Single-atom catalyst of TM@D-silicene—an effective way to reduce N2 into ammonia

Abstract

Nowadays, the electrocatalytic nitrogen reduction reaction (NRR) still faces great challenges. It's significant to design the electrocatalysts with excellent activity and high selectivity. Herein, the 28 single atom catalysts of transition metal atoms anchored on defective silicene (TM@D-silicene) are designed for electrocatalytic ammonia synthesis under ambient conditions. Two independent screening schemes are proposed to screen the potential SAC candidate. The criteria of E_bin < 0 eV, ΔG_*N2< −0.1 eV, ΔG_*H > ΔG_*N2, and the lowest ΔG_*NNH in scheme I, as well as ΔG_*N2< −0.1 eV, smaller G_*NNH and larger G_*NH2 in scheme II are utilized in the screening procedure. Finally, Cr@D-silicene is picked out since it performs well in the aspects of N₂ adsorption, selectivity and catalytic activity of NRR. Moreover, the electronic properties are systematically investigated to clarify why the Cr@D-silicene is qualified for NRR from the perspective of the strong interaction between N₂ and Cr, the continuous activation of the N₂ molecule, charge transfer and distribution. This work provides a new idea for electrocatalytic ammonia synthesis by using single-atom catalysts.