Microenvironment reconstitution of highly active Ni single atoms on oxygen-incorporated Mo2C for water splitting

• Published in: Nature communications Vol. 15; no. 1; pp. 1342 - 13
• Main Authors: Hou, Mengyun, Zheng, Lirong, Zhao, Di, Tan, Xin, Feng, Wuyi, Fu, Jiantao, Wei, Tianxin, Cao, Minhua, Zhang, Jiatao, Chen, Chen
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.02.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 140/146; 147/143; 147/28; 639/4077/909; 639/638/77; Absorption spectroscopy; Adsorption; Coordination numbers; Dispersion; Electrocatalysts; Electrolysis; Electron microscopy; Humanities and Social Sciences; Hydrogen evolution reactions; Industrial water; Metal oxides; Microenvironments; Microscopy; Molybdenum; multidisciplinary; Nickel; Oxidation; Oxygen; Oxygen evolution reactions; Science; Science (multidisciplinary); Splitting; Synchrotron radiation; Water splitting; X ray absorption; X-ray absorption spectroscopy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-45533-3

The rational design of efficient bifunctional single-atom electrocatalysts for industrial water splitting and the comprehensive understanding of its complex catalytic mechanisms remain challenging. Here, we report a Ni single atoms supported on oxygen-incorporated Mo 2 C via Ni-O-Mo bridge bonds, that gives high oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) bifunctional activity. By ex situ synchrotron X-ray absorption spectroscopy and electron microscopy, we found that after HER, the coordination number and bond lengths of Ni-O and Ni-Mo (Ni-O-Mo) were all altered, yet the Ni species still remain atomically dispersed. In contrast, after OER, the atomically dispersed Ni were agglomerated into very small clusters with new Ni-Ni (Ni-O-Ni) bonds appeared. Combining experimental results and DFT calculations, we infer the oxidation degree of Mo 2 C and the configuration of single-atom Ni are both vital for HER or OER. This study provides both a feasible strategy and model to rational design highly efficient electrocatalysts for water electrolysis. The comprehensive understanding of complex catalytic mechanisms under harsh reaction conditions for efficient bifunctional single-atom electrocatalysts remain challenging. Here the authors found microenvironment reconsitution of highly active Ni single atoms on oxygen-incorporated Mo2C for water splitting.