DIRECT ANODIC-OXIDATION OF METHANOL ON SUPPORTED PLATINUM RUTHENIUM CATALYST IN AQUEOUS CESIUM CARBONATE

Methanol electro-oxidation was carried out on porous gas diffusion electrodes in Cs2CO3 electrolytes at 100 to 140 degrees C and ambient pressures. It was found that Pt-Ru bimetallic catalysts supported on graphitized carbon provided enhanced performance, compared to supported Pt catalyst. Performance curves, based on unit catalyst mass, for Pt-Ru at 120 degrees C matched or exceeded previously reported performance data for supported Pt or Pt black in concentrated Cs2CO3 electrolytes at 120 to 150 degrees C at 8 atm, and for supported Pt-Ru in concentrated H3PO4 electrolytes at 200 degrees C. It was found that the polytetrafluoroethylene (PTFE) content in the reaction layer, and consequently the extent of wetting, had a marked effect on cell performance, and 20 to 30 weight percent PTFE was found to be optimal. Maximum cell performance was found at operating temperatures 10 to 15 degrees C below the boiling pint of the electrolyte.