Abstract

The stability and performance of nitrate ester-based energetic materials may be compromised by their degradation, which is primarily promoted by the NO_x. To overcome this issue, the typical approach is the addition of stabilizers to the original formulation of the energetic materials. However, this is not always suitable, particularly if pure materials are needed. Thus, this work presents a new method consisting of capturing the released NO_x on activated carbons impregnated with TiO₂ nanoparticles. The principle is to perform the oxidation of NO_x to HNO₃ by photocatalysis in presence of TiO₂. Consequently, four different activated carbons are prepared by chemical activation with ZnCl₂ and H₃PO₄ to achieve diverse textural and functional properties. They are subjected to impregnation with 1 wt. % of TiO₂. Hence, they are thoroughly characterized by means of nitrogen sorption isotherms, Fourier transform infrared spectroscopy and X-ray fluorescence. Afterwards, their efficiency under different light conditions is assessed through the capture of NO_x evolved from the accelerated degradation of nitrocellulose quantified by Bergmann-Junk test. The quantity of captured NO_x is determined by ion chromatography. The results show that a combination of a micro and mesoporous material with low surface functions is the optimal criterion to achieve the desired deposition rate of TiO₂. This is obtained by the heat-treated activated carbon synthetized using H₃PO₄. In addition, more than 60% of the released NO_x are efficiently captured by the prepared materials under ultraviolet light, corresponding to 0.0723 mmol of NO_x per gram of impregnated activated carbon.

摘要

硝酸酯基高能材料的稳定性和性能可能会因其降解而受到损害，而降解主要是由NO _x促进的。为了克服这个问题，典型的方法是在高能材料的原始配方中添加稳定剂。但是，这并不总是合适的，特别是在需要纯净材料的情况下。因此，这项工作提出了一种新方法，该方法包括捕获用TiO ₂纳米颗粒浸渍的活性炭上释放的NO _x。原理是在TiO ₂存在下通过光催化将NO _x氧化为HNO ₃。。因此，通过用ZnCl ₂和H ₃ PO ₄进行化学活化来制备四种不同的活性炭，以实现多种质地和功能特性。它们以1重量％的量浸渍。TiO _2的％。因此，它们通过氮吸附等温线，傅立叶变换红外光谱和X射线荧光进行了彻底表征。然后，它们的不同光照条件下效率是通过NO的捕获评估_X从由硝酸纤维素贝格曼-垃圾测试定量的劣化加速发展而来的。捕获的NO _x量通过离子色谱法测定。结果表明，具有低表面功能的微孔材料和中孔材料的组合是实现所需TiO ₂沉积速率的最佳标准。这是通过使用H ₃ PO ₄合成的经热处理的活性炭而获得的。另外，所制备的材料在紫外线下有效地捕获了超过60％的释放的NO _x，相当于每克浸渍的活性炭0.0723mmol的NO _x。