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).