Huang Guangxing, Yuan Tenghui, Li Bing, Peng Chaoxia, Wang Liuchen, Wang Limei, Xiong Xunhui, Liu Enzuo, Wang Wei, Zhao Bote
School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China.
School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350, People's Republic of China.
Nano Lett. 2025 Apr 9;25(14):5803-5811. doi: 10.1021/acs.nanolett.5c00462. Epub 2025 Mar 27.
Electrolyte modulation can enhance the performance of electrocatalysts for the oxygen evolution reaction (OER) by tailoring the electrocatalyst-electrolyte interface, but the role of anion additives remains controversial. Herein, we report our findings on unraveling the effects of oxyanions (NO, SO, and PO) and identifying Fe impurities as the key factor driving OER activity enhancement in Ni hydr(oxy)oxide model catalysts. Fe impurities, introduced via oxyanion salts, significantly enhance OER activity, while oxyanions themselves have minimal direct impact when Fe ions are removed. Our results, including Raman spectroscopy, reveal that Fe enhances Ni reducibility/redox reversibility. X-ray absorption spectroscopy and density functional theory calculations indicate that Fe preferentially adsorbs on Ni surface sites with higher deprotonation energy. These findings reveal the critical role of surface-adsorbed Fe in modulating Ni hydr(oxy)oxide activity and highlight overlooked impurity effects in electrocatalysis when studying additive effects in electrolyte modulation.
电解质调制可通过调整电催化剂 - 电解质界面来提高析氧反应（OER）电催化剂的性能，但阴离子添加剂的作用仍存在争议。在此，我们报告了关于揭示含氧阴离子（NO、SO和PO）的影响以及确定铁杂质是驱动氢氧化镍模型催化剂中OER活性增强的关键因素的研究结果。通过含氧阴离子盐引入的铁杂质显著提高了OER活性，而当去除铁离子时，含氧阴离子本身的直接影响极小。我们的结果，包括拉曼光谱，表明铁增强了镍的还原性/氧化还原可逆性。X射线吸收光谱和密度泛函理论计算表明，铁优先吸附在去质子化能量较高的镍表面位点上。这些发现揭示了表面吸附的铁在调节氢氧化镍活性中的关键作用，并突出了在研究电解质调制中的添加剂效应时电催化中被忽视的杂质效应。
