Abstract
Selective electrochemical reduction of CO2 into energy-dense organic compounds is a promising strategy for using CO2 as a carbon source. Herein, we investigate a series of iron-based catalysts synthesized by pyrolysis of Fe-, N- and C- containing precursors for the electroreduction of CO2 to CO in aqueous conditions and demonstrate that the selectivi-ty of these materials for CO2 reduction over proton reduction is governed by the ratio of isolated FeN4 sites vs. Fe-based nanoparticles. This ratio can be synthetically tuned to generate electrocatalysts producing controlled CO/H2 ratios. It notably allows preparing materials containing only FeN4 sites, which are able to selectively reduce CO2 to CO in aqueous solution with Faradaic yields over 90% and at low overpotential.