物理化学学报 >> 1998, Vol. 14 >> Issue (02): 103-108.doi: 10.3866/PKU.WHXB19980202

研究论文 上一篇    下一篇

A+B2表面催化反应相变及自振荡的蒙特卡罗模拟

曾健青, 张镜澄, 钟炳   

  1. 中国科学院广州化学研究所，广州 510650|中国科学院山西煤炭化学研究所 煤转化国家重点实验室，太原 030001
  • 收稿日期:1997-03-17 修回日期:1997-07-28 发布日期:1998-02-15
  • 通讯作者: 曾健青

Monte Carlo Simulation of the Phase Transition and Self-oscillation in A+B2 Surface Catalytic Reaction

Zeng Jian-Qing, Zhang Jing-Cheng, Zhong Bing   

  1. Guangzhou Institute of Chemistry,Chinese Academy of Sciences,Guangzhou 510650|The State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001
  • Received:1997-03-17 Revised:1997-07-28 Published:1998-02-15
  • Contact: Zeng Jian-Qing

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摘要：

用Monte Carlo法研究了脱附和E－R机理对不可逆催化氧化反应A＋1／2B2→AB的相交和自振荡的影响、结果表明，（1）催化剂表面A的脱附使ZGB模型中的一级相变点消失，但对二级相交点的影响很小；当有E－R机理参与时，二级相交点消失，且E－R过程的几率对一级相交点的影响较大；当A的脱附和E－R过程同时起作用时，上述反应不存在相交（2）在ZGB模型中的二级相变点附近，反应速率随时间的变化具有明显的振荡现象，在其它位置主要表现为噪音. 引入A的脱附后在二级相交点附近明显的自振荡现象依然存在；当E-R过程起作用时，随着二级相交点的消失，明显的振荡现象亦随之消失．（3）A的脱附和E－R过程对上述反应相变的影响与A的表面扩散对相变的影响有着本质的区别，因为后者只能改变相变点的位置而不能改变相变点的存在状况．

关键词: 蒙特卡罗模拟, 表面催化反应, 相变, 自振荡, 脱附, E-R机理

Abstract:

The influences of A desorption and E-R mechanism on the phase transitions and self-oscillations in the irreversible catalytic oxidation reaction of A + 1/2 B2 → AB were studied in detail by Monte Carlo simulation. It was found that (1) the first order phase point observed in ZGB model disappears when A desorption is considered; (2) the second order phase transition point observed in ZGB model disappears when E-R mechanism concerned with A(g) and adsorbed B atom is considered; (3) there is no phase transitions in the reaction when both A desorption and E-R mechanism are considered; (4) there is obvious rate oscillation in the neighbourhood of the second order phase transition point of ZGB model, but only noise at other positions of A partial pressure, so there are no oscillations when E-R mechanism is considered or both E-R mechanism and A desorption are considered in our extended model.

Key words: Monte Carlo simulation, Surface catalytic reaction, Phase transition, Selfoscillation, Desorption, E-R mechanism