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Abstract A single device combining the functions of a CO₂electrolyzer and a formate fuel cell is a new option for carbon‐neutral energy storage but entails rapid, reversible and stable interconversion between CO₂and formate over a single catalyst electrode. We report a new catalyst with such functionalities based on a Pb–Pd alloy system that reversibly restructures its phase, composition, and morphology and thus alters its catalytic properties under controlled electrochemical conditions. Under cathodic conditions, the catalyst is relatively Pb‐rich and is active for CO₂‐to‐formate conversion over a wide potential range; under anodic conditions, it becomes relatively Pd‐rich and gains stable catalytic activity for formate‐to‐CO₂conversion. The bifunctional activity and superior durability of our Pb–Pd catalyst leads to the first proof‐of‐concept demonstration of an electrochemical cell that can switch between the CO₂electrolyzer/formate fuel cell modes and can stably operate for 12 days. 

Abstract Hybrid electrodes with improved O₂tolerance and capability of CO₂conversion into liquid products in the presence of O₂are 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 CO₂molecule and the basic amino group of aniline renders enhanced CO₂separation from O₂. Loaded with a cobalt phthalocyanine‐based cathode catalyst, the hybrid electrode achieves a CO Faradaic efficiency of 71 % with 10 % O₂in the CO₂feed gas. The electrode can still produce CO at an O₂/CO₂ratio as high as 9:1. Switching to a Sn‐based catalyst, for the first time O₂‐tolerant CO₂electroreduction to liquid products is realized, generating formate with nearly 100 % selectivity and a current density of 56.7 mA cm⁻²in the presence of 5 % O₂.