A Cu-Modified Photocatalyst Composite: Synthesis, Characterization and Photocatalysis

To obtain highly efficient photocatalysts, we successfully prepared the GO/ZnO/CdS/Cu 2 S composite that possesses superior photocatalytic degradation performance via a three-step solvothermal process. A series of characterization techniques were used to verify the composition and performance of prepared samples, such as X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscopy (SEM), Raman spectra, photoluminescence (PL) spectroscopy and so on. SEM reveals that copper ions are supported on the surface of CdS to form active sites for photocatalysis. Under the irradiation of ultraviolet (UV) and visible light, GO/ZnO/CdS/Cu 2 S photocatalyst exhibited relatively excellent photocatalytic degradation efficiency of methylene blue (MB), with 100% (80 min) and 95% (30 min), respectively. Compared with pure ZnO ( k = 7 . 1 4 × 1 0 − 4 ) under the illumination of UV light, the kinetic constant of GO/ZnO/CdS/Cu 2 S catalyst is up to 8 . 1 3 × 1 0 − 2 , and as for visible light illumination, up to 9 . 8 7 × 1 0 − 2 , showing relatively excellent visible-light-induced photocatalytic activity. Besides, under UV and visible light, after three cycles of photodegradation, GO/ZnO/CdS/Cu 2 S still maintains the degradation efficiency of 78.3% and 74.8%, respectively, indicating that it has good stability. This work might inspire a new perspective that introduces the surface reaction sites (Cu 2 S) in the design of other graphene oxide/mental oxide-based heterojunctions for environmental purification.