Exploring Co3O4@NiMoO4 for the photoelectrocatalytic synthesis of energetic 5,5′-azotetrazole disodium salt

The green synthesis of energetic materials (EMs) is a challenging and critical research direction. Herein, we develop a Co 3 O 4 @ NiMoO 4 heterojunction photoanode for the photoelectrocatalytic (PEC) oxidation of 5-amino-1 H -tetrazole (5AT) to the 5,5'-azotetrazole disodium salt (SZT). The heterojunction, featuring NiMoO 4 nanosheets uniformly coated on Co 3 O 4 nanowire arrays, significantly enhances active site exposure and interfacial charge transfer. Mechanistic studies reveal that the heterostructure follows a direct Z-scheme charge transfer pathway, which not only promotes the separation of electron-hole pairs but also facilitates the efficient generation of ·OH radicals, thereby markedly enhancing the oxidation kinetics. Therefore, under PEC tests, the heterostructure achieves an oxidation potential of only 1.22 V vs. RHE at 10 mA·cm -2 in 0.2 M 5AT, which is 300 mV lower than that of pure Co 3 O 4 . Moreover, under the same PEC conditions, the electrode demonstrates excellent stability over 15 hours of continuous operation. Successful SZT formation is confirmed by UV-vis and NMR spectroscopy. This work provides an efficient and sustainable strategy for EMs synthesis via heterojunction-engineered PEC catalysis, highlighting its potential for safe and energy-efficient organic synthesis. This work introduces a Co 3 O 4 @NiMoO 4 heterojunction photoanode for the photoelectrocatalytic (PEC) oxidation of 5-amino-1H-tetrazole (5AT) to 5,5'-azotetrazole disodium salt (SZT). The Z-scheme heterostructure enhances charge separation and hydroxyl radical generation, enabling efficient PEC oxidation under mild conditions. This approach offers a sustainable alternative to traditional synthesis, advancing green strategies for the production of energetic materials through heterojunction-engineered catalysis. • Construction of Z-scheme Co 3 O 4 @NiMoO 4 heterojunction photoanode for efficient PEC oxidation of 5AT. • Heterojunction promotes ·OH radical generation and charge separation, reducing oxidation potential by 300 mV vs Co 3 O 4 • A sustainable and stable PEC system enables the green synthesis of energetic materials with 15-hour continuous operation.