385852 Insights into Hydrogen Oxidation Reaction Mechanisms in Alkaline Electrolytes through the Use of Catalyst with Tunable Oxophilicity

Wednesday, November 19, 2014
Galleria Exhibit Hall (Hilton Atlanta)
Jarrid Wittkopf and Yushan Yan, Chemical & Biomolecular Engineering, University of Delaware, Newark, DE

Hydroxide exchange membrane fuel cells (HEMFC) are an attractive alternative to conventional proton exchange membrane fuel cells (PEMFC) due to the potential of incorporating cost effective materials. The hydrogen oxidation reaction on platinum’s (Pt) surface, which requires a near zero over potential in acidic conditions, turns out to be two orders of magnitude slower in an alkaline environment. Two theories that have been proposed to explain this decreased activity. One focuses on a change in mechanism that involves hydroxide ions in the hydrogen oxidation pathway, while the other suggests it is purely a result of the shift in Pt-hydrogen binding energy in a different chemical environment. The first theory emphasizes the need for proper oxophilicity to allow for increased kinetics. Therefore, by tuning a catalyst’s affinity for oxygen, an enhanced HOR performance should be observed. In this study we present HOR performance on the PtCu catalyst supported on CuNW. By altering the degree of blending of Pt and Cu, different Pt-oxygen affinities can be achieved. However, investigating the effect of the different PtCu catalysts on HOR yielded no significant difference in performance suggesting that the oxophilic nature of the catalyst is of secondary significance.

Extended Abstract: File Not Uploaded