Photoinduced growth of Cu nanoparticles on ZnO from CuCl2 in methanol

Cu nanoparticles were formed on surface of nano-ZnO by UV light induced photoreduction of CuCl₂ in methanol solution suspended with ZnO nanoparticles. By controlling the reaction conditions, the average size of the produced copper nanocrystal can be fine-tuned in the range of 10–200 nm. At constant UV irradiation, the Cu nanocrystals gradually grew up as the initial concentration of copper cation was increased, showing that the in situ formed Cu nanoparticles act as a bridge to facilitate the transferring of photoexcited electrons from ZnO surface to Cu²⁺ in solution. A Redox property was also proved for the Cu nanoparticles.