Self-Selective Silver Electrocatalyst for Efficient Carbon Dioxide Electroreduction to Carbon Monoxide

Given the economic potential of electrocatalytic carbon dioxide (CO₂) reduction reaction (eCO₂RR) to carbon monoxide (CO), developing simple and scalable methods to fabricate electrodes that offer high CO selectivity at high current densities remains an urgent imperative. Herein, cellulose acetate-derived carbon fibers (CACFs) were first fabricated via electrospinning followed by high-temperature carbonization. These CACFs served as substrates for the construction of self-selective Ag electrocatalysts (SELF-ECAT-Ag/CACFs) through an electrodeposition strategy under a CO₂ atmosphere. This electrode reached a maximum Faradaic efficiency of 98.8% for CO at -1.34 V versus SHE. Meanwhile, the Faradaic efficiency for CO remained above 80% over a wide applied potential window from -1.14 to -1.54 V versus SHE, and the maximum CO partial current density achieved 157.3 mA cm^-2 at -1.54 V versus SHE. The excellent catalytic activity was closely associated with the unique dendritic structure of SELF-ECAT-Ag/CACFs electrodes, which could expose more active sites and enhance CO₂ adsorption capacity. Meanwhile, the SELF-ECAT-Ag/CACFs electrode and the 1-butyl-3-methylimidazolium hexafluorophosphate-based electrolyte collectively promoted CO production. Furthermore, density functional theory calculations revealed that the abundant edge structures in the electrocatalyst could facilitate the *COOH formation and adsorption, thereby contributing to the eCO₂RR to CO.