Agnihotri Ruchika, Oommen Charlie
Department of Aerospace Engineering, Indian Institute of Science Bangalore 560012 India
RSC Adv. 2018 Jun 19;8(40):22293-22302. doi: 10.1039/c8ra02368a.
Hydroxylammonium nitrate (HAN) is an energetic ionic liquid which is fast emerging as a promising environmentally friendly, high performing monopropellant for space propulsion application. The high performance due to the higher adiabatic temperature for HAN based compositions also poses challenges as high temperature tolerant catalysts have to be developed for its decomposition. A novel cobalt doped cerium oxide based catalyst has been prepared by the co-precipitation route and characterized by SEM/EDS, XRD, and XPS. The effectiveness of the catalyst in decomposing HAN has been tested using thermo-analytical techniques. An evolved gas analysis (EGA) to examine decomposition products and the possible reaction mechanism was also performed using the hyphenated DTA-TG-FTIR technique. Formation of an Ce/Ce ion couple in ceria during co-precipitation was found to be critical in deciding the reactivity of HAN decomposition over the catalyst. The activity of the catalyst was also examined in a batch reactor for its longevity. The prepared catalyst was found to be more versatile and durable than a hitherto reported alumina supported iridium catalyst in the present studies.
硝酸羟胺（HAN）是一种含能离子液体，作为一种有前景的环保型高性能单组元推进剂，正迅速崛起并应用于航天推进领域。由于基于HAN的组合物具有较高的绝热温度，其高性能也带来了挑战，因为必须开发耐高温催化剂来促进其分解。通过共沉淀法制备了一种新型钴掺杂氧化铈基催化剂，并通过扫描电子显微镜/能谱仪（SEM/EDS）、X射线衍射仪（XRD）和X射线光电子能谱仪（XPS）对其进行了表征。使用热分析技术测试了该催化剂分解HAN的有效性。还使用联用的差示热分析-热重分析-傅里叶变换红外光谱（DTA-TG-FTIR）技术进行了逸出气体分析（EGA），以检查分解产物和可能的反应机理。发现在共沉淀过程中氧化铈中形成Ce/Ce离子对对于决定催化剂上HAN分解的反应活性至关重要。还在间歇式反应器中考察了该催化剂的寿命。在本研究中，发现所制备的催化剂比迄今报道的氧化铝负载铱催化剂更具通用性和耐久性。
