Ren Xiangrong, Zhai Yiyue, Gan Tao, Yang Na, Wang Bolun, Liu Shengzhong Frank
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710119, P. R. China.
School of Civil & Architecture Engineering, Xi'an Technological University, Xi'an, 710021, P. R. China.
Small. 2025 Feb;21(6):e2411017. doi: 10.1002/smll.202411017. Epub 2024 Dec 20.
Mechanistic understanding of how electrode-electrolyte interfaces evolve dynamically is crucial for advancing water-electrolysis technology, especially the restructuring of catalyst surface during complex electrocatalytic reactions. However, for perovskite fluorides, the mechanistic exploration for the influence of the dynamic restructuring on their chemical property and catalytic mechanism is unclear due to their poor conductivity that makes the definition of electrocatalyst structure difficult. Herein, for oxygen evolution reaction (OER), various operando characterizations are employed to investigate the structure-activity relationships of the KNiFe F@NF. Adding iron to the KNiFe F structure increases metal vacancies, enhancing electrochemical reconstruction. For reconstructed KNiFe F structure, the results from operando Raman, operando X-ray diffraction, operando UV-vis spectroscopy, and differential electrochemical mass spectrometry reveal that the surface Ni sites act as catalytic centers within the amorphous Ni(Fe)OOH active layer, and the incorporation of Fe activates oxidized oxygen ions during water oxidation. Theoretical calculations support this by demonstrating the optimized adsorption-free energy of oxygenated intermediates. Consequently, the KNiFeF@NF achieves an overpotential of 281 mV to reach OER current of 150 mA·cm and maintains stable operation for 200 h. These results highlight a promising pathway to tuning OER mechanisms in perovskite fluorides and offer a new perspective for developing high-efficiency and durable OER catalysts.
深入理解电极-电解质界面如何动态演变对于推动水电解技术至关重要，尤其是在复杂的电催化反应过程中催化剂表面的重构。然而，对于钙钛矿氟化物而言，由于其导电性较差，难以确定电催化剂的结构，因此关于动态重构对其化学性质和催化机理影响的机理探索尚不清楚。在此，针对析氧反应（OER），采用了各种原位表征方法来研究KNiFe F@NF的结构-活性关系。在KNiFe F结构中添加铁会增加金属空位，增强电化学重构。对于重构后的KNiFe F结构，原位拉曼光谱、原位X射线衍射、原位紫外-可见光谱和差分电化学质谱的结果表明，表面Ni位点在非晶态Ni(Fe)OOH活性层中充当催化中心，并且Fe的掺入在水氧化过程中激活了氧化的氧离子。理论计算通过证明含氧中间体的优化吸附自由能来支持这一点。因此，KNiFeF@NF在达到150 mA·cm的OER电流时过电位为281 mV，并保持200小时的稳定运行。这些结果突出了一条调节钙钛矿氟化物中OER机理的有前景的途径，并为开发高效耐用的OER催化剂提供了新的视角。
