Enhancing CO2 electroreduction with Au/pyridine/carbon nanotubes hybrid structures.

Selective electrochemical reduction of CO2 using renewable electricity has received considerable attention because of the potential to convert a harmful greenhouse gas to a useful chemical. In this report, we construct a high-performance electrocatalyst based on metal nanoparticles/organic molecule hybrid materials for CO2 reduction. On the nanoscale, Au nanoparticles are uniformly anchored on carbon nanotubes to afford substantially increased current density, improved selectivity for CO, and enhanced stability. On the molecular level, the catalytic performance is further enhanced by introducing axial pyridine groups to the surface of carbon nanotubes. The resulting hybrid catalyst exhibits around 93% Faradaic efficiency for CO production in a wide potential range (-0.58 V～-0.98 V) and a high mass activity of 251 A g-1Au at -0.98 V in aqueous solution at near-neutral pH and strong stability with continuous electrolysis for 10 h at -0.58 V. DFT calculations enlighten that the synergy between Au and axial pyridine could dramatically stabilize the key intermediate (*COOH) formed in the rate-limiting step of CO2 reduction, which effectively lowers the overpotential.