Polyacrylamide-Mediated Silver Nanoparticles for Selectively Enhancing Electroreduction of CO2 towards CO in Water.

Abstract

Conversion of the greenhouse gas CO2 to value-added products is an important challenge for sustainable energy research. Here, a durably nanohybrid composed of Ag nanoparticles and polyacrylamide was constructed for the selectively electroreduction of CO2 to CO. The nanohybrid exhibited an outstanding CO faradaic efficiency of 97.2±0.2 % at -0.89 VRHE (vs. the reversible hydrogen electrode) with a desirable CO partial current density of -22.0±2.3 mA cm-2 and maintained the CO faradaic efficiency above 95 % over a wide potential range (-0.79 to -1.09 VRHE ), showing excellent stability during a 48 h prolonged electrolysis. The origins of selective enhancement of CO2 reduction over the nanohybrid stemmed from the activation of CO2 via hydrogen bond and the low basicity of the amide. DFT calculations implied that the synergy of Ag nanoparticles and amide could better stabilize the key intermediate (*COOH) and effectively lower the overpotential of CO2 reduction. These results establish the synergistic effects of organic/inorganic hybrid as a complementary method for tuning selectivity in CO2 -to-fuels catalysis.