Cobalt Oxide Supported on Phosphorus-Doped g-C₃N₄ as an Efficient Electrocatalyst for Oxygen Evolution Reaction

Cobalt oxides have been paid much attention in oxygen evolution reaction (OER). To enhance the catalysis reaction performance, here we reported Co₃O₄ nanocrystals anchored on phosphorus-doped carbon nitride (P-CN) sheets via Co-N bonds for highly efficient OER. By simply sintering the mixture of Co₃O₄ nanocrystals with P-CN sheets in the tube furnace, the Co-N bonds were well-formed as indicated by X-ray photoelectron spectroscopy analysis, forming efficient charge transfer channels to conquer the barriers between glassy carbon electrode surface and Co₃O₄ active sites. The Co₃O₄ nanocrystals distributed on the P-CN substrates homogeneously and exposed most of the potential active sites of Co₃O₄ during electrochemical processes. Because of the synergy between Co₃O₄ and P-CN, the OER performance of as-fabricated Co₃O₄/P-CN catalyst showed the lowest overpotential (320 mV), the lowest Tafel slope (66.8 mV dec^-1), and the highest electrochemical active surface area (ESCA, 133.58 mF cm^-2).