Assessment of visible light sensitive La-doped BiOBr/ZnO for the effective degradation of malachite green dye

Abstract

Environmental scientists across the globe are actively focused on developing novel materials to remove hazardous wastes from aqueous environments. Among the several methods available, photocatalysis stands out as a very efficient and environmentally beneficial process for removing organic dyes from wastewater. The present work involved the successful fabrication of lanthanum-doped bismuth oxy bromide/zinc oxide (La-doped BiOBr/ZnO, LBZ) as a photocatalyst through a facile hydrothermal technique. The synthesized LBZ composite exhibited enhanced photocatalytic degradation efficiency towards the malachite green (MG) dye molecules under visible light. The synthesized materials were characterized by different analytical techniques like FTIR, XRD, SEM, EDX, XPS, LC-MS, UV–Vis DRS, PL spectra, and mapping analysis, respectively. Various contributing factors, including irradiation time, solution pH, catalyst dosage, and initial dye concentration, were optimized using the batch mode for the maximum efficiency of the prepared catalyst. The prepared LBZ exhibited a bandgap energy of 2.78 eV as determined through UV–Vis DRS analysis. Among the prepared series of catalysts, the LBZ composite could degrade 99 % MG with a minimum irradiation time of 50 min under visible light irradiation. The involvement of h+ and O2− radicals proved to be significant during the degradation process of MG. Additionally, a proposed mechanism for the effective degradation of the photocatalytic degradation of MG was discussed, and successfully identified the mechanism pathway of MG was by employing LC-MS analysis. This investigation highlights the potential of prepared LBZ composite as an effective photocatalyst for removing toxic dye molecules commonly present in industrial effluents.