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.