The Synthesis Of AgBr/Bi₂WO₆ Heterojunctions And The Study On Their Photocatalytic Performance

Industrialization and urbanization brought about both the fast development of economy and society and the serious water pollution.Dyes,antibiotics and other harmful organic pollutants discharged into the water body in large quantities,causing serious threats to the ecosystem and human survival.Photocatalytic technology had attracted wide attention in the field of environmental remediation due to its green and efficiency,but poor light absorption capacity and low quantum efficiency were still the two difficult problems to be solved in the field of photocatalysis.Taking the Bi₂WO₆-based photocatalytic system with visible light response as the main line,the light absorption ability and the separation efficiency of photogenerated carriers in Bi₂WO₆were enhanced through morphology regulation and heterojunction construction in this study,thus achieving efficient photocatalytic performance.（1）the three-dimensional hierarchical flower-like Bi₂WO₆ was synthesized by a simplified hydrothermal.The scanning electron microscope（SEM）,X-Ray Photoelectron Spectroscopy（XPS）and X-ray diffraction（XRD）were adopted to characterize the morphology,composition and structure of the as-prepared material.The performance experiment results showed that the photodegradation efficiency for tetracycline（TC）,enrofloxacin（ENR）and rhodamine b（RhB）of flower-like Bi₂WO₆reached 60.43%,62.70%and 50.06%,respectively.（2）The different proportions of AgBr nanoparticles were loaded onto the surface of hierarchical flower-like Bi₂WO₆ by deposition-precipitation method to obtain Z-scheme AgBr/Bi₂WO₆ heterojunction photocatalyst.SEM diagram showed that AgBr nanoparticles with significantly reduced size were uniformly loaded onto the surface Bi₂WO₆ flower-like spheres.The target pollutant TC was selected to evaluate the photocatalytic performance.AgBr（20 wt%）/Bi₂WO₆ displayed the optimal TC removal efficiency（87.5%）within 60 min of visible light illumination.No obvious decrease in photocatalytic performance was observed after four cycles.Besides,The effects of TC initial concentration,p H、coexisting ions and light conditions on the photocatalytic degradation of TC were investigated in detail.（3）The photodegradation mechanism of AgBr/Bi₂WO₆ heterojunction towards TC was further investigated.Radicals trapping experiment and electron spin resonance（ESR）results demonstrated that·OH and·O₂^–played the important part in the photodegradation of TC.Three-dimensional excitation-emission matrix fluorescence spectroscopy（3D EEMs）and liquid chromatography-mass spectrometry（LC-MS）analyses shed light on the mineralization behavior and the detailed decomposition pathway of TC.The excellent photocatalytic performance AgBr/Bi₂WO₆heterojunction could be ascribed to the synergistic effect of the flower-like structure Bi₂WO₆,electron mediator Ag nanoparticles（Ag NPs）and Z-scheme heterojunction charge transfer mechanism,which enhanced the light harvest capability,separation efficiency of photo-generated carriers and redox ability.