Xue Xiaochong, Chu XinXin, Zhang Mingjun, Wei Fei, Liang Chaofei, Liang Jie, Li Jinglin, Cheng Wenyu, Deng Ke, Liu Wei
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Appl Mater Interfaces. 2022 Jul 20;14(28):32360-32368. doi: 10.1021/acsami.2c06394. Epub 2022 Jul 6.
Single-layer graphene has been demonstrated to be a high-efficiency hydrogen isotope sieving membrane in the electrochemical hydrogen pumping system. In this work, we transferred this membrane to proton exchange membrane water electrolysis (PEMWE), which has wide industrial applications. Two membrane electrode assemblies with decorated Pt and ink-coated Pt were investigated. The graphene with the decorated Pt scheme acquired the reported highest proton-to-tritium separation factor of 19.50 in PEMWE. However, rather than graphene, the decorated catalyst was demonstrated to be responsible for this remarkable separation efficiency. Previous studies from Geim's group underestimated the enhanced separation efficiency of decorated Pt over ink-coated Pt, resulting in an exaggerated separation efficiency for graphene. The behavior of proton transfer with hydrogen isotope separation through graphene was interpreted by a serial-parallel circuit model, which suggested that hydrogen isotope separation occurs at defect sites. The limited separation efficiency for graphene was also well understood by a density functional theory (DFT) calculation using an SW 55-77 model and the transition state theory for the kinetic isotope effect. This research provides a thorough understanding of proton transfer with hydrogen isotope separation through graphene.
单层石墨烯已被证明是电化学氢泵系统中的一种高效氢同位素筛分膜。在这项工作中，我们将这种膜应用于具有广泛工业应用的质子交换膜水电解（PEMWE）。研究了两种分别带有修饰铂和油墨涂覆铂的膜电极组件。采用修饰铂方案的石墨烯在PEMWE中获得了已报道的最高质子与氚分离因子19.50。然而，经证明，造成这种显著分离效率的原因并非石墨烯，而是修饰后的催化剂。盖姆团队之前的研究低估了修饰铂相对于油墨涂覆铂的增强分离效率，从而夸大了石墨烯的分离效率。通过串并联电路模型解释了质子通过石墨烯进行氢同位素分离时的转移行为，该模型表明氢同位素分离发生在缺陷位点。利用SW 55 - 77模型的密度泛函理论（DFT）计算以及动力学同位素效应的过渡态理论，也很好地理解了石墨烯有限的分离效率。这项研究全面深入地理解了质子通过石墨烯进行氢同位素分离时的转移情况。
