Dehydrogenative\nCoupling of LLM-116 over Copper–Nickel\nOxide Nanoparticles: TEMPO-Mediated Homogeneous Electrocatalysis

The electrosynthesis of 1,2-bis(3,5-dinitro-1<i>H</i>-pyrazol-4-yl)diazene (H<sub>2</sub>NPA) attained a notably\nhigh\nFaradaic efficiency (FE) of 81.69% in 0.1 M LiOH at 1.65 V<sub>RHE</sub> with CuO–NiO spherical nanoparticles as the anode and 2,2,6,6-tetramethylpiperidine-<i>N</i>-oxyl (TEMPO) as the electrocatalytic mediator, effectively\ncircumventing the environmental contamination and heterogeneous oxidation\nassociated with strong oxidants. This synergistic catalysis facilitates\nthe synthesis of six derivatives at a lower potential, resulting in\nsubstantial energy savings. NiO doping demonstrates a significant\ncatalytic effect, with NiOOH serving as the critical active component.\nTEMPO facilitates favorable thermodynamics by offering a more suitable\nreduction potential. Mechanism studies indicate that coupling of the\nactive group −NH occurs prior to dehydrogenation. This study\npresents a novel strategy for the organic electrosynthesis of nitro-containing\nenergetic materials, leveraging the synergistic catalysis of electrode\nmaterials and electrocatalytic mediators.