A review of electroreduction of CO2 to C1 products: Catalysts design, characterizations and performance evaluation

The large-scale use of fossil fuels leads to the rising concentration of CO2 in the atmosphere, which leads to serious environmental problem. In order to alleviate this problem, it is an effective way to convert CO2 to C1 (such as CO, CH4, CH3OH, formic acid and formate) as high value-added products, so as to make full use of carbon resources. Electrocatalytic CO2 reduction (CO2RR) is the use of renewable energy to reduce CO2 to valuable C1 products by using CO2 and H2O as raw materials. It has the advantages of low energy consumption, mild reaction conditions and no pollution, which has attracted wide attention in recent years. In this review, we firstly describe the basic principle, performance evaluation parameters and reaction devices of CO2RR, summarize the preparation methods of working electrodes, enumerate the types and application scenarios of commonly used electrolytes, as well as electrochemical test parameters and common product analysis methods. Then, we systematically summarize the research progress of CO2 electroreduction catalysts, including the application of single-atom catalysts, dual-atom catalysts and nano-porous metal catalysts in CO2RR, overview the design, preparation and characterization methods of CO2 electroreduction catalysts, and the structure and synthesis methods of various catalysts in detail. Finally, the C1 products generated by CO2RR, such as CO, CH4, CH3OH, formic acid and formate, are discussed, and the effects of catalysts with different structures on the products selectivity are analyzed.