Synergistic effects of heterojunction graphene oxide nanocomposites in photocatalytic degradation of norfloxacin and hydrogen generation via water splitting

Norfloxacin (NOFX), a common fluoroquinolone antibiotic, has recently raised significant concerns due to its adverse effects on both humans and the aquatic environment. In this work, a CuS-ZnS p-n heterojunction was introduced with graphene oxide (GO) sheets using a simple solvothermal technique. ZnS nanoparticles (NPs) have a hexagonal crystal phase and a cubic morphology. In contrast, CuS NPs have a cylindrical shape, and GO has wrinkled flakes. Under visible light, the ZnS/CuS/GO nanocomposite's exceptional hydrogen generation rate and remarkable photodegradation properties were caused by its variable bandgap. It was discovered that the optimal conditions for NOFX drug's breakdown were 50 mg of catalyst and 10 ppm of drug concentration at 30 °C, pH 10, and 300 W Xenon light. The efficiency of drug degradation rose from around ~ 19% to about ~ 86% which is consistent with first-order reaction kinetics. Nanocomposite has outstanding structural stability and can be recycled 5 times, with a noticeable decrease in photocatalytic effectiveness from ~ 86% to ~ 80%. Additionally, to assess the hydrogen production efficiency of the synthesised samples in the presence of sodium thiosulphate, which served as the sacrificial agent, photocatalytic water splitting tests were conducted. Hydrogen generation efficiency was found to be minimum for ZnS (276 µmol/g/h) in 120 min, which was enhanced to 452 µmol/g/h for ZnS/CuS/GO nanocomposite.