Acid–Base Interaction Enhancing Oxygen Tolerance in Electrocatalytic Carbon Dioxide Reduction

Hybrid electrodes with improved O 2 tolerance and capability of CO 2 conversion into liquid products in the presence of O 2 are presented. Aniline molecules are introduced into the pore structure of a polymer of intrinsic microporosity to expand its gas separation functionality beyond pure physical sieving. The chemical interaction between the acidic CO 2 molecule and the basic amino group of aniline renders enhanced CO 2 separation from O 2 . Loaded with a cobalt phthalocyanine‐based cathode catalyst, the hybrid electrode achieves a CO Faradaic efficiency of 71 % with 10 % O 2 in the CO 2 feed gas. The electrode can still produce CO at an O 2 /CO 2 ratio as high as 9:1. Switching to a Sn‐based catalyst, for the first time O 2 ‐tolerant CO 2 electroreduction to liquid products is realized, generating formate with nearly 100 % selectivity and a current density of 56.7 mA cm −2 in the presence of 5 % O 2 .