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.