中国科学技术大学曾杰团队近日取得一项新成果。经过不懈努力，他们研究出单粒子水平空间分辨成像揭示了铁掺杂氢氧化镍中位置特异性铁对水氧化的作用。相关论文于2025年4月2日发表在《美国化学会杂志》上。

在此，该研究团队确定了单晶NiFe基氢氧化物上的边缘位点对OER主题空间分辨原位单粒子成像技术的关键作用。在二维（2D） Ni层双氢氧化物（LDH）单晶上实现了铁在特定边缘或平面位置的电位驱动结合。空间分辨扫描电化学细胞显微镜成像表明，Fe掺杂的边缘位点而不是Fe掺杂的平面位点主导了OER的活性。单粒子的原位拉曼光谱成像以监测边缘和面位的演变为主题，揭示了Fe的加入阻碍了Ni的氧化。

此外，空间分辨的¹⁸O-同位素标记实验表明，Fe掺杂阻碍了Ni LDH与电解质之间的氧交换，导致部分活性位点从Ni切换到Fe。结合理论计算，Fe - O_bridge - Ni位点有助于Ni LDH边缘掺杂Fe的OER活性增强，而Fe渗入平面诱导的O_hollow （NiNiFe）位点则不利于OER性能。这项工作为在单粒子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。

据悉，可再生电力驱动的水电解受到慢动力学析氧反应（OER）的限制。NiFe基氢氧化物被认为是很有前途的非贵金属OER电催化剂，但需要深入了解特定位点铁结合的作用。

附：英文原文

Title: Role of Site-Specific Iron in Fe-Doped Nickel Hydroxide Toward Water Oxidation Revealed by Spatially Resolved Imaging at the Single-Particle Level

Author: Jie Wei, Jing Zhu, Rong Jin, Yan Liu, Guiliang Liu, Ming-Hui Fan, Mingkai Liu, Dechen Jiang, Jie Zeng

Issue&Volume: April 2, 2025

Abstract: 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 18O-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–Obridge–Ni sites contributed to the enhanced OER activity on Ni LDH with Fe doping at the edge, whereas the Ohollow (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.

DOI: 10.1021/jacs.5c00438

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c00438