Complex ZnO/ZnS nanocable and nanotube arrays with high performance photocatalytic activity

Abstract

The complex ZnO/ZnS nanocable and nanotube arrays have been grown on the silicon or glass substrates with ZnO nanowire arrays by an aqueous chemical growth method at the low reaction temperature. The concentration of ZnS precursor and reaction time can be used to control the different sizes and shell thicknesses of complex ZnO/ZnS nanocable and nanotube arrays. The complex ZnO/ZnS nanocable and nanotube arrays exhibit very prominent blue emission and week UV emission from ZnS defect and ZnO band gap in the cathodoluminescence spectrum, respectively. The photocatalytic activity of the different complex ZnO/ZnS nanocable and nanotube arrays were evaluated in the photocatalytic degradation of methylene blue under 10 W UV light irradiation. The complex ZnO/ZnS nanocable and nanotube arrays revealed much higher photodegradation efficiency than ZnO nanowire arrays. This result is attributed to increase the separation of photogenerated electron–hole pairs on the surface of ZnO/ZnS nanocable and the surface-to-volume ratio on the ZnS nanotube. The photocatalytic mechanism under UV light irradiation was proposed. Furthermore, the reusability test can demonstrated that the complex ZnO/ZnS nanocable and nanotube arrays still maintained high photocatalytic activity over ten cycles. The complex ZnO/ZnS nanocable and nanotube arrays provide a facile, low cost, high surface-to-volume ratio, high photocatalytic efficiency, and high reusability, which shall be also promising in many related areas, such as solar energy conversion, water splitting, and energy storage.