Integration of 2D graphene oxide/zinc oxide nanohybrid for enhancement adsorption and photodegradation of organic pollutants

The band gap plays a critical role in determining the photocatalytic efficiency of semiconductor catalysts. Zinc oxide (ZnO) photocatalysts have gained significant attention in sustainable energy and environmental pollution remediation. However, despite its potential, ZnO photocatalytic performance has been hindered by its wide band gap and rapid charge carrier recombination. Numerous techniques have been created to tackle this problem, including doping, nanostructuring, creating oxygen defects, surface modification, and utilizing hybrid nanomaterials. The ZnO and ZnO@GO with different GO contents were synthesized using uncomplicated co-precipitation and solid-state reaction techniques. The ZnO@GO possesses bandgap (Eg) values of 2.5 eV, which is advantageous for achieving more significant photocatalytic activity compared to the unadorned ZnO with Eg values of 3.24 eV. This study investigated the effectiveness of the synthesized catalysts in treating methylene blue (MB) dye through visible light-induced photoreaction. The ZnO@GO nanohybrid exhibited remarkable performance, achieving a decomposition rate of 98.4 % for MB within a 22-minute timeframe. The rate constant of 0.1343 min⁻¹ is significantly greater than that of the unadorned ZnO 0.0448 min⁻¹. Graphene oxide (GO) plays a crucial role in the photocatalytic process by facilitating the gathering and transportation of electrons. This enhancement generates reactive oxygen species and hydroxyl radicals, effectively breaking down MB. The scavenger test results provided compelling evidence that the degradation of MB primarily occurred due to the presence of hydroxyl radicals, which were identified as the most active species in this process.