Enhancing Electrocatalytic CO₂-to-CO Conversion by Weakening CO Binding through Nitrogen Integration in the Metallic Fe Catalyst

Abstract

Metallic iron (Fe) typically demonstrates the unfavorable catalytic activity for the CO 2 reduction reaction (CO 2 RR), mainly attributed to the excessively strong binding of CO products on Fe sites. Toward this end, we employed an effective approach involving electronic structure modulation through nitrogen (N) integration to enhance the performance of the CO 2 RR. Here, an efficient catalyst has been developed, composed of N-doped metallic iron (Fe) nanoparticles encapsulated in a porous N-doped carbon framework. Notably, this Nintegrated Fe catalyst displays significantly enhanced performance in the electrocatalytic reduction of CO 2 , yielding the highest CO Faradaic efficiency of 97.5% with a current density of 6.68 mA cm −2 at −0.7 V versus the reversible hydrogen electrode. The theoretical calculations, combined with the in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy study, reveal that N integration modulates the electron density around Fe, resulting in the weakening of the binding strength between the Fe active sites and *CO intermediates, consequently promoting the desorption of CO and the overall CO 2 RR process.