Insights into the adsorption/desorption of CO2 and CO on single-atom Fe-nitrogen-graphene catalyst under electrochemical environment

•AIMD simulations were employed under explicit aqueous model and considered electrode potential explicitly.•Electrode potential can be linearly tuned by adding cations or anions into the solution.•Reductive electrode potential promotes CO2 adsorption, whereas the impact of electrode potential is much less significant on CO adsorption.•CO desorption might be the rate determining step rather than the activation of CO2.•The angle of O-C-O in CO2 and bond length of C-O in CO change linearly with their negative charge.