Metal halide perovskite-based photocatalysts for organic pollutants degradation: Advances, challenges, and future directions

Organic pollutants such as fertilizers, oils, greases, pharmaceuticals, and organic dyes which endanger natural water resources and treated water waste are highly toxic and perilous; therefore, removing such matters prior to drainage into the environment is imperative. Designing technologies for degrading these contaminants have created a challenge to scientists and researchers. A variety of techniques have been utilized to degrade these organic pollutants. Photocatalysis is a promising technique due to its unique physicochemical, optical and electrical properties. In the current review, Metal Halide Perovskite-based photocatalysts employed to drive various reduction and oxidation reactions under light irradiation with suitable wavelengths were highlighted. The photocatalytic fundamentals of MHP-based photocatalysts including the basic mechanism of heterogeneous photocatalysis along with their synthesis methods have been summarized. The multifunctional properties of MHP-based photocatalysts in the degradation of organic pollutants have been emphasized through the presentation of several related recent studies. However, there is still no consensus among researchers about the most efficient composites as many challenges exist. While previously published papers on metal halide perovskite photocatalysts provided a general discussion on the various applications of MHPs in several aspects, the current review specifies and details the application MHPs on water treatment. Further, the effect of the different MHP synthesis methods on the removal of organic contaminants from water was addressed. Besides, this review enumerates the major obstacles that impede the wide application of MHP photocatalysis, and aims at suggesting some solutions to be accounted for in future research.