Black Phosphorus-Modified Co₃O₄ through Tuning the Electronic Structure for Enhanced Oxygen Evolution Reaction

Abstract

Spinel Co₃O₄, consisting of two mixed valence states, Co²⁺ and Co³⁺, has attracted enormous interest as a promising electrocatalyst for oxygen evolution reaction (OER). Proper control on the relative proportion of Co²⁺/Co³⁺ in cobalt oxide can greatly tune the electronic structure and further optimize its catalytic performance. Herein, a hybrid coupling Co₃O₄ with black phosphorus (Co₃O₄@BP) is designed as an efficient catalyst for OER. Electron migration from BP to Co₃O₄ is achieved in Co₃O₄@BP, owing to the higher Fermi level of BP than that of Co₃O₄. Efficient electron transfer can not only create massive active sites with abundant Co²⁺ but also remarkably suppress the deterioration of BP. Particularly, the Co₃O₄@BP catalyst outperforms the pristine Co₃O₄ by over four times and is even 20 times higher than that of bare BP at a potential of 1.65 V versus reversible hydrogen electrode. Our finding provides insightful understanding for electronic engineering in Co₃O₄@BP by balancing advantages and utilizing drawbacks of Co₃O₄ and BP.