Wei Jie, Zhu Jing, Jin Rong, Liu Yan, Liu Guiliang, Fan Ming-Hui, Liu Mingkai, Jiang Dechen, Zeng Jie
Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
The State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210093, P. R. China.
J Am Chem Soc. 2025 Apr 23;147(16):13502-13511. doi: 10.1021/jacs.5c00438. Epub 2025 Apr 2.
Water electrolysis driven by renewable electricity is limited by the slow-kinetic oxygen evolution reaction (OER). NiFe-based hydroxides are considered promising non-noble electrocatalysts toward the OER but require profound insight into the role of site-specific iron incorporation. Herein, we determined the critical role of edge sites on single-crystalline NiFe-based hydroxide toward the OER using spatially resolved in situ single-particle imaging techniques. The potential-driven incorporation of Fe into the specific edge or plane sites was achieved on two-dimensional (2D) Ni layer double hydroxide (LDH) single crystals. The spatially resolved scanning electrochemical cell microscopy imaging illustrated that Fe-doped edge sites dominated the activity of the OER rather than Fe-doped plane sites. In situ Raman spectroscopy imaging of single particles was used to monitor the evolution of edge and plane sites, revealing that the incorporation of Fe impeded the oxidation of Ni. Moreover, spatially resolved O-isotope-labeling experiments demonstrated that Fe doping hindered the oxygen exchange between Ni LDH and the electrolyte, inducing the switch of partial active sites from Ni to Fe. Combined with theoretical calculations, the Fe-O-Ni sites contributed to the enhanced OER activity on Ni LDH with Fe doping at the edge, whereas the O (NiNiFe) sites induced by the infiltration of Fe into the plane were detrimental to the OER performance. This work provides direct spectroscopic evidence for understanding the specific sites at the single-particle level and guides the rational design of optimal electrocatalysts.
由可再生电力驱动的水电解受到动力学缓慢的析氧反应（OER）的限制。镍铁基氢氧化物被认为是有前景的OER非贵金属电催化剂，但需要深入了解特定位置铁掺入的作用。在此，我们使用空间分辨原位单颗粒成像技术确定了单晶镍铁基氢氧化物上边缘位点对OER的关键作用。在二维（2D）镍层双氢氧化物（LDH）单晶上实现了铁在特定边缘或平面位点的电位驱动掺入。空间分辨扫描电化学池显微镜成像表明，铁掺杂的边缘位点主导了OER的活性，而不是铁掺杂的平面位点。单颗粒的原位拉曼光谱成像用于监测边缘和平面位点的演变，揭示铁的掺入阻碍了镍的氧化。此外，空间分辨的氧同位素标记实验表明，铁掺杂阻碍了镍LDH与电解质之间的氧交换，导致部分活性位点从镍切换到铁。结合理论计算，铁 - 氧 - 镍位点有助于提高边缘掺杂铁的镍LDH上的OER活性，而铁渗入平面诱导的O（NiNiFe）位点对OER性能不利。这项工作为在单颗粒水平上理解特定位点提供了直接的光谱证据，并指导了最佳电催化剂的合理设计。
