TiO2 Supported Au Catalysts for Selective Catalytic Oxidation of CO to CO2 in Fuel Cell Operating Conditions

摘要

Methods for the removal of CO from hydrogen-rich fuel still needs to be resolved in the drive towards commercialisation of proton exchange membrane (PEM) fuel cells.Whether present as percentage levels in on-board reformed fuels,or as 10 ppm in purified hydrogen,CO adsorbs onto the Pt electrocatalyst at the anode and prevents the anodic oxidation of gaseous hydrogen to hydrogen ions.The need therefore exists to develop CO tolerant anodes,or to remove CO from the hydrogen fuel to concentrations lower than 1 ppm.In this study,a TiO2 supported Au catalyst has been developed for the catalytic oxidation of CO to CO2 under conditions similar to that found in PEM fuel cells.Two possible systems,namely CO tolerance and CO cleanup/removal,were investigated.In the former,a Au/TiO2 catalyst was incorporated into the membrane electrode assembly (MEA) in a bi-layer configuration,whereas CO cleanup/removal was investigated by incorporating an isolated Au/TiO2 catalyst chamber prior to the fuel cell.In each case a 2 per cent air bleed stream was introduced with the hydrogen fuel to facilitate CO oxidation.The efficiencies of these systems were compared to that of PtRu anodes,which are known to have higher CO tolerance than normal Pt anodes.