Visible-light induced photocatalytic removal of methylene blue dye by copper oxide decorated zinc oxide nanorods

The establishment of rod-shaped visible light heterojunction ZnO/CuO composites for potential redox ability presents a potential application prospect in the development of efficient photocatalysts for environmental purification. Herein, the CuO-decorated ZnO nanorods composites with preeminent retrievability were obtained by the simple hydrothermal method. The physicochemical properties of the ZnO, CuO and its composites were explored through systematic characterizations. X-ray diffraction (XRD) results show that the ZnO belongs to the wurtzite structure and CuO belongs to the monoclinic crystal structure. The size, shape and elemental composition of the ZnO/CuO composites were confirmed by high-resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS) analysis. The average length of the nanorods is around 420 to 430 nm and the diameter is around 24–30 nm, respectively. The synthesized CuO/ZnO composites were used as a photocatalyst for the degradation of methylene blue (MB) dye under UV–visible light irradiation (UV–Vis). Particularly, ZnO/CuO (10%) composites achieved 98.5% degradation within 150 min, thus evidence suggesting that ZnO/CuO (10%) composites exhibited the best catalytic activity at optimum photocatalytic conditions. The composite materials contain a synergistic effect/factor, which is positive interaction between the CuO and ZnO to improve the photocatalytic activity. In addition, ZnO/CuO (10%) composites demonstrated good reusability and stability while retaining their high photocatalytic activity. It was estimated that this study could create a new opportunity to fabricate easily recoverable and eco-friendly photocatalysts with nanosized heterojunction for efficient removal of organic dyes, antibiotic pollutants and pesticides etc under visible light irradiation.