Theoretical screening of the transition metal heteronuclear dimer anchored graphdiyne for electrocatalytic nitrogen reduction

Developing efficient electrocatalysts for nitrogen reduction reaction (NRR) is crucial to replace the both energy–intensive and environment–malignant Haber–Bosch process. Here using density functional theory calculations, we systematically studied the potential of the heteronuclear 3d transition metal dimers anchored graphdiyne monolayers (FeM@ and NiM@GDY, M = Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) as efficient NRR catalysts. Among all the studied double–atom catalysts (DACs), FeCo@ and NiCo@GDY are the most promising with excellent NRR catalytic activity, high ability to suppress the competing hydrogen evolution reaction (HER), and good stability. For both FeCo@ and NiCo@GDY, NRR prefers to the distal pathway with the calculated onset potentials of −0.44 and −0.36 V, respectively, which are comparable and even better than their homonuclear counterparts. Moreover, FeCo@ and NiCo@GDY have higher ability to suppress HER than Fe2@ and Co2@GDY, which may result from the modulated d state electronic structure due to the synergy effect of the heteronuclear atoms in the DACs. Our work not only suggests that FeCo@ and NiCo@GDY hold great promises as efficient, low–cost, and stable DACs for NRR, but also further provides a strategy, i.e. alloying the atomic metal catalysts, to improve the NRR catalytic activity and/or selectivity. © 2020 Science Press