Towards Thin Membrane Use in Polymer Electrolyte Water Electrolysis Using Pt Recombination Catalyst

Abstract

A key concern for the safe operation of polymer electrolyte water electrolysis (PEWE) cells is the high hydrogen gas crossover that could lead to explosive hydrogen-oxygen gas mixtures (1). The safety aspect is especially important with thin membranes and high differential pressures. So far, different approaches have been taken to suppress the hydrogen gas crossover or to reduce the content of hydrogen in the anode compartment. The concept of Pt doping of the proton exchange membrane (PEM) by Pt-salt impregnation followed by chemical reduction is well known from polymer electrolyte fuel cells (PEFCs), where it was used for electrode preparation and self-humidification. The Pt particles in such impregnated membranes serve as recombination catalyst and can be applied to reduce hydrogen crossover in PEWE. In this study, we present a new reduction method yielding thin membranes with high crossover suppression as well as good performance for an increase of the operational range of the PEWE cell (Figure 1) (2).(1) U. Babic, M. Suermann, F. N. Büchi, L. Gubler and T. J. Schmidt, Journal of The Electrochemical Society, 164, F387 (2017).(2) S. Garbe, U. Babic, E. Nilsson, T. J. Schmidt and L. Gubler, Journal of The Electrochemical Society, 166, F873 (2019). Figure 1