Boosting hydrogen evolution activity of transition meta-nitrogen embedded graphene through introducing secondary transition metal

Exploring highly efficient catalysts for the electrochemical hydrogen evolution reaction (HER) is highly demanded in the sustainable production of hydrogen. Herein, we report a feasible strategy to create the atomic-scale dual sites in functional graphene via introducing the secondary TM dopant into the TMN 4 pre-embedded graphene, termed as TM a N 4 /TM b for simplification. According to the free energy analysis, we identify two homogenous combinations of Mn a N 4 /Mn b and Fe a N 4 /Fe b wherein the free energies of hydrogen adsorption are 0.08 and 0.04 eV for Mn a N 4 /Mn b meanwhile 0.00 and -0.01 eV for Fe a N 4 /Fe b , respectively, indicating the significant improvement in comparison with the separated components. Furthermore, the reaction barriers of H 2 O splitting are 1.62 and 1.08 for Mn a N 4 /Mn b and Fe a N 4 /Fe b , revealing the relative better proton supply of the latter under alkaline electrolyte. Furthermore, the binding energies are -6.00 and -5.71 eV for Mn a N 4 /Mn b meanwhile -6.63 and -5.70 eV for Fe a N 4 /Fe b , respectively, which substantially exceed the corresponding cohesive energies and thereby avoid the atom clustering. Therefore, the interatomic bonding of dual active sites as a chemical facilitator paves a novel route for the design of efficient catalysts at the atomic scale.