Highly active g-C3N4 photocatalysts modified with transition metal cobalt for hydrogen evolution

Abstract

Developing highly effective photocatalytic hydrogen production in graphitic carbon nitride (g-C₃N₄) is still a challenging issue. Herein, for the first time, the structural engineering of g-C₃N₄ nanosheets with Co atoms bonded with compositional N (Co–N_x) is demonstrated to address this challenge. The structure of Co–N_x is formed through the substitution of C atoms in g-C₃N₄ with Co atoms, which is evidenced by X-ray absorption fine structure spectroscopy (XAFS). Therefore, by adjusting the band structure and electronic structure of g-C₃N₄, the separation and transfer efficiencies of photo-generated charges are significantly improved. Consequently, the catalysts exhibit a superior visible light photocatalytic hydrogen production rate (5394.35 μmol g⁻¹ h⁻¹) and the apparent quantum efficiency (AQE) of 1.92% at 427 nm.