Importance of hydrogen oxidation reaction current in quantifying hydrogen crossover in PEM water electrolyzers at high differential pressure

• Published in: Energy & environmental science Vol. 18; no. 1; pp. 4625 - 4631
• Main Authors: Gawas, Ramchandra, Kushner, Douglas I, Peng, Xiong, Mukundan, Rangachary
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 20.05.2025
• Subjects: Chromatography; Crossovers; Differential pressure; Gas chromatography; Hydrogen; Hydrogen permeation; Oxidation
• ISSN: 1754-5692; 1754-5706
• DOI: 10.1039/d5ee00048c

Understanding hydrogen permeation in proton exchange membrane water electrolyzers (PEMWEs) operating at high differential pressures (>25 bar) is critical towards developing effective gas recombination strategies that enable safe operation and high efficiency. Developing this understanding relies on accurate quantification of hydrogen crossover rates in water electrolyzers operating under such conditions. In this work, we show that PEMWEs operating at high differential pressures exhibit noticeable hydrogen oxidation reaction (HOR) currents. As the HOR consumes part of the permeated hydrogen at the anode, neglecting HOR currents leads to severe underestimation of the hydrogen crossover rate. We implemented a new method combining hydrogen oxidation current with online gas chromatography measurements to accurately quantify hydrogen crossover rates as a function of operating current density in PEMWEs operating at high differential pressures (10-30 bar g ). This work employs online gas chromatography and hydrogen oxidation current measurements for accurate quantification of the hydrogen crossover rates in proton exchange membrane water electrolyzers operating at high differential pressure.