三维氧化铁/石墨烯的构建及其对CL-20的热分解性能的影响

Construction of Three-Dimensional Hematite/Graphene with Effective Catalytic Activity for the Thermal Decomposition of CL-20

首先采用水热法合成了两种不同形貌的氧化铁(棒状rFe2O3和颗粒状pFe2O3),然后采用界面自组装法制备了两种具备高比表面积和三维网状结构的氧化铁与石墨烯的复合物(rFe2O3/G和pFe2O3/G)。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电镜(TEM)和X射线光电子能谱(XPS)对样品的相态、组成及结构性质进行确证。根据热重-红外联用分析(TGA-IR)和差式扫描量热法(DSC)测试对所制备的催化剂对CL-20的催化热分解活性进行评估。通过逻辑选择法对Cl-20、Fe2O3/Cl-20和Fe2O3/G/CL-20的非等温热分解动力学进行系统研究发现,其均遵循相同的机理函数模型。对比分析表明,棒状氧化铁/石墨烯复合物(rFe2O3/G)对CL-20的热分解表现出最佳的催化活性。以rFe2O3及rFe2O3/G为样本,研究其对CL-20撞击感度的影响。测试结果表明,rFe2O3/G比rFe2O3更能有效降低Cl-20的撞击感度。综合分析可知,rFe2O3与石墨烯的结合不仅能够促进Cl-20的热分解,且能同时提高Cl-20的安全性能。

High-performance solid propellants are very important for the development of modern weapons. Aside from their high energy and high burning rate, safety performance is regarded as the most important factor that should be considered whenever a new solid propellant recipe is formulated. Therefore, exploring a new type of combustion catalyst that can improve both catalytic activity and reduce the sensitivity of the energetic component is significant. Traditionally, transition metals or metal oxides are used as a combustion catalyst for accelerating the thermal decomposition of energetic components. However, the existing problem of these catalysts is the aggregation of particles accompanied by poor surface area. Coupling metal oxides with graphene is a promising approach to obtain a binary composite with stable structure and large specific surface area. In this work, rod-like and granular Fe2O3 nanoparticles were synthesized using a hydrothermal method. Then, the two as-prepared Fe2O3 nanoparticles were coupled with graphene sheets using an interfacial selfassembly method, which can effectively prevent the aggregation of Fe2O3 particles and simultaneously increase the active sites that participate in the reaction. X-ray diffraction and X-ray photoelectron spectroscopy were used to identify the phase states and chemical compositions of the prepared samples. The morphology and internal structures were further demonstrated through scanning electron microscopy, transmission electron microscopy and nitrogen adsorptiondesorption tests. Both phase analysis and structure identification indicate that the prepared Fe2O3/G has high purity and high surface area. The catalytic performance of the prepared Fe2O3 and Fe2O3/G in the thermal decomposition of hexanitrohexaazaisowurtzitane(CL-20) was evaluated based on thermal gravimetric analysis-infrared spectroscopy(TGAIR) and differential scanning calorimetry(DSC) tests. The non-isothermal decomposition kinetics of CL-20, Fe2O3/CL-20, and Fe2O3/G/CL-20 were further studied by DSC. The results reveal the excellent catalytic activity of Fe2O3/G in the thermal decomposition of CL-20, which is attributed to the presence of abundant pore structure and large surface area. The reaction mechanisms of the exothermic decomposition process of CL-20, Fe2O3/CL-20, and Fe2O3/G/CL-20 were obtained by the logical choice method, and the composites all followed same mechanism function model as CL-20. Through comparison, the rod-like Fe2O3 coupled with graphene was found to have the best catalytic activity in the thermal decomposition of CL-20. Thus, the rod-like Fe2O3 and its Fe2O3/G composite were used to investigate their influence on the impact sensitivity of CL-20 by fall hammer apparatus. The results show that rFe2O3/G can effectively decrease the impact sensitivity of CL-20 compared with pure CL-20 and rFe2O3/CL-20. Therefore, r e2O3 coupled with graphene not only promotes the thermal decomposition but also improves the safety performance of CL-20.