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

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)-O-center dot 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/NiCr2O4 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.

Automated summary

The study successfully synthesized a novel visible-light-responsive ZnO/NiCr2O4 nanocomposite via a hydrothermal procedure. The nanocomposite exhibited significantly enhanced photocatalytic degradation performance for tetracycline and phenol compared to ZnO and NiCr2O4, attributed to improved visible light absorption and the construction of a p-n heterojunction. The study also identified the predominant active species in the photocatalytic reactions and proposed a possible mechanism based on detailed examination of various characterization techniques.