A Review on Cu2O-Based Composites in Photocatalysis: Synthesis, Modification, and Applications

Photocatalysis technology has the advantages of being green, clean, and environmentally friendly, and has been widely used in CO2 reduction, hydrolytic hydrogen production, and the degradation of pollutants in water. Cu2O has the advantages of abundant reserves, a low cost, and environmental friendliness. Based on the narrow bandgap and strong visible light absorption ability of Cu2O, Cu2O-based composite materials show infinite development potential in photocatalysis. However, in practical large-scale applications, Cu2O-based composites still pose some urgent problems that need to be solved, such as the high composite rate of photogenerated carriers, and poor photocatalytic activity. This paper introduces a series of Cu2O-based composites, based on recent reports, including pure Cu2O and Cu2O hybrid materials. The modification strategies of photocatalysts, critical physical and chemical parameters of photocatalytic reactions, and the mechanism for the synergistic improvement of photocatalytic performance are investigated and explored. In addition, the application and photocatalytic performance of Cu2O-based photocatalysts in CO2 photoreduction, hydrogen production, and water pollution treatment are discussed and evaluated. Finally, the current challenges and development prospects are pointed out, to provide guidance in applying Cu2O-based catalysts in renewable energy utilization and environmental protection.