Mechanistic insight into electroreduction of carbon dioxide on FeNx (x = 0 - 4) embedded graphene
Searching for non–precious, active and stable catalysts for CO2 electrochemical reduction (CO2ER) has attracted extensive attention, while the high overpotential and low efficiency hinder the widespread commercial applications on a large scale. In this work, density function theory (DFT) calculations were conducted on the CO2ER process by FeNx embedded graphene (i.e., FeNx–gra, x = 0 – 4). The results reveal that Fe atom strongly interacts with the unsaturated N atoms of the substrate and acts as the active site. Due to the small limiting potential of –0.78 V and activation barrier (1.56 eV), FeN3–gra exhibits highest catalytic activity towards CO2 reduction. The products of CO2ER catalyzed by FeN3–gra are CH4 and CH3OH, in which CO* → HCO* is the potential–determining step. It is expected that FeN3–gra would be a promising catalyst for CO2ER.