Plasma-Enabled Electrocatalytic Reduction of Nitrogen Oxides to Ammonia over Cu-N-P Catalysts

The electrocatalytic reduction of nitrogen oxides (NO x ) to ammonia represents a promising alternative to direct N 2 reduction but is often limited by low reaction rates, poor selectivity, and severe competition from hydrogen evolution under dilute feed conditions. Here, we report a plasma-enabled electrocatalytic strategy for efficient NO x -to-NH 3 conversion using an electronically engineered Cu-N-P catalyst. A rotating gliding arc plasma converts air into reactive NO x species, providing a continuous and controllable feed for downstream electrochemical reduction. The Cu-N-P catalyst achieves an ammonia production rate of 2.36 mmol h −1 cm −2 with nearly 100% Faradaic efficiency at −0.575 V versus RHE and maintains stable operation for over 125 h under plasma-derived NO x conditions. Compared with unmodified Cu, the N, P co-doped catalyst promotes selective NO x adsorption and accelerates the hydrogenation of key intermediates while suppressing parasitic hydrogen evolution. Spectroscopic characterizations and theoretical analysis reveal that electronic structure modulation facilitates efficient NO x utilization and favorable hydrogenation kinetics. This work establishes an effective catalytic pathway for NO x -to-ammonia conversion under plasma-assisted conditions, providing insights into catalyst design for coupled plasma-electrochemical nitrogen conversion systems.