| Institution: | 1. Department of Chemistry, School of Science, Institute of Molecular Plus, Tianjin University, Tianjin, 300072 China
These authors contributed equally to this work.;2. Department of Chemistry, School of Science, Institute of Molecular Plus, Tianjin University, Tianjin, 300072 China;3. Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, 450000 China |
| Abstract: | Transition metal chalcogenides (TMCs) are efficient oxygen evolution reaction (OER) pre-electrocatalysts, and will in situ transform into metal (oxy)hydroxides under OER condition. However, the role of chalcogen is not fully elucidated after oxidation and severe leaching. Here we present the vital promotion of surface-adsorbed chalcogenates on the OER activity. Taking NiSe2 as an example, in situ Raman spectroscopy revealed the oxidation of Se-Se to selenites (SeO32−) then to selenates (SeO42−). Combining the severe Se leaching and the strong signal of selenates, it is assumed that the selenates are rich on the surface and play significant roles. As expected, adding selenites to the electrolyte of Ni(OH)2 dramatically enhance its OER activity. And sulfates also exhibit the similar effect, suggesting the promotion of surface-adsorbed chalcogenates on OER is universal. Our findings offer unique insight into the transformation mechanism of materials during electrolysis. |
