Efficient electrocatalytic nitric oxide reduction to ammonia using manganese spinel oxides

The electrocatalytic nitric oxide (NO) reduction reaction (NORR) driven by renewable electricity is a sustainable route for air pollution treatment and ammonia (NH 3 ) synthesis. Herein, we report carbon fiber-supported CoMn 2 O 4 spinel oxide nanoparticles (CoMn 2 O 4 /C) for the electrocatalytic NORR to NH 3 . CoMn 2 O 4 /C delivers a maximum NH 3 faradaic efficiency of 89.3% with a yield rate of 497.6 mmol h −1 g −1 at −0.7 V versus a reversible hydrogen electrode ( vs. RHE), which is significantly better than that of CoMn 2 O 4 (325 mmol h −1 g −1 , 86.3%) under similar conditions. In situ Raman and theoretical calculations confirmed that the CoMn 2 O 4 /C composite catalyst contributed to optimizing the adsorption behavior of protons and NO on the CoMn 2 O 4 surface. The conductive carbon support coupling significantly enhances the NO adsorption energy of CoMn 2 O 4 and decreases the free energy change of the potential determining step (PDS) to *NHO, effectively promoting *NH 3 desorption and inhibiting the HER. This work provides a reference for the rational design of electrocatalysts for boosting NH 3 production.