Despite the high selectivity and la

Despite the high selectivity and large current density, the disadvantages for future commercial application of GDEs, such as the short contact time between CO2 and electrocatalyst, the poor stability due to impurity deposition on the electrocatalyst, the complexity in system setup, and the penetration of electrolyte (liquid) into the gas diffusion electrode leading to flooding and so on23, 24, are very serious. In addition, the electroreduction of CO2 in gas phase is also an efficient approach to alleviate the limitations of low solubility of CO2 in aqueous solution, which can also remove the possibility of electrolyte flooding suffered in GDE (gas diffusion electrode) due to the elimination of catholyte. Currently, three types of membrane electrode assemblies (MEAs) are used in CO2 gas-phase reduction25: cation exchange membranes (CEMs), anion exchange membranes (AEMs), and bipolar polymer membranes (BPM). All of them consist of a cathode and anode separated by an ion-exchange membrane, and the electrocatalyst is directly pressed against the membrane in a zero-gap configuration