Oxyanion-Coordinated Co-Based Catalysts for Optimized Hydrogen Evolution: The Feedback of Adsorbed Anions to the Catalytic Activity and Mechanism
Xiao Hui Chen, Ting Li, Xiao Lin Li, Jinglei Lei, Nian Bing Li, Hong Qun Luo
Abstract
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 Co 3 O 4 . Multiple characterizations indicate that VO x dissolves during the HER and exists in 1.0 M KOH as VO 4 3– . In situ Raman spectroscopy and experimental results show that Co 3 O 4 will be converted to Co(OH) 2 and bound to free VO 4 3– through O atoms (Co–O–VO 4 3– ), which acts as the active center of HER. More oxygen vacancies (O v ) are also generated on the catalyst surface. The extra addition of VO 4 3– to the electrolyte can not only repair the durability of Co 3 O 4 but also promote the HER activity of Co 5.47 N, Co 3 S 4, 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.