Morphologically tailored CuO nanostructures toward visible-light-driven photocatalysis

Nanostructures of transition metal oxides, such as copper oxide (CuO), are attractive for their stability and cost-effectiveness. This work reveals that the precursor materials play a crucial role in tailoring the morphologies, properties of CuO nanostructures. Herein, three different copper precursors, such as copper acetate, copper chloride, and copper nitrate, have been used to prepare CuO nanostructures. We find that nanosphere morphology is formed when copper acetate and copper chloride are used, whereas nanoflower morphology is formed when copper nitrate is used as precursors. The synthesis of flower-like CuO nanostructures is attained by altering the precursor material alone, and the petals of these flowers have a thickness of around 50 nm. The photocatalytic properties of the CuO nanoparticles prepared with the different precursors are investigated for the degradation of methylene blue dye. At a certain dye concentration level, the small size of particles results in a higher surface-to-volume ratio, which causes an increase in the number of active surface sites. Owing to the lowest particle size, CuOsphere-A (copper acetate) performs the best photodegradation efficiency. Additionally, the nanoflower-like structure could provide better accessibility of the reactants on the surface of photocatalytic material, resulting in more favorable for the photodegradation.