Abstract: Use of a proton exchange membrane M in proton exchange membrane fuel cells, wherein the membrane M comprises a blend of (I) at least one polybenzimidazole polymer PBI which comprises, in polymerized form, at least 90 mol-% monomeric units U of formula (I) and/or (II), based on the total amount of monomeric units of the polybenzimidazole polymer PBI, wherein Y is a substituted element selected from O and S; or Y is a single carbon-carbon bond; Z is selected from the group consisting of divalent C1-C10 alkanediyl; divalent C2-C10 alkenediyl; divalent C6-C15 aryl; divalent C5-C15 heteroaryl; divalent C5-C15 heterocyclyl; divalent C6-C19 aryl sulfone; and divalent C6-C19 aryl ether; and wherein the total amount of monomeric units U in the polybenzimidazole polymer PBI is from about 100 to about 10,000; and (III) at least one sulfonated polymer SP, which comprises, in polymerized form, at least 50 mol-% monomeric units U?, based on the total amount of monomeric units of the sulfonated polymer SP, wherein at least

Abstract: Provided is a fuel cell having a selective CO oxidation catalyst with an electronically conductive, particulate support dispersed on a gas diffusion membrane, and a membrane electrode assembly. Also provided is a method of supplying a purified reformate gas to a membrane electrode assembly. The method includes contacting a reformate gas comprising H2 and CO with a gas diffusion membrane while simultaneously adding an oxidant to the reformate gas to convert at least some of the CO to CO2 to form the purified reformate gas. Dispersed on the gas diffusion membrane is a selective CO oxidation catalyst with an electronically conductive, particulate support. The purified reformate gas is then passed to the membrane electrode assembly.