Synthesis, characterization and application of supported cobalt oxide natural light active photocatalyst

Industrial revolution has increased levels of pollutants in the surroundings causing harm to aquatic life and drinking water. So in the present work, natural light active cobalt oxide photocatalyst was synthesized to treat waste water. Co₃O₄ powder and Co₃O₄ supported on ZrO ceramic substrate were prepared by sol–gel technique using cobalt nitrate as precursor. Co₃O₄ powder was calcined at different temperatures from 350 ºC–600 ºC and the optimum temperature was found to be 350 ºC. Hence cobalt oxide was deposited on ZrO at 350 ºC. Photocatalytic degradation of methylene blue (MB) dye was investigated by using Co₃O₄ supported on ZrO under natural sunlight irradiation. Characterization was done by using XRD, Zeta-particle size analyzer, BET and SEM-EDAX. XRD analysis showed that cobalt particles formed were in pure phase. The surface area of supported catalyst was found to be 37.42 m²/g and pore volume was 0.0078 cc/g. Zeta and particle size analysis revealed that the Co3O4 powder was neutral in charge and average particle size was found to be 747 nm. The concentration of MB was measured by UV-vis spectroscopy and degradation of 90% was observed after exposing it to natural light irradiation for 4 hrs. The kinetic study of degradation showed that the degradation followed first order kinetics.