A New Approach for the Synthesis of Heterostructured TiO2/ZnS0. 77Se0. 23 Composites with Enhanced Photocatalytic Activity: A Combination of Solid-State and Sol–Gel Methods

Novel heterostructured TiO2/ZnS0.77Se0.23 catalysts were synthesized by a combined solid-state and sol–gel method. They were characterized by several techniques, including powder X-ray diffraction, scanning electron microscopy, UV-vis diffuse reflectance spectroscopy, and Raman spectroscopy. The results of photocatalytic degradation of methylene blue (MB) over the as-prepared materials show that the photocatalytic efficiency is closely related to the composition of the materials. The 30%TiO2/ZnS0.77Se0.23 (3TZSS) catalyst exhibits the best efficacy under simulated solar or visible light irradiation. Furthermore, mechanisms for photodegradation and photocatalytic enhancement are put forward. Recycle experiments show that the 3TZSS catalyst is stable for the degradation of MB. The present work opens up an avenue to the design and fabrication of stable and high-efficiecy catalysts for the degradation of organic pollutants.