Polydopamine-Derived Carbon Catalysts with Optimized Structure-Activity Design towards Electrochemical CO2 Reduction to CO

Electrochemical reduction of CO2 into chemical feedstocks has been regarded as an attractive way to reconstruct the carbon cycle. In this work, nitrogen-doped carbon was prepared by high temperature pyrolysis using polydopamine (PDA) microspheres as precursors. The effects of doped nitrogen units, surface hydrophilicity and pore structures of the N-Carbon catalysts on the CO2 reduction reaction (CO2RR) activities were systematically investigated. It was demonstrated that the competition between the hydrogen evolution reaction (HER) and the CO2RR under reduction potentials was modified by the nature of surface hydrophilicity/hydrophobicity and the doped nitrogen units. The CO2RR activities were further optimized via the pore structures regulation. Results showed that pore structure with size below 1 nm was favorable for CO2RR and the developed N-Carbon catalysts with optimized nitrogen units, hydrophilicity, and pore structure achieved a high CO2 to CO Faradaic efficiency of 95 % in the H-cell.