Preparation and enhanced photoelectrochemical performance of coupled bicomponent ZnO-TiO2 nanocomposites

Novel coupled bicomponent nanocomposites consisting of anatase TiO2 nanoparticles and wurtzite ZnO nanorods were prepared using a one-step hydrothermal method, and they were characterized by transmission electron microscopy, X-ray diffraction, and specific surface area. Compared with the mere TiO2 nanoparticles or ZnO nanorods, the coupling of TiO2 nanoparticles and ZnO nanorods produced a significant effect on its properties, such as surface morphologies, surface areas, electronic properties, and photoelectrochemical properties. The generated photocurrent of the coupled ZnO-TiO2 nanocomposite was largely enhanced with several orders of magnitude higher intensities than that of the mere TiO2 nanoparticles or ZnO nanorods. The photocatalytic activities of the coupled TiO2-ZnO nanocomposites, evaluated using the photodegradation of methyl blue as a probe reaction, were also significantly enhanced compared to those of the mere TiO2 nanoparticles or ZnO nanorods. The enhancement of the photocurrent actions and photocatalytic activities might arise from the increased surface area, which can enhance the light harvest and the ability of generating photoinduced electron-hole pairs of active sites, and the favorable electron-transfer properties of the heterojunctions TiO2/ZnO in the coupled ZnO-TiO2 nanocomposites. It is expected that the present work is of notable significance for understanding the unique properties that result from the coupled nanocomposites and designing new nanocomposites of advanced functions in photoelectrochemical applications.