Rational design of efficient visible-light photocatalysts (1D@2D/0D) ZnO@Ni-doped BiOBr/Bi heterojunction: Considerations on hierarchical structures, doping and SPR effect

Abstract

• 3D hierarchical Ni-doped BiOBr/Bi suppported ZnO NR is obtained. • 3D hierarchical structure of Z@B/Bi-Ni generates more active sites for photocatalytic reaction.. • Formation of •oxygen vacancies have been achieved by in-situ reduction of Bi and Ni doping. • The photocatalytic mechanism is well discussed based on the experiments and DFT calculations. Simultaneously integrating heterogeneous interface, element doping, and metal decorating was a promising strategy to promote the visible-light-driven photocatalytic activity. Herein, we demonstrated a facile solvothermal route for Ni-doped BiOBr/Bi 0 with ZnO 3D hierarchical heterojunction (denoted as Z@B/Bi-Ni). The optimal photocatalysts of Z@B/Bi-Ni sample presented a remarkable catalytic performance of high concentrations of tetracycline solution (40 mg/L) than those of the Z@B/Bi, Z@B, BOB and ZnO photocatalysts toward the visible-light-driven degradation. The enhanced photocatalytic mechanism can be proposed as follows: (i) 3D hierarchical heterojunction provided more active sites and accelerated the separation of charge carriers for photocatalytic TC; (ii) formation of oxygen vacancies on the surface over Z@B/Bi-Ni by in-situ reduction of Bi 0 and Ni doping could serve as the active sites for oxygen activation to adsorb free O 2 and generate more superoxide radicals; (iii) SPR effect of Bi metal were beneficial to carrier separation and also act as the active site to trap O 2 molecules. This work clarified the role of unique morphologies, surface plasmonic resonance (SPR) effect of metal Bi, and Ni doping in Z@B/Bi-Ni, and its photocatalytic reaction mechanism was proposed by a series of experiments, characterization and DFT calculations, arousing a new perspective to design hierarchical heterojunction photocatalysts.