Impact of Organic Cation Adsorption on the Hydrogen Oxidation Reaction of Pt in Alkaline Fuel Cells

Abstract

Relatively poor hydrogen oxidation reaction (HOR) kinetics in alkaline membrane fuel cells compared with those in proton exchange membrane fuel cells can limit the cell performance [1]. In the previous work, we have compared the HOR kinetics of platinum electrocatalysts with two structurally different polymer electrolytes, i.e. benzyl trimethyl ammonium functionalized polyaromatic ionomer and phenyl tetramethyl guanidinium functionalized perfluorinated ionomer [2]. In this presentation, we will give further evidence on organic cation adsorption and their impact on HOR kinetics on Pt under high pH conditions. Direct observation of organic cation adsorption on the disk platinum electrode using surface enhanced FT-IR is closely related to the HOR activities. Computational calculations give further insight on cationic structural effect on adsorption kinetics. Mitigation strategy will be discussed in order to improve HOR kinetics of electrocatalysts in alkaline membrane fuel cells.   Acknowledgements US department of Energy Fuel Cell Technologies Program (Program Manager: Nancy Garland) supports this research through Fuel Cell Incubator Project. References W.C. Sheng, H.A. Gasteiger, Y. Shao-Horn, “Hydrogen Oxidation and Evolution Reaction Kinetics on Platinum: Acid vs Alkaline Electrolytes,” J. Electrochem. Soc., 157, B1529 (2010).Sung-Dae Yim, Hoon T. Chung, Jerzy Chlistunoff, Dae-Sik Kim, Cy Fujimoto, Tae-Hyun Yang, Yu Seung Kim, “A Microelectrode Study of Interfacial Reactions at the Platinum-Alkaline Polymer Interface,” J. Electrochem. Soc., 162, F499 (2015).