Thermal Oxidation and SILAR Method to Prepare CuO/CdS Composite Nanostructure and Its Enhanced Photocatalytic Properties

In this study, a series of CuO/CdS composites were synthesized by thermal oxidation and successive ionic layer adsorption and reaction (SILAR). The as-prepared CuO/CdS composites were investigated by x-ray diffraction (XRD), field emission high-resolution scanning electron microscopy (FESEM) and energy-dispersive spectrometry. Their photocatalytic activity was investigated by monitoring the degradation of methylene blue (MB) under ultraviolet and visible light irradiation. The XRD pattern indicated that the precursor was cubic-phase CuO and Cu₂O. FESEM results indicate that changes in annealing time and temperature have an effect on morphology, but the nanowire structures are preserved. The growth mechanism of the CuO nanowires is discussed in detail. Furthermore, the photocatalytic degradation rate of the MB, determined using an ultraviolet-visible spectrophotometer (UV-vis, UV-2600, Shimadzu), indicates that CdS can significantly improve the absorption of visible light from the sun.