PHOTOCHEMICAL SYNTHESIS OF CU-MODIFIED ZnO UNDER DIFFERENT LIGHT INTENSITIES FOR ENHANCED METHYLENE BLUE DEGRADATION

Cu-modified ZnO photocatalysts were synthesized by a light-intensity-assisted photochemical method using irradiation intensities of 100–400 mW cm⁻². Their photocatalytic performance was evaluated through methylene blue degradation under visible light. XRD confirmed that the hexagonal wurtzite structure of ZnO was preserved after Cu modification, while XRF and EDS verified the successful incorporation of copper without detectable crystalline secondary phases. The catalyst synthesized at 200 mW cm⁻² exhibited the highest activity, achieving 89.78% methylene blue degradation within 60 minutes and a pseudo-first-order rate constant of 0.03664 min⁻¹. The results demonstrate that controlling irradiation intensity during photochemical synthesis is an effective strategy for optimizing Cu-related active sites and improving the visible-light photocatalytic performance of ZnO.