Understanding the sulphur-oxygen exchange process of metal sulphides prior to oxygen evolution reaction

• Published in: Nature communications Vol. 14; no. 1; p. 1949
• Main Authors: Hu, Yang, Zheng, Yao, Jin, Jing, Wang, Yantao, Peng, Yong, Yin, Jie, Shen, Wei, Hou, Yichao, Zhu, Liu, An, Li, Lu, Min, Xi, Pinxian, Yan, Chun-Hua
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 07-04-2023; Nature Publishing Group; Nature Portfolio
• Subjects: 147/28; 639/638/77/886; 639/925/357/537; Bimetals; Catalysts; Cobalt; Electrochemistry; Electron energy loss spectroscopy; Energy loss; Evolution; Humanities and Social Sciences; Intermetallic compounds; Metal sulfides; Metals; Modelling; multidisciplinary; Nickel; Oxygen; Oxygen evolution reactions; Oxygen exchange; Reconstruction; Science; Science (multidisciplinary); Spectroscopy; Substitution reactions; Sulfides; Sulfur; Transmission electron microscopy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-37751-y

Dynamic reconstruction of metal sulphides during electrocatalytic oxygen evolution reaction (OER) has hampered the acquisition of legible evidence for comprehensively understanding the phase-transition mechanism and electrocatalytic activity origin. Herein, modelling on a series of cobalt-nickel bimetallic sulphides, we for the first time establish an explicit and comprehensive picture of their dynamic phase evaluation pathway at the pre-catalytic stage before OER process. By utilizing the in-situ electrochemical transmission electron microscopy and electron energy loss spectroscopy, the lattice sulphur atoms of (NiCo)S
1.33
particles are revealed to be partially substituted by oxygen from electrolyte to form a lattice oxygen-sulphur coexisting shell surface before the generation of reconstituted active species. Such S-O exchange process is benefitted from the subtle modulation of metal-sulphur coordination form caused by the specific Ni and Co occupation. This unique oxygen-substitution behaviour produces an (NiCo)O
x
S
1.33-x
surface to reduce the energy barrier of surface reconstruction for converting sulphides into active oxy/hydroxide derivative, therefore significantly increasing the proportion of lattice oxygen-mediated mechanism compared to the pure sulphide surface. We anticipate this direct observation can provide an explicit picture of catalysts’ structural and compositional evolution during the electrocatalytic process.
Dynamic reconstruction of metal sulphides during electrocatalytic oxygen evolution reaction is a key aspect of study. Herein, modelling on a series of cobalt-nickel bimetallic sulphides, the authors reveal a dynamic phase evaluation pathway and the S-O substitution process occurring on the catalytic surface at the pre-catalytic stage.