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

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-N-6-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 & mu;mol 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 & mu;g 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.

Automated summary

An atomic copper-iron dual-site electrocatalyst anchored on nitrogen-doped carbon has been developed for electrocatalytic reduction of nitric oxide to ammonia. The CuFe DS/NC catalyst exhibited significantly better performance compared to other single-atom catalysts, with a high Faraday efficiency of 90% and a yield rate of 112.52 μmol cm(-2) h(-1) at -0.6 V versus RHE. Furthermore, the CuFe DS/NC catalyst showed promising results in a proof-of-concept Zn-NO battery. Theoretical calculations suggested that the bimetallic sites played a crucial role in promoting the electrocatalytic reaction.