Wang Zekun, Wang Chao, Ye Lin, Liu Xien, Xin Liantao, Yang Yuanyuan, Wang Lei, Hou Wanguo, Wen Yonghong, Zhan Tianrong
Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science (Ministry of Education), College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
Key Laboratory of Colloid & Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100, China.
Inorg Chem. 2022 Sep 26;61(38):15256-15265. doi: 10.1021/acs.inorgchem.2c02579. Epub 2022 Sep 9.
Compared to freshwater electrolysis, seawater electrolysis to produce hydrogen is preferable and more promising, but this technology is plagued by the electrode's corrosion and oxidative reactions of the competitive Cl ion on the anode. To develop efficient oxygen evolution reaction (OER) catalysts for seawater electrolysis, the ultrathin MnO film-covered NiFe-layered double-hydroxide nanosheet array is directly assembled on Ni foam (MnO/NiFe-LDH/NF) by hydrothermal and electrodeposition in turn. This catalyst demonstrates excellent OER-selective activity in alkaline saline electrolytes. In 1 M KOH/0.5 M NaCl and 1 M KOH/seawater electrolytes, MnO/NiFe-LDH/NF exhibits lower overpotentials at 100 mA cm (η values of 265 and 276 mV, respectively) and Tafel slopes (73 and 77 mV decade, respectively) than does the NiFe-LDH/NF electrode (η values of 298 and 327 mV and Tafel slopes of 91 and 140 mV decade, respectively). In alkaline saline solutions, the stability and durability of the former are also better than those of the latter. The good OER selectivity and catalytic performance are attributed to the MnO overlayer that selectively blocks Cl anions from approaching catalytic centers, and the good conductivity, fast kinetics, more oxygen vacancies, and abundant active sites of MnO/NiFe-LDH/NF. The robust stability is due to the enhanced resistance for Cl corrosion stemming from the MnO protective film. Hence, MnO/NiFe-LDH/NF can act as a promising OER electrocatalyst for alkalized natural seawater electrolysis.
与淡水电解相比，海水电解制氢更具优势且前景广阔，但该技术受电极腐蚀以及阳极上竞争性Cl离子的氧化反应困扰。为开发用于海水电解的高效析氧反应（OER）催化剂，通过水热法和电沉积依次将超薄MnO膜覆盖的NiFe层状双氢氧化物纳米片阵列直接组装在泡沫镍上（MnO/NiFe-LDH/NF）。该催化剂在碱性盐电解质中表现出优异的OER选择性活性。在1 M KOH/0.5 M NaCl和1 M KOH/海水电解质中，MnO/NiFe-LDH/NF在100 mA cm时的过电位较低（η值分别为265和276 mV），塔菲尔斜率（分别为73和77 mV dec⁻¹），低于NiFe-LDH/NF电极（η值分别为298和327 mV，塔菲尔斜率分别为91和140 mV dec⁻¹）。在碱性盐溶液中，前者的稳定性和耐久性也优于后者。良好的OER选择性和催化性能归因于MnO覆盖层选择性地阻止Cl阴离子接近催化中心，以及MnO/NiFe-LDH/NF良好的导电性、快速的动力学、更多的氧空位和丰富的活性位点。强大的稳定性归因于MnO保护膜增强了对Cl腐蚀的抗性。因此，MnO/NiFe-LDH/NF可作为用于碱化天然海水电解的有前景的OER电催化剂。
