Green synthesis of cobalt oxide nanoparticles using Citrus medica leaves extract: Characterization and photo-catalytic activity

The study deals with the green and eco-friendly synthesis and characterization of cobalt oxide nanoparticles using leaf extract of Citrus medica plant. The crystalline nature and functional groups analysis of cobalt oxide Nps was confirmed by X-ray diffraction and diffused reflectance infra-red spectroscopy respectively. The band gap of the Nps was calculated using Tauc plot. Scanning microscope analysis was carried out to get an insight to the structural morphology of the catalyst. The catalyst was found to be very active for the degradation of methyl orange dye using a very small amount of catalyst (0.006 g) using ultra violet radiation source. Approximately, 90% of the dye (Initial Conc. 10 mg L^-1) was degraded in 60 min at natural pH (6.5). The dye degradation increased with increase in pH of the solution, due to the enhanced production of OH radicals, at higher pH values. Different experimental parameters like catalyst amount, agitation speed, initial pH of the solution, initial concentration of dye and recycling of the catalyst were varied to test the performance of the catalyst.