Activity and Stability of Molybdenum-Containing Dispersed Pt Catalysts for CO Tolerance in Proton Exchange Membrane Fuel Cell Anodes

摘要

In this work, results of attempts to improve the activity and stability of Mo-containing dispersed Pt catalysts for the CO tolerance in proton exchange membrane fuel cell (PEMFC) anodes are revised for the following approaches: (1) application of a heat treatment at various temperatures ranging from 400 to 700°C on carbon supported PtMo (60:40, Pt:Mo) electrocatalyst; (2) deposition of Pt and PtMo nanoparticles on carbon-supported molybdenum carbides (Mo_2C/C) and; (3) employing ternary and quaternary materials formed by PtMoFe/C, PtMoRu/C and PtMoRuFe/C. The Pt-Mo/C catalyst heat-treated at 600°C showed higher hydrogen oxidation activity in the absence and in the presence of CO and better stability, compared to all other Mo-containing catalysts. Similar CO tolerances were observed for PtMoRuFe, PtMoFe, PtMoRu supported on carbon, and for Pt supported on Mo_2C/C, which also presented better stability, as compared to as-prepared PtMo supported on carbon. However, partial dissolution of Mo, Ru, and Fe from the anodes and their migration toward cathodes during the cell operation was observed.