Hierarchical defect-rich flower-like BiOBr/Ag nanoparticles/ultrathin g-C3N4 with transfer channels plasmonic Z-scheme heterojunction photocatalyst for accelerated visible-light-driven photothermal-photocatalytic oxytetracycline degradation

For degradation of high-toxic oxytetracycline, defect-rich flower-like BiOBr is prepared and then is combined with both Ag nanoparticles and ultrathin g-C3N4 to construct a plasmonic Z-scheme heterojunction. The results manifest Ag nanoparticles transfer the pathway of the photo-generated carriers and generate a hierarchical plasmonic Z-scheme, leading to the generation of stronger center dot OH besides center dot O2- and h+ for efficient removal of oxytetracycline. During the visible-light photocatalysis process, the removal and mineralization rate of oxytetracycline can respectively achieve 91.7% and 56.2% in 60 min, and the pseudo-first-order rate constant reaches 33.8 min- 1 x 10-3, which is more remarkable than others. Meanwhile, the excellent reusability and stability of the catalyst are verified by cycle-degradation experiments, ICP-OES, X-ray diffraction and Electron spin resonance. It is considered the typical plasmonic Z-scheme, special morphology and surface oxygen vacancies work together to form a spatial hierarchical framework, leading to the extraordinary performance, even causing the photothermal effect to stimulate the activity of the Z-scheme photocatalyst. Furthermore, the degradation pathways of oxytetracycline and the photocatalytic mechanisms are particularly analyzed as well.