Construction of metal–organic framework ZIF-8-derived heterostructured ZnO/BiVO4 for enhanced photocatalytic degradation of carbamazepine

Abstract

The fabrication of heterojunctions effectively modulates the physicochemical and photochemical properties of photocatalysts. However, the light absorption of heterojunctions and delivery performance of charge carriers between interfaces are limited by the material preparation method and interface contact form. In this study, facile in situ preparation of ZIF-8 on BiVO₄ and subsequent calcination of the precursor were performed to synthesize ZnO/BiVO₄ heterojunctions successfully. The photocatalytic ability of ZnO/BiVO₄ heterojunctions was estimated adopting carbamazepine (CBZ) as a simulated pollutant. Exploiting the strong chemical bond and close contact at the interfaces, the ZnO/BiVO₄ composite exhibited significantly improved photocatalytic degradation ability for CBZ with a rate constant of 0.0145 min⁻¹, which was around 5.58 and 4.53 times that of a single BiVO₄ and ZnO, respectively. A prominent role of ˙O₂⁻ and ˙OH in the degradation performance of CBZ was identified by radical trapping and EPR analysis, and the satisfactory photocatalytic degradation ability of ZnO/BiVO₄ was attributed to charge transfer mechanisms of type II and Z schemes. Promising heterojunction photocatalysts with compact interface contact were developed in this study using an in situ growth-calcined technique for wastewater remediation.