Progress in capture and electrochemical conversion of CO₂ into high value-added carbon materials by molten salts

With the increasing emission of CO2，the harm to the environment is gradually increasing. Reducing CO2 emissions and reducing the concentration of CO2 in the atmosphere is a hot topic of current research. CO2 is not only a greenhouse gas but also a rich and cheap carbon resource. The green and efficient conversion of CO2 into high-value-added carbon and the realization of CO2 resource utilization can help solve environmental problems and bring economic benefits. Carbon dioxide has good chemical stability and requires a significant amount of energy to decompose. Therefore，it is extremely challenging to use CO2 to produce high value-added carbon. However，oxychloride-containing molten salts and molten carbonates can effectively absorb CO2 to form carbonate ions，and carbon products can be obtained by electrochemical reduction of carbonate ions. In this review，the CO2 capture and electrochemical reduction of CO2 by molten salt are analyzed and summarized，and the effects of molten salt electrolyte system，electrode materials，and electrolysis temperature on electrochemical reduction of CO2 are expounded，the preparation of carbon nanotubes，carbon nanospheres，graphene，and other high value-added carbon by molten salt electrolysis is summarized and prospected.