n–n Heterojunction TiO ₂ /FeOCl Composites for Highly Efficient Visible‐Light Photocatalytic Degradation of Organic Dye Wastewater

ABSTRACT The advanced treatment of dye wastewater is a challenging problem due to its toxicity and high stability. However, the large band gap of traditional photo‐catalyst TiO 2 leads to weak absorption of visible light, restricting the application of photo‐oxidation technology. Here, the n–n type TiO 2 /FeOCl interface hetero‐junction catalyst was constructed by a facile hydrothermal method. The visible light response range of the material was broadened, leveraging the fact that leveraging the Fermi level of FeOCl was higher than that of TiO 2 . At a mass ratio of 7:3(TiO 2 /FeOCl), the composite exhibited the optimal photocatalytic performance. The degradation efficiency of Rhodamine B (RhB) can reach 70 % within 150 min, and the rate constant is about 2.3 times that of pure TiO 2 and FeOCl. Electrochemical tests demonstrated that the hetero‐junction significantly enhanced the separation and transfer of photo‐generated charges, and the catalyst still maintained high stability after five cycles. This study presents a novel approach for constructing efficient and stable photocatalysts for wastewater treatment.