WO₃-ZnO and CuO-ZnO nanocomposites as highly efficient photoanodes under visible light illumination

We prepared ZnO nanocomposites with WO₃ or CuO nanostructures to improve the photocatalytic performance of ZnO nanostructures. Characterization of the nanocomposites using scanning electron microscopy, x-ray diffraction, UV-vis spectrometry and photoluminescence revealed the morphologies and wide light absorption range of the materials. The highest current densities of WO₃/ZnO and CuO/ZnO nanocomposites were 1.28 mA cm^-2 and 2.49 mA cm^-2 at 1.23 V (versus a reversible hydrogen electrode) under AM 1.5 100 mW cm^-2, which are ~1.2- and 3.5-fold greater than those of bare ZnO nanostructures, respectively. The easy fabrication process suggests that nanocomposites with narrow bandgap materials, such as WO₃ and CuO, will improve the performance of electrochemical and optoelectrical devices such as dye-sensitized solar cells and biosensors.