Dehydrogenative Coupling of LLM-116 over Copper–Nickel Oxide Nanoparticles: TEMPO-Mediated Homogeneous Electrocatalysis

The electrosynthesis of 1,2-bis(3,5-dinitro-1H-pyrazol-4-yl)diazene (H2NPA) attained a notably high Faradaic efficiency (FE) of 81.69% in 0.1 M LiOH at 1.65 VRHE with CuO–NiO spherical nanoparticles as the anode and 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) as the electrocatalytic mediator, effectively circumventing the environmental contamination and heterogeneous oxidation associated with strong oxidants. This synergistic catalysis facilitates the synthesis of six derivatives at a lower potential, resulting in substantial energy savings. NiO doping demonstrates a significant catalytic effect, with NiOOH serving as the critical active component. TEMPO facilitates favorable thermodynamics by offering a more suitable reduction potential. Mechanism studies indicate that coupling of the active group −NH occurs prior to dehydrogenation. This study presents a novel strategy for the organic electrosynthesis of nitro-containing energetic materials, leveraging the synergistic catalysis of electrode materials and electrocatalytic mediators.