Gold as an efficient hydrogen isotope separation catalyst in proton exchange membrane water electrolysis. (26th July 2022)

• Record Type: Journal Article
• Authors: Xue, Xiaochong; Zhang, Mingjun; Wei, Fei; Liang, Chaofei; Liang, Jie; Li, Jinglin; Cheng, Wenyu; Deng, Ke; Liu, Wei
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 63(2022)
• Page Start: 26842
• Page End: 26849
• Publication Date: 2022-07-26
• Subjects: Hydrogen isotope separation -- PEM water electrolysis -- Hydrogen evolution reaction -- Kinetic isotope effect -- Gold catalyst; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.06.052
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The development of proton exchange membrane water electrolysis (PEMWE) offers an updating potential for electrolytic hydrogen isotope separation. However, it has a significantly lower separation factor than the traditional alkaline water electrolysis. In this study, we propose gold as a promising cathodic catalyst for efficient hydrogen isotope separation in PEMWE. Au/C has a protium-to-deuterium (H/D) separation factor of 7.47 in PEMWE, about twice that of Pt/C. In addition, the full cell's electrochemical performance is comparable to that of its Pt/C counterpart. The separation mechanism in PEMWE is explained by the transitional hydrogen evolution reaction mechanism from Heyrovsky to Tafel for Pt and the unchangeable Volmer mechanism for Au. The high separation factor for Au is also calculated by the H/D zero-point vibrational energy difference between transition state and reaction state through a simple density functional theory calculation. This work offers an effective strategy to improve hydrogen isotope separation efficiency in PEMWE. Graphical abstract: Au/C has a high hydrogen isotope separation factor of 7.5 in the PEMWE cell through the Volmer mechanism, about twice that of Pt/C which follows the Tafel mechanism. Image 1 Highlights: The electrolytic hydrogen isotope separation factor of Au/C was nearly twice that of Pt/C. Au/C was employed as a cathodic catalyst in a PEM water electrolyzer for the first time. The hydrogen isotope separation mechanism for Pt was elucidated by the HER mechanism transition. The high separation factor for Au was confirmed by the ZPE difference between H and D.