Tailoring the electronic structure of ultrathin 2D Bi3O4Cl sheets by boron doping for enhanced visible light environmental remediation

Ultrathin 2D Bi3O4Cl nanosheets are promising photocatalysts for photocatalytic organic pollutions degradation, and tailoring the electronic structure by non-metal element doping of Bi3O4Cl is an important strategy to increase its photocatalytic activity. However, the role of doped non-metal atoms on charge carriers separation and light absorption has not been understood in depth. Here, the B-doped Bi3O4Cl ultrathin nanosheets are fabricated via a solvothermal way, which increase solar absorption and electron-hole separation of Bi3O4Cl. The products are characterized by FE-SEM, TEM, AFM, indicating that B-doped Bi3O4Cl are 3.87 nm thick nanosheets. And UV–Vis-DRS, XPS, PL and density functional theory show that the doped B atoms play multiple roles in facilitating photocatalytic performance: (1) inducing midgap states to immensely expand the light response region up from 450 nm to 557 nm; (2) acting as the electron capture centers to accelerate charge carries separation. The ESR technology shows that B-doped Bi3O4Cl can produce more O2– and OH radicals. As a result, the B-doped sample achieves a high-efficient photocatalytic bisphenol A and ciprofloxacin degradation, 3-fold and 2.1-fold higher than pure Bi3O4Cl, respectively. This work presents new opinions into the design of photocatalyst and confirms the role of electronic structure modulation on tuning catalytic activity.