Application of Co3O4 in Photoelectrocatalytic Treatment of Wastewater Polluted with Organic Compounds: A Review

The negative effects of refractory organic substances in water on the environment and life have aroused worldwide attention. The efficiency of using photoelectrocatalysis (PEC) to degrade refractory organic pollutants depends to a large extent on the properties of the photoanode semiconductor. Therefore, the selection of a satisfactory photoanode semiconductor material to promote the production of intermediate reactive species (hydroxyl radicals and superoxide radicals) has become a key issue in improving the efficiency of PEC. Among the available catalysts, transition metal oxides have received a lot of attention in recent years due to their low price and significant advantages. Due to its outstanding photoelectrocatalytic properties, Co3O4 has emerged as a candidate to serve as a photoelectrocatalyst specifically for the oxidation of water with oxygen in these materials. This paper summarizes in detail the recent advances in Co3O4 materials for PEC, both pure Co3O4 and Co3O4-based composites. In addition, this review discusses the impact of strategies on the performance of photoelectrocatalysts, such as synthesis methods, crystal surface structures, and composites. Finally, this review concludes with a presentation of the challenges and workable solutions for Co3O4-based materials in PEC, along with a discussion of their potential for future research.