Efficient electroreduction of CO2 to CO on silver single-atom catalysts: Activity enhancement through coordinated modulation of polyaniline

The electrochemical reduction of CO2 to CO is considered to be one of the most mature routes that could be commercialized for efficient utilization of large amount of CO2. Silver (Ag) has shown high selectivity towards CO but usually requires high reduction potential. Herein, a novel Ag single atom-polyaniline (PANI) is constructed directly on gas diffusion electrode (GDE). The amino group with strong electron-donating ability in PANI can effectively promote the adsorption and activation of CO2. In addition, the adsorption of *COOH is significantly enhanced on N-coordinated Ag. The proposed catalyst electrode shows an outstanding performance with the Faraday efficiency of CO close to 100% at -0.75 V (vs. RHE), the energy efficiency is 12.8% and the output of CO is 108.7 mL cm-2 h-1, which exceeds most state-in-art Ag-based catalysts, highlighting the importance for the rational design and controllable fabrication of active sites and their favorable chemical environments.