A 3D Z-Scheme Heterojunction Photocatalyst: Flower-Like Ag/AgBr/Zn3V2O7(OH)2·2H2O and its Enhanced Visible-Light Photocatalytic Activities

In this work, a 3D Z-scheme photocatalyst Ag/AgBr/Zn 3 V 2 O 7 (OH) 2 ·2H 2 O (Ag/AgBr/ZVO) was synthesized by a hydrothermal method, and a subsequent surface deposition-optical reduction technique. The prepared flower-like Ag/AgBr/ZVO was characterized by scanning election microscopy (SEM), x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy (XPS), UV-vis spectrophotometry, N 2 adsorption-desorption isotherm based on Brunauer-Emmett-Teller (BET) theory, and electrochemical tests. The photocatalytic degradation performance of the catalyst was investigated by the degradation of methylene blue (MB) dye by visible light irradiation. Compared with bare Zn 3 V 2 O 7 (OH) 2 ·2H 2 O (ZVO) nanoflowers, the photocatalytic effect of the 3D Z-scheme heterojunction Ag/AgBr/ZVO was significantly enhanced. The catalyst of 2h-Ag/AgBr/ZVO exhibited the strongest photocatalytic activity, of which the MB degradation rate is about 98.8% in 100 min, which was about five times that of pure ZVO. The increase in the photodegradation rate is ascribed to the accelerated interface charge-transfer process, the faster photogenerated carrier separation rate and the enhancement of visible light absorption. In view of the trapping of the reaction intermediate and the electron spin resonance (ESR) measurement, we propose a possible Z-scheme photocatalytic mechanism. This improved visible-light response likely originates from a synergistic effect of the different components. This work offered an ideal method for producing stable, efficient, and recyclable photocatalysts suitable for use in the visible light range.