High performance Co₃O₄/Sn-ZnO nanocomposite photocatalyst for removal of methylene blue dye

Abstract

Abstract Methylene blue is a toxic, carcinogenic, and non-biodegradable synthetic dye discharged from factories and industries that causes severe harm to human health and environmental pollution. Therefore, in this work, Co 3 O 4 /Sn-ZnO nanocomposite was synthesized using a simple sol–gel method for efficient photocatalytic removal of methylene blue dye in an aqueous basic medium. The structural, optical, photoluminescence, morphological, and compositional properties were studied. The XRD result revealed that the crystal size increases as the full width at half maxima (FWHM) decreases when Co 3 O 4 are coupled with Sn-ZnO. From UV-visible diffusive reflectance and photoluminescence spectroscopies, a narrowing of the band gap and a reduction of the charge carrier’s recombination rate were observed, respectively. The photocatalytic efficiency and degradation rate constant of 95.1% and 0.03251 min −1 were recorded for methylene blue dye upon the use of optimized catalyst dosage of 60 mg Co 3 O 4 /Sn-ZnO nanocomposite catalyst under an irradiation time of 100 min at room temperature for optimized pH value of 9 in an aqueous basic medium.