Efficient molten salt CO2 capture and selective electrochemical transformation processes toward carbon neutrality: advances, challenges, and prospects

Atmospheric carbon dioxide (CO2) concentration has reached record levels due to excessive anthropogenic CO2 emissions from massive industrial productions. Renewable-energy-driven CO2 electroreduction is an effective method of directly converting CO2 into various value-added chemicals or materials without subsequent geological disposal treatment. Owing to their promising thermal stability, wide electrochemical window, tunable oxo-basicity, and nontoxic nature, molten salt electrolytes endow intrinsic advantages, such as fast CO2 absorption and selective electrochemical transformation, among different electrolyte species, wherein advanced carbon materials, CO, and hydrocarbons can be generated at relatively high current densities. Herein, we review the recent advances in molten salt CO2 capture and electrochemical transformation (MSCC-ET) technologies, including reaction mechanisms, CO2 absorption kinetics, electrode reaction kinetics, and product selectivity. This review highlights feasible strategies for regulating nanostructures, carbon product crystallinity, energy efficiency, overall CO2 conversion efficiency, and MSCC-ET adaptability toward practical flue gases. Moreover, suitable cost-effective inert anode candidates for the oxygen evolution reaction are discussed.