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 Ebin < 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.