Electronic Activation of Ni−OH via Vanadium Doping and Oxygen Vacancy Engineering for Electrosynthesis of 4,4’-Diaminoazofurazan

Abstract

The sustainable manufacturing of strategic energetic materials is impeded by hazardous oxidants and poor atom economy in conventional syntheses. Herein, we report a green and controllable electrochemical oxidative coupling route toward high-performance 4,4′-diaminoazofurazan (DAAzF) using a vanadium-doped NiO nanosheet electrocatalyst (V1-NiO) in-situ grown on nickel foam. Combined experimental characterizations and density functional theory (DFT) calculations demonstrate that V doping induces strong charge redistribution and new orbital hybridization, which significantly downshift the d-band center of Ni sites and optimize the adsorption−desorption behavior of hydroxyl species. Such electronic modulation effectively lowers the energy barrier for NiOOH generation and accelerates proton abstraction from DAF molecules. Reaction pathway analysis reveals that V1-NiO enables a thermodynamically more favorable route with a much lower rate-determining step energy barrier, facilitates rapid OH− regeneration and proton migration, and promotes efficient N−N coupling without extra OH− replenishment. The as-obtained V1-NiO catalyst delivers a low onset potential of 1.29 V vs RHE, which is 50 mV lower than that of pristine NiO. This work provides a universal electronic-structure and vacancy-engineering strategy for transition metal oxides, and offers a promising paradigm for the green electrosynthesis of nitrogen-rich energetic compounds.