Nano-polyaniline enables highly efficient electrocatalytic reduction of CO2 to methanol in supporting electrolyte-free media and the detection of free-radical signals

Metals and metal oxides are widely used as catalysts for the electrochemical reduction of CO2. Here, we report a low-cost catalyst based on nano-polyaniline polymerized on graphite for the electrochemical reduction of CO2 in CO2-saturated water free of supporting electrolytes. The nano-polyaniline electrode in this solution shows low resistance and low charge-transfer impedance (R-ct), which leads to a rather high reduction current density (-16.8 mA cm(-2)) and low overpotential (-0.44 V vs. Ag/AgCl). This solution is environment-friendly and mimics that in photosynthesis. The free radical signal of CO2 was successfully detected during the reduction process. The H-1 NMR result demonstrates that the only product formed was methanol.

Automated summary

A low-cost catalyst based on nano-polyaniline polymerized on graphite was reported for the electrochemical reduction of CO2 in CO2-saturated water free of supporting electrolytes. The nano-polyaniline electrode in this solution showed low resistance and low charge-transfer impedance, resulting in a high reduction current density and low overpotential. The only product formed during the reduction process was methanol, detected through H-1 NMR.