Converting CO 2 into Value-Added Products by Cu 2 O-Based Catalysts: From Photocatalysis, Electrocatalysis to Photoelectrocatalysis.

Converting CO 2 into value-added products by photocatalysis, electrocatalysis, and photoelectrocatalysis is a promising method to alleviate the global environmental problems and energy crisis. Among the semiconductor materials applied in CO 2 catalytic reduction, Cu 2 O has the advantages of abundant reserves, low price and environmental friendliness. Moreover, Cu 2 O has unique adsorption and activation properties for CO 2 , which is conducive to the generation of C 2+ products through CC coupling. This review introduces the basic principles of CO 2 reduction and summarizes the pathways for the generation of C 1 , C 2 , and C 2+ products. The factors affecting CO 2 reduction performance are further discussed from the perspective of the reaction environment, medium, and novel reactor design. Then, the properties of Cu 2 O-based catalysts in CO 2 reduction are summarized and several optimization strategies to enhance their stability and redox capacity are discussed. Subsequently, the application of Cu 2 O-based catalysts in photocatalytic, electrocatalytic, and photoelectrocatalytic CO 2 reduction is described. Finally, the opportunities, challenges and several research directions of Cu 2 O-based catalysts in the field of CO 2 catalytic reduction are presented, which is guidance for its wide application in the energy and environmental fields is provided.