Photocatalytic Degradation of MB-Dye by CZTS Catalyst

Copper zinc tin sulfide (CZTS) thin films were prepared by the spin coating technique. The Raman spectrum reveals the kesterite crystal structure of CZTS. Scanning Electron Microscopy (SEM) shows agglomerated surface morphology. The EDAX analysis confirms the presence of all the constituent elements of Cu₂ZnSnS₄. The material with a band gap of 1.92 eV is a promising candidate for the photocatalytic degradation of Methylene Blue (MB)-dye solution, contributing to the eco-friendly wastewater treatment. Photocatalytic activity was studied using a 250 ml MB-dye solution of concentration 10 mg/L. The MB-dye solution containing the CZTS thin-film catalyst placed at the bottom of the beakers was exposed to visible light for irradiation times of 15, 30, 45, 60, 75, 90, 105, and 120 min. The photocatalytic kinetic study showed apparent rate constants of 0.00562 min⁻¹ and 0.00674 min⁻¹ for 2 cm² and 4 cm² catalysts, respectively, and about 46% and 60% degradation were observed after 120 minutes of irradiation. The result confirms that photocatalytic degradation strongly depends on both the thin-film area and the reaction time.