UV and Visible Light Induced Photocatalytic Degradation on p–n Cu ₂ O/ZnO Nanowires Decorated with Au–Pd Alloy Nanoparticles

Chemical solutions are applied to synthesize Au–Pd alloy nanoparticles (NPs) and ZnO/Cu ₂ O core–shell nanowires (NWs) on ITO/glass substrates by the photochemical, electrochemistry, and hydrothermal methods. The Cu ₂ O cubic structures and ZnO hexagonal wurtzite structures are verified as being polycrystalline and single crystalline, respectively, by X-ray diffraction and high-resolution transmission electron microscopy (HR-TEM). The p-Cu ₂ O/n-ZnO NWs samples exhibit rectification properties that confirm the p–n heterojunction interface. The diameter range of the Au–Pd alloy NPs is around 2–15 nm and the Au/Pd ratio is 27:28, according to HR-TEM and X-ray photoelectron spectroscopy. The p-Cu ₂ O/n-ZnO core–shell NWs feature higher UV photocatalytic degradation of methylene blue than do the ZnO NWs. Deposited Au, Pd, Au–Pd alloy NPs on the p-Cu ₂ O/n-ZnO core–shell NWs improve the photocatalytic degradation efficiency under UV and blue light. The Au–Pd alloy NPs/p-Cu ₂ O/n-ZnO core–shell NWs offer the best photocatalytic properties under UV- and blue-light-emitting diode (LED) illumination.