Photocatalytic degradation of methylene blue dye under visible light irradiation by CBTS photoactive catalysts as a function of annealing temperature
摘要
In this work, Cu2BaSnS4 (CBTS) thin films were synthesized on ITO conductive glass substrate via a sol-gel dip-coating method and investigated for their photocatalytic performance in degrading methylene blue (MB) under visible light irradiation. The effects of annealing temperature on film morphology, crystallinity, and optical properties were systematically studied. The film optimized at an annealing temperature of 500 °C exhibited a compact morphology with moderate agglomeration, which favors enhanced light absorption and provides a higher density of active sites for photocatalytic activity. X-ray diffraction and Raman spectroscopy confirmed the formation of single-phase CBTS, while UV-Vis analysis revealed a direct bandgap of approximately 1.84 eV. X-ray photoelectron spectroscopy analysis confirmed the presence of Cu+, Ba2+, Sn4+, and S2− oxidation states, validating the chemical composition and purity of the CBTS phase for all the annealed samples. Photocatalytic tests showed a maximum MB degradation efficiency of 91.8% within 60 min under visible light. Scavenger experiments identified photogenerated holes as the dominant reactive species. These findings highlight the potential of CBTS thin films as efficient visible-light-active photocatalysts for wastewater treatment applications.