Band structure engineering of bioinspired Fe doped SrMoO4 for enhanced photocatalytic nitrogen reduction performance

Photocatalytic nitrogen reduction reaction (NRR) for the green synthesis of ammonia is a promising alternative way to the energy-intensive Haber-Bosch process. In this study, we report Fe doped SrMoO4 by a solvothermal method for solar nitrogen reduction. It is found that Fe doping significantly changes the intrinsic bandgap of SrMoO4 and extends the light absorption from UV light to visible light region. At optimal doping concentration, the Fe doped SrMoO4 shows enhanced photocatalytic nitrogen reduction performance compared to the pristine SrMoO4 in ultrapure water. The enhancement is ascribed to the optimized defect states, newly formed Fe–Mo active centers, and extended light absorption range. The characterization results show that Fe doping with optimal concentration not only prohibits the fast recombination of photoinduced charge carriers, but also promotes the interfacial charge transfer. The narrowed intrinsic bandgap enables the Fe doped SrMoO4 to absorb more solar light while keeps the thermodynamic activity to nitrogen reduction with appropriate band energetics. The present study provides an effective strategy for the design of active nitrogen fixation photocatalysts.