acid electrolyte with and without methanol. HT-FeTPP/CoTPP is the best catalyst for oxygen reduction, An oxygen reduction mechanism for the heat-treated binary metalloporphyrins is also proposed. The Pt-Ru alloy with an atomic ratio of 50:50 gives the best performance at higher over-potential and high current regions while an atomic ratio of 65:35 shows the best performance at the low over-potential and low current regions. A high surface area of Pt-Ru-Os anode catalyst is synthesized. A single MEA (membrane electrode assembly) methanol fuel cell performance for ARL's Pt-Ru-Os anode shows a very superior performance when compared to a commercial Pt-Ru anode. (C) Published by Elsevier Science B.V.