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

Hybrid electrodes with improved O₂ tolerance and capability of CO₂ conversion into liquid products in the presence of O₂ 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 CO₂ molecule and the basic amino group of aniline renders enhanced CO₂ separation from O₂ . Loaded with a cobalt phthalocyanine-based cathode catalyst, the hybrid electrode achieves a CO Faradaic efficiency of 71 % with 10 % O₂ in the CO₂ feed gas. The electrode can still produce CO at an O₂ /CO₂ ratio as high as 9:1. Switching to a Sn-based catalyst, for the first time O₂ -tolerant CO₂ 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 % O₂ .