2025/07/07 by Lanjewar, Mangesh K., Mahadwad, Omprakash K., Patil, Pritam
Energy · Materials Science · #Advanced Photocatalysis Techniques #TiO2 Photocatalysis and Solar Cells #Copper-based nanomaterials and applications
paper · doi:10.57647/ijc.2026.1601.05
Pure TiO2, ZnO, ZnO/TiO2, and Cu doped ZnO/TiO2 (Cu:ZnO/TiO2) heterojunctions (Type II) photocatalysts were successfully synthesized using a cost-effective room-temperature sol-gel (RTSG) method. Copper (Cu) doping levels ranged from 3 to 9 wt% relative to ZnO. The structural, morphological, optical, and surface chemical properties were characterized using XRD, FESEM, UV–Vis spectroscopy, XPS, and FTIR. Among all samples, 7 wt% Cu:ZnO/TiO2 exhibited a prominent red shift in the absorption edge (from 388.7 to 413.33 nm) and a narrowed band gap of 3.0 eV compared to 3.19 eV for pure TiO2, indicating enhanced visible-light absorption. This optimized photocatalyst demonstrated outstanding photocatalytic efficiency for the first-time degradation of Turquoise Blue G (TBG) dye, achieving 95% degradation within 2.5 h under UV irradiation-1.52 times higher than pure TiO2. The Chemical Oxygen Demand (COD) decreased by 77.78%, confirming effective mineralization. Kinetic analysis revealed that the degradation followed pseudo-first-order kinetics, validating the reaction’s rate dependence on dye concentration. The recycled photocatalyst retained 84.3% degradation efficiency and 60% COD reduction, indicating excellent reusability. Furthermore, the highest adsorption capacity was observed at lower pH (pH 4), favoring electrostatic attraction. These results establish 7% Cu:ZnO/TiO2 as a robust, reusable, and highly efficient photocatalyst for sustainable dye wastewater treatment.