Effects of Cell Configurations and Operating Conditions on Cathode Gas‐Phase Products of SO ₂ ‐Depolarized Electrolyzers

The hybrid sulfur (HyS) cycle is a promising process for “green hydrogen” production. As the hydrogen‐producing step of HyS cycle, SO 2 ‐depolarized electrolysis (SDE) has the advantage of very low theoretical cell potential, while crossover of SO 2 and consequent side reactions undermine the purity of hydrogen and the current efficiency. In this study, the cathode gas products are collected and analyzed for SDE cells with different configurations and operated at various conditions. The effects of operating temperature, cell voltage, proton exchange membrane (PEM) thickness, and catalyst loading position on the byproducts and current efficiency are investigated. Optimization of cell configuration and operating parameters has shown promise in enhancing hydrogen purity and current efficiency to higher than 99% and 98%, respectively.