Proton exchange membrane (PEM) water electrolysis represents a feasible technology for ‘green’ hydrogen production. However, the efficiency of the electrolyzers can be compromised by foreign ions in the feed water. In particular, sodium ions (Na), which are commonly found in water sources, poses a serious threat for the operation of PEM water electrolyzers. This work examines the effects of low-concentration Na on the performance of membrane electrode assemblies (MEAs). Results reveal that Na can diminish the H concentration () and cation diffusion coefficient () in the isomer and PEM by substituting H sites, but doesn’t cause irreversible catalyst or structure damage. The reduced can lead to a negative shift in equilibrium potential, particularly at the cathode. Concurrently, a lowered slows down the movement of cations, which serve as reactants at the cathode, resulting in impeded mass transport. Additionally, the work presents a methodology for recovering the performance of Na poisoned MEAs. Operating the electrolyzer at high current densities, 6.0 A cm, could aid in the re-equilibration of Na/H and the expulsion of Na from the MEAs. With Pt-coated Ti porous transport layers employed, the poisoned MEAs can be recovered to their original performance levels. This work presents an effective countermeasure to manage the Na poisoning in PEM electrolyzers and overcome this prohibitive barrier to the commercial viability of this technology.

中文翻译：

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质子交换膜水电解中Na离子对膜电极组件的中毒效应及恢复策略

质子交换膜（PEM）水电解代表了一种“绿色”制氢的可行技术。然而，电解槽的效率可能会因给水中的异物离子而受到影响。特别是水源中常见的钠离子（Na）对质子交换膜水电解槽的运行构成严重威胁。这项工作研究了低浓度 Na 对膜电极组件 (MEA) 性能的影响。结果表明，Na可以通过取代H位来降低异构体和PEM中的H浓度（）和阳离子扩散系数（），但不会造成不可逆的催化剂或结构损伤。还原会导致平衡电位的负移，特别是在阴极。同时，降低会减慢作为阴极反应物的阳离子的运动，导致质量传输受阻。此外，该工作还提出了一种恢复钠中毒 MEA 性能的方法。在高电流密度（6.0 A cm）下操作电解槽有助于 Na/H 的重新平衡以及 Na 从 MEA 中的排出。通过采用 Pt 涂层的 Ti 多孔传输层，中毒的 MEA 可以恢复到其原始性能水平。这项工作提出了一种有效的对策来管理 PEM 电解槽中的钠中毒，并克服该技术商业可行性的这一障碍。