摘要
飞行时间质谱结合分子束取样技术可以对以反应过程中的不稳定中间体、自由基以及稳定的产物进行原位取样,且分子之间不发生碰撞,可以有效地冷却不稳定产物。该方法可用于热解及多相催化等复杂反应中瞬态物种的探测。我们研制了新型常压催化反应器与真空紫外单光子电离分子束质谱联用装置,建立了气、液、固复杂反应体系原位诊断技术和方法。该装置在甲烷催化转化实验中直接探测到甲基自由基和C_3、C_4、C_7中间体,为该反应机理的推测提供可靠的实验证据~([1]);对金属纳米颗粒进行原位全分析,可以研究配体在纳米颗粒上的解离过程,理解不同配体的解离通道~([2]);在煤热解过程中可以进行原位热重质谱分析,研究气相产物的组成和逸出规律,有利于全面认识煤的化学组成和结构~([3])。
Time-of-flight mass spectrometry coupled with molecular beam sampling technique can be employed to identify the unstable intermediates and radicals in the pyrolysis and heterogeneous catalysis reaction process.A novel catalytic reactor combined with vacuum ultraviolet singlephoton ionization time-of-flight mass spectrometry(VUV-SPI-MS) is used for understanding the mechanism of catalytic conversion of methane.Mass spectrum of radical(methyl) and intermediates(C_3,C_4,and C_7) are obtained,which provide strong experimental evidence for catalytic mechanism speculation.In situ of the metal nanoparticle and coal pyrolysis analysis,we can study the ligand dissociation process on nanoparticles,the chemical composition and structure of coal.
引文
[1]Guo X.;Fang G.;Li G.;Ma H.;Tang Z.;Bao X.et al.Science.2014,344:616.
[2]Yang H.;Shi L.;Tang Z.;Zheng N.et al.J.Am.Chem.Soc.2013,135,9568.
[3]Li G.;Zhang S.;Tang Z.;Hu Q.et al.Fuel Processing Technology.2015,133,232.