A Review on Photocatalytic and Electrocatalytic Reduction of CO2 into C2+ Products: Recent Advances and Future Perspectives

The collection of CO2 and its subsequent transformation into valuable compounds have drawn increased global attention in recent decades. It is commonly recognized that the final product of every combustion process, whether biological or chemical, is CO2, a fully oxidized, thermodynamically stable, and chemically inert molecule. Owing to the chemical inertness of CO2, it adsorbs and reacts slowly on catalyst surfaces and has a poor capacity to form chains. It also makes it simpler to produce C1 compounds and more challenging to produce products that are higher than C2. Many scientific research teams have focused on CO2 hydrogenation to prepare C1 chemical feedstocks (such as CH4, CH3OH, CO, HCOOH, etc.), and significant progress has been made. However, from the point of view of economic value, the synthesis of higher-order multicarbon products (C2+) is preferable to that of C1 products due to their higher energy density and broader applicability. Considering the rapid development of catalytic reduction of CO2 into C2+ products, it is necessary to have a comprehensive understanding and timely, appropriate summary of these technologies. Therefore, this review aims to present a comprehensive and critical review of the research status and development trend of catalytic reduction of CO2 into C2+ products.