Monitoring Hydrogen Crossover Through Commercial Separators via a Facile In Situ Electrochemical Detection Method

Hydrogen crossover, the undesired diffusion of hydrogen from the cathode to the anode in a water electrolyzer, is a critical issue in these devices since it lowers efficiency and poses safety risks. Thus, monitoring hydrogen crossover in real time is highly important. However, existing hydrogen detection methods often rely on complex and/or expensive instrumentation, and are poorly suited for fast screening. Here, a fast and accessible electrochemical method was developed for comparative screening of hydrogen crossover in lab‐scale electrolysis cells under ambient conditions. The detection setup employs a four‐electrode cell configuration, enabling hydrogen production and detection to occur in separate chambers across a test separator. By combining cyclic voltammetry and chronoamperometry, this method allows for relative evaluation of separator performance without the need for complex or costly instrumentation. A set of commercial separators was tested in alkaline electrolytes and a brewery waste‐like salt solution. Results demonstrated that the method could consistently differentiate separators based on their hydrogen crossover performance. This technique enables rapid identification of separators with favorable gas‐blocking characteristics and can potentially be optimized and applied to monitor other compounds, thus offering a practical screening tool for separator selection in various electrochemical applications.