Tuning Gold Nanoparticles with Chelating Ligands for Highly Efficient Electrocatalytic CO2 Reduction

Capped chelating organic molecules are presented as a design principle for tuning heterogeneous nanoparticles for electrochemical catalysis. Gold nanoparticles (AuNPs) functionalized with a chelating tetradentate porphyrin ligand show a 110-fold enhancement compared to the oleylamine-coated AuNP in current density for electrochemical reduction of CO2 to CO in water at an overpotential of 340 mV with Faradaic efficiencies (FEs) of 93%. These catalysts also show excellent stability without deactivation (<5% productivity loss) within 72 hours of electrolysis. DFT calculation results further confirm the chelation effect in stabilizing molecule/NP interface and tailoring catalytic activity. This general approach is thus anticipated to be complementary to current NP catalyst design approaches.