Tuning the electronic properties of Bi₂MoO₆ by S-doping to boost efficient photocatalytic nitrogen fixation reactions

Doping elements in photocatalysts is a reliable strategy for efficiently utilizing solar energy. Herein, we reported the successful synthesis of S-doped Bi2MoO6 (S-BMO) through a facile one-step solvothermal method utilizing Na2S as a sulphur source. By systematically adjusting the doping concentration of S2- ion, it was found that when the optimal doping amount of Na2S was 0.7 %, the obtained photocatalyst showed a photocatalytic nitrogen fixation rate of 122.14 mu mol center dot h-1 center dot gcat-1 under visible light irradiation for 1 h, which was 3.67 times better than Bi2MoO6 (BMO). Density Functional Theory (DFT) calculations demonstrated that S partially substituted O in BiO-Mo in S-BMO and also modulated the electronic structure of BMO. The photoreduction ability was enhanced due to the upshift of the conduction band (CB) energy level from -0.6 to -0.72 eV after S doping. This work may provide a promising method for efficient photocatalytic nitrogen fixation by doping BMO with non-metallic elements.