  Electrochemical reduction of CO2 to CO is a promising strategy. However,
achieving high Faradaic efficiency with high current density using ILs
electrolyte remains a challenge. In this study, the IL N octyltrimethyl 1,2,4
triazole ammonium shows outstanding performance for electrochemical reduction
of CO2 to CO on the commercial Ag electrode, and the current density can be up
to 50.8 mA cm-2 with a Faradaic efficiency of 90.6%. The current density of CO
is much higher than those reported in the ILs electrolyte. In addition, the
density functional theory calculation further proved that IL interacts with CO2
to form IL CO2 complex which played a key role in reducing the activation
energy of CO2. According to the molecular orbital theory, the electrons
obtained from ILs was filled in the anti bonding orbit of the CO2, resulting in
reducing the C=O bond energy. This work provides a new strategy to design novel
ILs for high efficiency electrochemical reduction of CO2 to CO.
