Single cell study of electrodeposited cathodic electrodes based on Pt–WO3 for polymer electrolyte fuel cells

Cathodic electrodes based on electrodeposited Pt–WO3 material for proton exchange membrane fuel cells (PEMFC) were studied in single cell configuration. Preparation of the electrodes was carried out by electrodeposition of Pt and WO3 on commercial gas diffusion layer substrates (microporous carbon black layer on carbon cloth, ELAT E-TEK). The process of simultaneous electrodeposition of Pt and WO3 is first analyzed from voltammetric curves. It is observed that the deposition of Pt is enhanced when WO3 is present. Compositional analysis of the electrodes shows metallic platinum and WO3 in variable proportions. The electrodeposited electrodes were characterized in single PEMFC. Membrane–electrode assemblies were prepared with Nafion® 117 electrolyte membrane and a standard Pt/C anode. Pt–WO3 electrodes showed enhanced stability and good response in single cell up to 1500 h. Performance degradation is attributed to a decrease in Pt electroactive area and increase of the internal resistance of the cell. These effects are possibly a consequence of the production of mobile tungsten species, like soluble WO2 at high current demands and low cathode potentials.