Demnitz Maximilian, Lamas Yuran Martins, Garcia Barros Rodrigo Lira, de Leeuw den Bouter Anouk, van der Schaaf John, Theodorus de Groot Matheus
Department of Chemical Engineering and Chemistry, Sustainable Process Engineering Group, Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600 MB, the Netherlands.
Eindhoven Institute for Renewable Energy Systems, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, the Netherlands.
iScience. 2023 Dec 10;27(1):108695. doi: 10.1016/j.isci.2023.108695. eCollection 2024 Jan 19.
Improvement of alkaline water electrolysis is a key enabler for quickly scaling up green hydrogen production. Fe is omnipresent within most industrial alkaline water electrolyzers and its effect on electrolyzer performance needs to be assessed. We conducted three-electrode and flow cell experiments with electrolyte Fe and Ni electrodes. Three-electrode cell experiments show that Fe ([Fe] = 6-357 μM; ICP-OES) promotes HER and OER by lowering both overpotentials by at least 100 mV at high current densities (T = 35°C-91°C). The overpotential of a zero-gap flow cell was decreased by 200 mV when increasing the Fe concentration ([Fe] = 13-549 μM, T = 21°C-75°C). HER benefits from the formation of Fe dendrite layers (SEM/EDX, XPS), which prevent NiH formation and increase the overall active area. The OER benefits from the formation of mixed Ni/Fe oxyhydroxides leading to better catalytic activity and Tafel slope reduction.
碱性水电解的改进是快速扩大绿色氢生产规模的关键推动因素。铁在大多数工业碱性水电解槽中普遍存在，需要评估其对电解槽性能的影响。我们使用含电解质铁和镍电极进行了三电极和流通池实验。三电极电池实验表明，铁（[Fe]=6-357μM；电感耦合等离子体发射光谱法）通过在高电流密度下（温度=35°C-91°C）将过电位至少降低100mV来促进析氢反应（HER）和析氧反应（OER）。当增加铁浓度时（[Fe]=13-549μM，温度=21°C-75°C），零间隙流通池的过电位降低了200mV。析氢反应受益于铁枝晶层的形成（扫描电子显微镜/能谱仪、X射线光电子能谱），该层可防止氢化镍的形成并增加整体活性面积。析氧反应受益于混合镍/铁羟基氧化物的形成，从而导致更好的催化活性和塔菲尔斜率降低。
