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

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, Delta G(*N2)< -0.1 eV, Delta G(*H) > Delta G(*N2), and the lowest Delta G(*NNH) in scheme I, as well as Delta G(*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 N-2 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 N-2 and Cr, the continuous activation of the N-2 molecule, charge transfer and distribution. This work provides a new idea for electrocatalytic ammonia synthesis by using single-atom catalysts.

Automated summary

In this study, single-atom catalysts consisting of transition metal atoms anchored on defective silicene were designed for electrocatalytic ammonia synthesis. Among the 28 catalysts tested, Cr@D-silicene exhibited excellent performance in N-2 adsorption, selectivity, and catalytic activity of nitrogen reduction reaction (NRR). The electronic properties of Cr@D-silicene were investigated to understand why it is qualified for NRR in terms of strong interaction between N-2 and Cr, continuous activation of N-2 molecule, charge transfer, and distribution. This work suggests a new approach for electrocatalytic ammonia synthesis using single-atom catalysts.