Kinetically controlled selective synthesis of Cu2O and CuO nanoparticles toward enhanced degradation of methylene blue using ultraviolet and sun light

Two different stable forms of copper oxide (Cu2O and CuO) nanoparticles (NPs) were selectively synthesized through a smart approach using the same precursor but different reagent amounts. The fabrication strategy is cost-effective and relatively easy. The bandgap energies of the as-synthesized Cu2O and CuO-NPs, as determined from Tauc plots, are 2.08 and 1.82 eV, respectively. The photocatalytic performance of these NPs was assessed through their use in the photodegradation of an organic-dye water contaminant under UV and solar-light illumination. Methylene blue (MB) was chosen as a representative dye because of its ubiquitous presence in industrial wastewater and its hazardous effects on human health. The results of experiments involving the photodegradation of MB by the synthesized Cu2O and CuO-NPs revealed 97% and 81% photodecomposition efficiencies, respectively, during 60 min of UV-light illumination. When sunlight was used as a light source, and the duration was extended to 120 min, the photodecomposition efficiencies were 70% and 63% for the Cu2O and CuO-NP photocatalysts, respectively. The efficient degradation of MB solution by the as-prepared NPs implies that they are potentially potent photocatalysts for the treatment of wastewater originating from industrial and domestic sources.