Synchronous construction of CoS₂ in-situ loading and S doping for g-C₃N₄: Enhanced photocatalytic H₂-evolution activity and mechanism insight

Considering the fact of the cost control in photocatalysis, it is significant to develop the noble-metal-free photocatalysis for H₂ evolution. Herein, CoS₂ in-situ loading and S doping for g-C₃N₄ were synchronously constructed by hydrothermal and sulfidation processes. With systematical physicochemical characterizations, it was found that partial N atoms in g-C₃N₄ were replaced by S atoms, improving the visible-light absorption ability for more generation of photo-generated carriers. CoS₂ as an effective noble-metal-free H₂-evolution cocatalyst induced and captured photo-generated electrons for promoting separation of photo-generated carriers synergistically with S doping. More contact between CoS₂ and g-C₃N₄ were formed by the in-situ growth of CoS₂ nanosheets on the surface of g-C₃N₄ nanosheets. It was important that Co-S bonding between CoS₂ and S-doped g-C₃N₄ was built by the synchronous construction of CoS₂ in-situ loading and S doping, strengthening the directed transfer of photo-generated electrons from S-doped g-C₃N₄ to CoS₂. Accordingly, the synergetic function of CoS₂ in-situ loading and S doping effectively elevated the noble-metal-free photocatalytic activity of g-C₃N₄ for H₂ evolution under visible-light irradiation.