Fabrication and characterization of solar active BN coupled with ZnO composite catalysts for efficient photocatalytic detoxification of methyl orange dye under solar and visible light irradiation

Abstract

In this paper, pure ZnO and hexagonal boron nitride (BN) loaded ZnO nanorods were synthesized via a simple hydrothermal method. XRD analysis revealed good crystallinity and hexagonal wurtzite structure of the synthesized materials. FE-SEM images showed the nanorod-like structure of the ZnO material. The UV-DRS spectra showed a decrease in the optical bandgap of BN-ZnO due to the loading of BN. The outcomes from the EIS analysis indicated that the 3% BN-ZnO photocatalyst exhibited the most favorable recombination rate for electron-hole pairs and the least resistance to electron transfer. Photocatalytic evaluation for methyl orange (MO) detoxification under sunlight and visible light illumination revealed that 3% BN-ZnO showed the highest activity, and kinetic studies showed pseudo-first-order degradation. Moreover, the sunlight process outperforms than visible light process, which can be attributed to the ≈ 4% UV radiation available in the solar spectrum. TOC studies confirmed the mineralization of the MO dye. Trapping experiments using various quenchers show that superoxide radicals (O2•−) anion play a major role in the degradation process. Finally, we proposed a plausible photocatalytic mechanism based on our findings.