Improved sunlight-driven photocatalytic abatement of tetracycline and photoelectrocatalytic water oxidation by tin oxide quantum dots anchored on nickel ferrite nanoplates

In this study, nickel ferrite (NiFe2O4) was prepared by a simple wet chemical procedure followed by calcination, and tin oxide (SnO2) quantum dots (SQDs) were prepared by a chemical reduction approach. Additionally, a NiFe2O4-SQD (NF-SQDs) nanocomposite was prepared by a hydrothermal approach. The NF-SQDs nanocomposite was analyzed using several techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), and electrochemical investigations. The NF-SQDs nanocomposite showed promising properties for use as a novel nanomaterial in the degradation of the water pollutant, tetracycline (TC), and was used for photoelectrochemical (PEC) water oxidation. The successful preparation of the NF-SQDs nanocomposite was confirmed by XRD, SEM, TEM, and DRS. Morphology analysis confirmed the successful decoration of SQDs on the NiFe2O4 nanoplates. The bandgap of the NF-SQDs nanocomposite was modified because of the formation of a heterojunction. The NF-SQDs nanocomposite degraded TC within 70 min under simulated sunlight irradiation and effectively separated the photogenerated charge carriers to improve the degradation efficiency. Detailed PEC investigations revealed a low charge-transfer resistance, excellent photocurrent response, and high stability of the NF-SQDs nanocomposite. The detailed potential mechanisms for the photocatalytic degradation of TC and PEC water oxidation are discussed herein with schematics.