Perera Sahan D, Brotton Stephen J, Shinsato Haylie, Kaiser Ralf I, Choi Yuyeol, Na Kyungsu
Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States.
Department of Chemistry, Chonnam National University, Buk-gu, Gwangju 61186, South Korea.
J Phys Chem A. 2021 Jun 10;125(22):4896-4909. doi: 10.1021/acs.jpca.1c02892. Epub 2021 May 27.
Jet propulsion 10 (JP-10) droplets with and without aluminum nanoparticles in conjunction with HZSM-5 zeolite and surfactants were ultrasonically levitated, and their oxidation processes were explored to identify how the oxidation process of JP-10 is catalytically affected by the HZSM-5 zeolites and how the surfactant and Al NPs in the system impacted the key experimental parameters of the ignition such as ignition delay time, burn rate, and the maximum temperatures. Singly levitated droplets were ignited using a carbon dioxide laser under an oxygen-argon atmosphere. Pure JP-10 droplets and JP-10 droplets with silicon dioxide of an identical size distribution as the zeolite HZSM-5 did not ignite in strong contrast to HZSM-5-doped droplets. Acidic sites were found to be critical in the ignition of the JP-10. With the addition of the surfactant, the characteristic features of the JP-10 ignition were improved, so the ignition delay time of the zeolite-JP-10 samples were decreased by 2-3 ms and the burn rates were increased by 1.3 to 1.6 × 10 K s. The addition of Al NPs increased the maximum temperatures during the combustion of the systems by 300-400 K. Intermediates and end products of the JP-10 oxidation over HZSM-5 were characterized by UV-vis emission and Fourier-transform infrared transmission spectroscopies, revealing key reactive intermediates (OH, CH, C, O, and HCO) along with the HO molecules in highly excited rovibrational states. Overall, this work revealed that acetic sites in HZSM-5 are critical in the catalytic ignition of JP-10 droplets with the addition of the surfactant and Al NPs, enhancing the oxidation process of JP-10 over HZSM-5 zeolites.
对含有和不含铝纳米颗粒的喷气推进剂10（JP - 10）液滴与HZSM - 5沸石及表面活性剂的混合物进行超声悬浮，并探究其氧化过程，以确定HZSM - 5沸石如何催化影响JP - 10的氧化过程，以及体系中的表面活性剂和铝纳米颗粒如何影响点火的关键实验参数，如点火延迟时间、燃烧速率和最高温度。在氧 - 氩气氛下，使用二氧化碳激光点燃单悬浮液滴。与掺杂HZSM - 5的液滴形成强烈对比的是，纯JP - 10液滴和具有与HZSM - 5沸石相同尺寸分布的二氧化硅的JP - 10液滴未被点燃。发现酸性位点对JP - 10的点火至关重要。添加表面活性剂后，JP - 10点火的特征得到改善，因此沸石 - JP - 10样品的点火延迟时间减少了2 - 3毫秒，燃烧速率提高了1.3至1.6×10 K/s。添加铝纳米颗粒使体系燃烧过程中的最高温度提高了300 - 400 K。通过紫外 - 可见发射光谱和傅里叶变换红外透射光谱对HZSM - 5上JP - 10氧化的中间体和最终产物进行了表征，揭示了关键的反应中间体（OH、CH、C、O和HCO）以及处于高激发振转态的HO分子。总体而言，这项工作表明，在添加表面活性剂和铝纳米颗粒的情况下，HZSM - 5中的酸性位点对JP - 10液滴的催化点火至关重要，增强了JP - 10在HZSM - 5沸石上的氧化过程。
