Rational design and improved visible-light-driven photocatalytic efficacy of NiO-PbBiO2Br p-n heterojunction for degrading tetracycline in wastewater: DFT simulation and mechanism insight

In this study, a NiO-PbBiO 2 Br photocatalyst was developed by a simple chemical precipitation approach followed by a hydrothermal process to eliminate tetracycline (TC). The resultant materials were assessed utilizing diverse characterization techniques. Compared with pure PbBiO 2 Br (49.5 %) and NiO (56.8 %), the NiO-PbBiO 2 Br composite exhibited superior photocatalytic effectiveness for removing TC under visible light and achieved a remarkable 98.4 % elimination of TC within 70 min (conditions: [TC] = 10 mg/L, pH 7 and [catalyst] = 1 g/L). The reaction rate constant (K) values are in the following order: NiO-PbBiO 2 Br (0.0591 min −1 ) > NiO (0.0119 min −1 ) > PbBiO 2 Br (0.0097 min −1 ). The markedly improved photocatalytic efficiency of NiO-PbBiO 2 Br can be ascribed to the expanded light absorption and the establishment of p-n heterojunction amid NiO and PbBiO 2 Br. The effects of several important factors, e.g. TC concentration, pH, catalyst dosage, and different water sources, were thoroughly investigated. Cycle tests were performed to confirm the stability and reusability of NiO-PbBiO 2 Br. Furthermore, electron spin resonance (ESR) and radical scavenging studies verified that the species •O 2 − , h + , and •OH play a key role in removing TC. The susceptible active regions of TC and the probable TC degradation routes were examined through density functional theory (DFT) calculations and high-performance liquid chromatography (HPLC) analyses. Thus, this work presents a new methodology for creating a photocatalyst with enhanced photocatalytic effectiveness for removing organic pollutants in water.