The Effects of Operating Conditions on the Electrode-Specific Potentials and Overall Performance of a Polymer Exchange Membrane Water Electrolyzer

Abstract

Proton exchange member water electrolysis (PEMWE) is a crucial technology for the future of clean, sustainable energy systems. However, PEMWE cells use iridium metal as the anode catalyst, which is scarce and prone to high prices and price volatility. To address this problem, researchers have investigated different methods to increase catalyst utilization, thereby reducing catalyst loading and increasing overall MEA durability. One of the governing factors of the durability of both the cathode and anode catalyst is the redox state of the metal catalyst since Pt-dissolution occurs between ~0.9 and 1 V in the acidic conditions of the cell, and IrO2 reduces to Irmetal at potentials below ~1 V which is less stable than the oxide [1]. Past research has found that hydrogen crossover is one of the leading contributors to IrOx reduction since the overall cell potential goes to 0 V when held idle for a while [2]. This study used a custom-made hydrogen reference electrode to deconvolve the electrode-specific potentials under various operating conditions. It was found that anode catalyst loading, feedwater dissolved gas concentration, and cell voltage affect the electrode-specific potentials and the overall cell performance.[1] S. Song et al. 2008 Int J of Hydrogen Energy 2008;33:4955–61[2] P. J. Rheinländer and J. Durst 2021 J. Electrochem. Soc. 168 024511