Out-of-plane coordination of iridium single atoms with organic molecules and cobalt–iron hydroxides to boost oxygen evolution reaction

• Published in: Nature nanotechnology Vol. 20; no. 1; pp. 57 - 66
• Main Authors: Zhao, Jie, Guo, Yue, Zhang, Zhiqi, Zhang, Xilin, Ji, Qianqian, Zhang, Hua, Song, Zhaoqi, Liu, Dongqing, Zeng, Jianrong, Chuang, Chenghao, Zhang, Erhuan, Wang, Yuhao, Hu, Guangzhi, Mushtaq, Muhammad Asim, Raza, Waseem, Cai, Xingke, Ciucci, Francesco
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2025; Nature Publishing Group
• Subjects: 119/118; 140/133; 140/146; 639/301/299/886; 639/301/357/1018; 639/638/161/886; 639/638/77/886; 639/925/357/1018; Atomic properties; Catalysts; Chemistry and Materials Science; Cobalt; Coordination; Current density; Evolution; Ferrous hydroxide; Hydroxides; Iridium; Iron; Ligands; Materials Science; Microscopy; Nanoparticles; Nanotechnology; Nanotechnology and Microengineering; Noble metals; Organic chemistry; Oxidation; Oxygen; Oxygen evolution reactions; Precious metals
• ISSN: 1748-3387; 1748-3395; 1748-3395
• DOI: 10.1038/s41565-024-01807-x

Advancements in single-atom-based catalysts are crucial for enhancing oxygen evolution reaction (OER) performance while reducing precious metal usage. A comprehensive understanding of underlying mechanisms will expedite this progress further. Here we report Ir single atoms coordinated out-of-plane with dimethylimidazole (MI) on CoFe hydroxide (Ir 1 /(Co,Fe)-OH/MI). This Ir 1 /(Co,Fe)-OH/MI catalyst, which was prepared using a simple immersion method, delivers ultralow overpotentials of 179 mV at a current density of 10 mA cm −2 and 257 mV at 600 mA cm −2 as well as an ultra-small Tafel slope of 24 mV dec −1 . Furthermore, Ir 1 /(Co,Fe)-OH/MI has a total mass activity exceeding that of commercial IrO 2 by a factor of 58.4. Ab initio simulations indicate that the coordination of MI leads to electron redistribution around the Ir sites. This causes a positive shift in the d -band centre at adjacent Ir and Co sites, facilitating an optimal energy pathway for OER. This article presents a new method for coordinating iridium atoms with dimethylimidazole and cobalt–iron hydroxides. This enhances the oxygen evolution reaction and delivers high current densities with reduced precious metal use.