Surface Reconstruction of Co 4 N Coupled with CeO 2 toward Enhanced Alkaline Oxygen Evolution Reaction.

Constructing the active interface in a heterojunction electrocatalyst is critical for the electron transfer and intermediate adsorption (O*, OH*, and HOO*) in alkaline oxygen evolution reaction (OER) but still remains challenging. Herein, a CeO 2 /Co 4 N heterostructure is rationally synthesized through the direct calcination of Ce[Co(CN) 6 ], followed by thermal nitridation. The in situ electrochemically generated CoOOH on the surface of Co 4 N serves as the active site for the OER, and the coupled CeO 2 with oxygen vacancy can optimize the energy barrier of intermediate reactions of the OER, which simultaneously boosts the OER performance. Besides, electrochemical measurement results demonstrate that oxygen vacancies in CeO 2 and optimized absorption free energy originating from the electron transfer between CeO 2 and CoOOH contribute to enhanced OER kinetics. This work provides new insight into regulating the interface heterostructure to rationally design efficient OER electrocatalysts under alkaline conditions.