Oxyanion-Coordinated Co-Based Catalysts for Optimized Hydrogen Evolution: The Feedback of Adsorbed Anions to the Catalytic Activity and Mechanism

In order to achieve high-efficiency hydrogen production, researchers always focus on the catalyst itself but rarely consider the feedback of corresponding component spillover and re-adsorption in the catalyst to the reaction activity. This work investigates the promoting effect of vanadium species on the hydrogen evolution reaction (HER) performance of Co3O4. Multiple characterizations indicate that VOx dissolves during the HER and exists in 1.0 M KOH as VO43-. In situ Raman spectroscopy and experimental results show that Co3O4 will be converted to Co(OH)2 and bound to free VO43- through O atoms (Co-O-VO43-), which acts as the active center of HER. More oxygen vacancies (Ov) are also generated on the catalyst surface. The extra addition of VO43- to the electrolyte can not only repair the durability of Co3O4 but also promote the HER activity of Co5.47N, Co3S4, and Co(OH)2. The findings in this work contribute to an in-depth understanding of the structural transition mechanism and activity origin of catalysts under reaction conditions.