Engineering sulfur doped flower-like BiOBrxI1-x solid solutions for strengthened photocatalytic activities

In this work, a series of S-doped BiOBr x I 1-x solid solutions are fabricated via a simple and rapid solvothermal process. Various characterization techniques are used to thoroughly investigate the as-fabricated solid solutions . Interestingly, compared to BiOBr x I 1-x , S-doped BiOBr x I 1-x solid solutions exhibit a loose flower-like structure comprised of thinner nanosheets , which contributes to the enhanced specific surface area , as assessed by Brunauer-Emmett-Teller analysis. Furthermore, S-doped BiOBr x I 1-x solid solutions reveal boosted visible-light response and rapid separation of photoinduced charge carriers, as verified by optical, photo-electrochemical, and electrochemical analysis . These lead to superior visible-light photocatalytic properties of S-doped BiOBr x I 1-x solid solutions on pollutant removal, N 2 fixation, and microplastic degradation. The crystal structure, morphology, and photocatalytic stability of the prepared samples are demonstrated by comparing their X-ray diffraction patterns , scanning electron microscopy images, and photocatalytic degradation as well as nitrogen reduction performance before and after six catalytic recycles. Furthermore, based on Density Functional Theory simulations, significant modifications in the band gap of BiOBr x I 1-x solid solutions occur as iodine content increases while sulfur doping further refines the electronic features, which aligns with the results of Tauc plots. This research proves that S doping is a viable strategy for modulating the electronic structures of BiOBr x I 1-x solid solutions for improving its photocatalytic performance, and provides a new route for optimizing the bandgaps of semiconductors via the non-metallic doping strategy. A series of S-doped BiOBr x I 1-x solid solutions are constructed for the first time. The strengthened photocatalysis on contaminants removal, microplastic degradation, and nitrogen fixation as well as the relevant mechanism are systematically confirmed via experimental characterizations and DFT calculations. • S-doped BiOBr x I 1-x solid solution photocatalysts are constructed for the first time. • Improved photocatalysis is verified by pollutants/microplastic degradation and N 2 reduction. • Photocatalytic mechanism is analyzed by experimental characterizations and DFT calculations. • S doping can effectively optimize electronic and optical properties of BiOBr x I 1-x solid solution. • The prepared samples show good stability in recycle tests of XRD, SEM, and photocatalysis.