Oxygen-Bridged Copper-Iron Atomic Pair as Dual-Metal Active Sites for Boosting Electrocatalytic NO Reduction

Abstract

Electrocatalytic reduction of nitric oxide (NO) to ammonia (NH₃ ) is a promising approach to NH₃ synthesis. However, due to the lack of efficient electrocatalysts, the performance of electrocatalytic NO reduction reaction (NORR) is far from satisfactory. Herein, it is reported that an atomic copper-iron dual-site electrocatalyst bridged by an axial oxygen atom (OFeN₆ Cu) is anchored on nitrogen-doped carbon (CuFe DS/NC) for NORR. The CuFe DS/NC can significantly enhance the electrocatalytic NH₃ synthesis performance (Faraday efficiency, 90%; yield rate, 112.52 µmol cm^-2 h^-1 ) at -0.6 V versus RHE, which is dramatically higher than the corresponding Cu single-atom, Fe single-atom and all NORR single-atom catalysts in the literature so far. Moreover, an assembled proof-of-concept Zn-NO battery using CuFe DS/NC as the cathode outputs a power density of 2.30 mW cm^-2 and an NH₃ yield of 45.52 µg h^-1 mg_cat ^-1 . The theoretical calculation result indicates that bimetallic sites can promote electrocatalytic NORR by changing the rate-determining step and accelerating the protonation process. This work provides a flexible strategy for efficient sustainable NH₃ synthesis.

Keywords: NH3 synthesis; NO reduction; dual-site catalysts; electrocatalysis; synergistic effect.