Two-Dimensional MOF Constructed by a Binuclear-Copper Motif for High-Performance Electrocatalytic NO Reduction to NH3.

Abstract

Ambient electrochemical NO reduction presents a dual solution for sustainable NO reduction and NH₃ synthesis. However, their complex kinetics and energy demands necessitate high-performance electrocatalysts to ensure effective and selective process outcomes. Herein, we report that a two-dimensional Cu-based metal-organic framework (MOF), {[Cu(HL)]·H₂O} _n , (Cu-OUC, H₃L = 5-(2'-carboxylphenoxy)isophthalic acid) acts as a stable electrocatalyst with high efficiency for NO-to-NH₃ conversion. Electrochemical experimental studies showed that in 0.1 M K₂SO₄ solution, the as-prepared Cu-OUC achieved a peak Faradaic efficiency of 96.91% and a notable NH₃ yield as high as 3415.82 μg h^-1 mg^-1. The Zn-NO battery in aqueous solution can produce electricity possessing a power density of 2.04 mW cm^-2 while simultaneously achieving an NH₃ yield of 616.92 μg h^-1 mg^-1. Theoretical calculations revealed that the surface of Cu-OUC effectively facilitates NO activation through a two-way charge transfer mechanism of "electron acceptance and donation", with the *NO formation step being the potential-determining stage. The study pioneers the use of a MOF as an electrocatalyst for ambient NO-to-NH₃ conversion.