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 Fe-2@ and Co-2@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. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

The study found that FeCo@ and NiCo@GDY are efficient NRR catalysts with excellent catalytic activity, high ability to suppress HER, and good stability. These bimetallic catalysts improve the catalytic activity and selectivity of NRR through alloying.