Sustainable Electrosynthesis of Value-Added Ammonia and 5,5′-Azotetrazolate Energetic Materials Enabled by Bifunctional Cu–Fe3O4 Heterostructures

Abstract

Conventional ammonia electrosynthesis via the nitrite reduction reaction (NO2RR) is generally paired with the anodic oxygen evolution reaction (OER). However, the intrinsically sluggish kinetic of the OER severely limits the overall energy efficiency of such electrolysis system. Integrating the NO2RR with thermodynamically favorable electrooxidation of organic substrates emerges as a feasible strategy for energy-efficient ammonia synthesis, which also enables the synchronous generation of value-added chemicals. Herein, we design and construct a Cu–Fe3O4 heterostructure catalyst supported on iron foam (IF) (Cu–Fe3O4/IF) and demonstrate its exceptional performances for NO2RR and 5-aminotetrazole oxidation reaction (5-ATOR) for the first time. At −0.4 V vs RHE, the Cu–Fe3O4/IF affords a prominent Faradaic efficiency of 94.2% and a high NH3 yield rate of 15.87 mg h–1 cm–2. Impressively, a synergistic electrolytic system by coupling cathodic NO2RR with anodic 5-ATOR is successfully established, which realizes the efficient coproduction of ammonia and 5,5′-azotetrazolate energetic materials.