Understanding double perovskite oxides capabilities to improve photocatalytic contaminants degradation performances in water treatment processes: A review

Clean energy and environmental technologies are essential for a sustainable future. Photocatalysts are at the core of these technologies, increasing the efficiency of key chemical reactions and improving their selectivity. Metal oxides like perovskite oxides are long recognized as active photocatalysts of rather simple ionic arrangements. Double perovskites are alternatives to single perovskites, which are known as cation ordered perovskites. Double perovskite oxides such as A2B'B“O6 are emerging compounds with various optoelectronic properties that are suitable for optics, photonics, electronics, and catalysis applications. A, B', and B” are cations with varying degrees of chemical flexibility, leading to multiple combinations, which make them excellent candidates as advanced materials. Herein, we comprehensively screened stable A2B'B“O6 double perovskite metal oxides arranged based on Sr, La, K, Gd, Ba, Na, Ca, Dy, Tb, Sm, Eu, and Bi cations ordered at A sites that have been used in photocatalytic pollutant degradation and water treatment processes. Also, we examined recent developments of double perovskites oxides as photocatalysts through discussion on how their chemistries could be tailored to improve their performances. Also, photocatalytic process was explained along with its characteristics, milestones, mechanisms, modes of operation, and double perovskites materials used in this field indicating unique photocatalytic properties.