Unveiling Electrode–Electrolyte Design-Based NO Reduction for NH₃ Synthesis

Abstract

The electrochemical N2 reduction reaction has attracted interest as a potential alternative to the Haber–Bosch process, but a significantly low conversion efficiency and a significantly low ammonia production rate stimulate the need for alternatives. Here, we represent the electrochemical reduction of nitric oxide (NO) on a nanostructured Ag electrode in combination with a rationally designed electrolyte containing the EDTA–Fe2+ metal complex (EFeMC), which results in an ∼100% efficiency for NH3 with a current density of 50 mA/cm2 at −0.165 VRHE, without any degradation in catalytic activity or product selectivity up to 120 h. Economic analysis using itemized cost estimation predicted that the synthesis of ammonia from NO reduction in an EFeMC-designed electrolyte can be market competitive at an electricity price of $0.03 kWh–1 with a current density of >125 mA/cm2. Therefore, this approach opens an entirely new avenue of renewable electricity-driven ammonia synthesis.