Nafion–Imidazole– H3PO4 Composite Membranes for Proton Exchange Membrane Fuel Cells

Abstract

Water in Nafion 115 membranes was replaced by imidazole and then doped with to form imidazole– complexes as proton solvent. Both the Nafion–imidazole and Nafion–imidazole– composite membranes exhibited higher proton conductivity than the plain Nafion membrane under anhydrous conditions at . Although the Nafion–imidazole membranes with Pt catalyst exhibit poor performance in proton exchange membrane fuel cells (PEMFCs) at low temperatures (60 and ) due to the poisoning of the Pt catalyst by imidazole, doping with improves the fuel cell performance significantly due to the suppression of imidazole poisoning through the formation of imidazolium salt with . The imidazole poisoning could also be suppressed further by replacing the Pt catalyst with a newly developed Pd–Co–Mo catalyst. The Nafion–imidazole– membranes with the Pd–Co–Mo catalyst show performance superior to that of Nafion membrane with the Pt or Pd–Co–Mo catalyst in PEMFCs at .