Nitrogen-doped nanocarbon materials under electroreduction operating conditions and implications for electrocatalysis of CO2

We have used Kohn-Sham density functional theory with atomistic thermodynamics to identify various forms of N-doped graphene basal planes and nanoribbons that are thermodynamically relevant for CO2 electroreductions. Using our computational results, we derive phase diagrams for different nanocarbon structures, and we report which structures are suitable for hydrogen transfers to CO2 with low over potentials. With the incorporation of N atoms, standard reduction potentials resulting in hydrogenated surfaces become less negative, and this effectively opens pathways for hydrogen atom shuttling to CO2 with reversibly hydrogenating nanocarbon catalysts. Of all morphologies considered, N-doped zigzag nanocarbon edges are most favorable for energetically efficient CO2 electroreductions. (C) 2016 Elsevier Ltd. All rights reserved.