Synthesis of Cu2O/ZnO hetero-nanorod arrays with enhanced visible light-driven photocatalytic activity

Vertically aligned Cu2O/ZnO hetero-nanorod arrays were synthesized on indium-doped tin oxide (ITO) glass substrates using a simple hydrothermal method followed by an electrodeposition process. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) results show that Cu2O nanoparticles conformably formed on the pre-grown ZnO single-crystalline nanorods. Compared to pure Cu2O and pure ZnO nanorod array films, the Cu2O/ZnO hetero-nanorod array films exhibit an excellent improvement in photocatalytic applications under visible light irradiation. The increase of the electrodeposition time (amount) of Cu2O helps to enhance the photocatalytic activities of the system until the Cu2O nanoparticles nearly cover the entire periphery of the ZnO nanorods. The enhanced photocatalytic activity is attributed to better light scattering for the Cu2O/ZnO hetero-nanorod array structure and fast charge separation and transport within the heterojunctions of the Cu2O/ZnO.