Unveiling the Role of Oxygen Vacancies in Manganese Oxides for the Ammonium Perchlorate Thermal Decomposition

作者：Xin Huang, Yuan Bian, Bo Wu, Xiaohui Duan, Zhongliang Xiao, Jin Shen, Zhaoqian Li, Xun Liu, Chonghua Pei · 发表于：Inorganic Chemistry · 年份：2025 · DOI：10.1021/acs.inorgchem.5c03436 · 被引用次数：6 · 研究领域：Energetic Materials and Combustion、Thermal and Kinetic Analysis、Extraction and Separation Processes

Manganese oxides (MnO 2, Mn 2 O 3, and Mn 3 O 4 ) were synthesized as catalysts to promote the ammonium perchlorate (AP) thermal decomposition, and the potential catalytic mechanisms were systematically researched. The catalytic activity followed the order of MnO 2 > Mn 3 O 4 > Mn 2 O 3 . The electron paramagnetic resonance (EPR) results showed that MnO 2 has the highest content of superoxide (·O 2 – ), followed by Mn 3 O 4 and Mn 2 O 3, which is consistent with the oxygen vacancy (Ov) content. Significantly, the decrease in the Ov concentration of MnO 2 -T, Mn 2 O 3 -T, and Mn 3 O 4 -T after the annealing treatment resulted in a decrease in the catalytic performance and catalytic reaction rate k . The inhibitory effect due to the NH 3 accumulation on the AP surface was well resolved by MnO 2 . Density functional theory (DFT) calculation results show that O 2 can be activated to ·O 2 – at the Ov, and the O–O bond is elongated from 1.22 to 1.30 Å. The Mn 5c /Mn 4c sites on the MnO 2 surface were found to strongly adsorb NH 3 . The Ov and Lewis acid sites (Mn 5c /Mn 4c ) synergistically anchor O 2 and NH 3 on the catalyst surface and shorten the reaction distance through the Langmuir–Hinshelwood (L-H) mechanism, thereby endowing MnO 2 with more favorable conditions for catalyzing AP thermal decomposition.