Theoretical screening of highly efficient single-atom catalysts for nitrogen reduction based on a defective C3N monolayer

Abstract

Conversion of N2 to NH3 through electrochemical technology is one of the most attractive and promising alternatives to the traditional Haber-Bosch method. However, exploring the promising electrocatalysts with high stability, activity and selectivity for nitrogen reduction reaction (NRR) is still an important and long-standing challenge to accelerate the green production of NH3. Herein, through the first-principles high-throughput screening, we systematically investigated the potentiality of single transition metal (TM) anchored on defective C3N monolayer as TM-VCC candidates for N2 fixation. We carried out a comprehensive screening and systematical evaluation for stability, catalytic activity and selectivity toward NRR on TM-VCC candidates. Our results reveal that, among 26 candidates, Mn-VCC can significantly suppress HER and exhibit the outstanding NRR activity, with the most favorable limiting potential of −0.75 V through the distal pathway, which is better than the currently stepped catalyst Ru (0001). More impressively, such a satisfactory NH3 conversion is primarily ascribed to the strong back-donation interactions between d-electrons of Mn atom and the anti-orbitals of N2 molecule, as well as efficient charge transfer of electrochemical process. Our findings not only broaden the development prospect of SACs for N2 reduction but also pave a way for rational design and rapid screening of highly active C3N-based catalysts for NRR.