铂族金属氧化过程中的簇发振荡及其诱发机理

铂族金属表面氧化过程是典型的多相催化反应之一, 具有广泛的应用背景及丰富的振荡行为, 因此深入研究铂族金属的氧化中的物理及化学过程具有重要的理论意义及工程应用前景. 通过对铂族金属CO的氧化过程中实测数据的回归分析, 建立了不同尺度耦合解析动力学理论模型. 通过对平衡态的稳定性分析, 指出在一定条件下稳态解会由鞍-结同宿轨道分岔导致周期振荡. 当快子系统产生Hopf分岔时, 该周期振荡会进一步演化为两尺度耦合的周期簇发振荡, 即N^k振荡, 并由加周期分岔使得系统处于激发态的时间显著增加.在此基础上, 利用分岔理论进一步分析了周期簇发及加周期分岔的产生机理, 揭示了周期簇发中沉寂态和激发态相互转化时的不同分岔模式.

Bursting oscillations and the bifurcation mechanism in oxidation on platinum group metals

Applying the regression analysis to the measured data in CO oxidation on platinum group metals, a analytical theory model with different time scales is established in this paper. The stabilities of equilibria are discussed in detail, and different types of the solutions may bifurcate from the equilibria with the change of the parameters. With a certain parameter, the system can exhibit periodic oscillations via the saddle-node homoclinic orbit bifurcation, which can evolve into periodic bursting, owing to Hopf bifurcation of the fast subsystem. The bifurcation connecting the quiescent state and the repetitive spikes is presented to account for the occurrence of the N^k oscillations. Furthermore, the mechanism of sequence of the period-adding bifurcations is explored to reveal why the length of the sequences become longer with the variation of the parameters.