Efficient nitric oxide reduction to ammonia on a metal-free electrocatalyst

Abstract

NH₃ synthesis and NO removal are two of the most attractive and challenging processes in electrochemistry. Current research efforts mainly focus on them separately, while the direct electrochemical reduction of NO to NH₃ has been less explored. Herein, based on first-principles calculations, we propose a metal-free electrocatalyst, namely, P atom doped single-layer C₂N, as a promising candidate system for achieving the direct electroreduction of NO to NH₃. Particularly, double P doped C₂N (2P@C₂N) exhibits excellent catalytic activity and high selectivity, which correlates with the sp³ hybridization of the P atom. Moreover, our microkinetic modeling analysis shows that the turnover frequency of NO reduction to NH₃ on 2P@C₂N is as large as 8.9 × 10⁵ per s per site at 400 K, suggesting that it exhibits an ultra-fast reaction rate. Our study provides not only the first metal-free electrocatalyst for NO removal, but also an effective alternative avenue for ammonia synthesis.