Synthesis and characterization of novel ZnO/NiCr2O4 nanocomposite for water purification by degradation of tetracycline and phenol under visible light irradiation

Abstract Combining semiconductors is considered a rational strategy to improve the photocatalytic performance of conventional photocatalysts. In this work, a novel visible-light-responsive ZnO/NiCr2O4 nanocomposite was successfully synthesized via a hydrothermal procedure. The characterization of products was conducted by different techniques to study optical, structural, and morphological properties. The ZnO/NiCr2O4 nanocomposite performance for photocatalytic degradation of tetracycline (98 %) and phenol (81.4 %) considerably exhibits 4.2 and 1.9 enhancement over ZnO and NiCr2O4, respectively. The ZnO/NiCr2O4 nanocomposite's excellent photocatalytic activity was ascribed to the enhanced visible light absorption and construction of p-n heterojunction, resulting in an effective photogeneration, separation, and transfer of electron-hole pairs into the active sites on photocatalysts. Trapping experiments disclosed that the predominant active species in photocatalytic reactions were ⦁ OH and hole. The data obtained from the results of EIS , M–S test, PL , and trapping experiments were examined in detail, and based on that, a possible mechanism was proposed. Moreover, the ZnO/NiCr 2O4 nanocomposite's durability and reusability were studied by performing 4 consecutive runs. It is hoped that this work will provide insights for researchers in the design, preparation, and use of new and efficient nanocomposites in various photocatalytic processes.