Interfacially bonded Co-N boosts photocatalytic H2 evolution in a closely coupled CoFe2O4/g-C3N4 composite structure

To create hybrid composites for highly effective photocatalytic hydrogen evolution reactions, the photogenerated charge separation efficiency at the hybrid interface and the surface reaction kinetics at the reactive sites are key factors. In this work, CoFe hydroxide nanosheets prepared by dealloying were first mixed with graphitic carbon nitride (g-C3N4) to synthesize a CoFe2O4/g-C3N4 composite with strong Co-N bonds at the interface by a simple hydrothermal method. It was found that the presence of Co-N bonds between the components in the composites enhances the separation and transfer by photogenerated carriers at the composite interface. Furthermore, the presence of Co-N bonds enhanced the synergistic effect of the hybrid, which significantly boosts their photocatalytic performance in comparison to their counterparts. Under full-spectrum light, the composite photocatalyst has a greater efficiency of photocatalytic water H2 evolution (6.793 mmol/g−1·h−1) and exceptional stability when compared to pure g-C3N4 (0.236 mmol/g−1·h−1) and CoFe2O4 (0.088 mmol/g−1·h−1). Under visible irradiation, the photocatalytic activity of the composite (0.556 mmol/g−1·h−1) for H2 evolution increased by factors of 28.37 and 75.8 when compared to pure g-C3N4 and CoFe2O4, respectively.