Upcycling solid wastes into functional supports for TiO2 and its high prospect in photocatalytic elimination of pollutants: A critical review

Nowadays, environmental pollution has severely restricted the development of human society. Among all pollution control technologies, photocatalytic degradation is considered to be a sustainable and cost-effective one. At present, TiO2 is the most common photocatalyst, exhibiting merits of excellent photocatalytic degradation performance, high stability, and low cost etc. However, some demerits of TiO2, such as aggregation of nano-particles, low recovery, poor visible light responsive ability, et al. still hamper its large-scale application. In order to cope with these issues, various materials have been employed as TiO2 supports. Based on the sustainable concept of "treating pollution with wastes", immobilization of TiO2 on cheap and stable solid wastes has been proposed, which is a promising route to promote the application of TiO2 and reutilize solid waste in a value-added way. Therefore, we reviewed the research status of solid waste supported TiO2 composite materials in photocatalytic degradation of pollutants, with focus on the fabrication method, adsorption property, photocatalytic degradation efficiency, recycling performance, chemical stability. We also provide future research directions for solid waste supported TiO2 composites.