SO_2－O_2－H_2O表面催化反应“干”机理的研究

ON THE “DRY” MECHANISM OF THE SO 2 O 2 H 2O CATALYTIC SUFACE REACTIONReceived:1995-10-02 The project is supported by the National Natural Science Foundation of China (No.29277276)

ＳＯ２－Ｏ２－Ｈ２Ｏ表面催化反应机制的研究是环境科学中的一个重要课题．用格子模型研究了该反应的“干”机理．利用“部分模拟法”得到了三种情况下反应体系的动力学相图：１）无表面吸附物种的脱附；２）吸附态分子Ｏ２＊或Ｈ２Ｏ＊有一种可脱附；３）Ｏ２＊和Ｈ２Ｏ＊都可脱附．计算表明，在无脱附的情况下相图上的反应相是一个点；在有一个物种脱附的情况下反应相扩展到一个线性区域；在有两个物种脱附的情况下反应相进一步扩展，成为一个一定大小的面区域．该结果说明，反应物种的脱附对ＳＯ２－Ｏ２－Ｈ２Ｏ表面反应的持续进行具有关键性的作用．

Study of mechanisms of the SO 2 O 2 H 2O catalytic surface reaction is an important topic in environmental science.The 'dry' mechanism of this reaction is studied with a lattice model. Kinetic phase diagrams of the reaction system are determined, by the partial simulation method, in three cases:1) no desorption,2) O 2* or H 2O* desorption,3)O 2* and H 2O* desorption.It is found that the steady reactive phase may be a point, a linear region or a definite area on the phase diagram, corresponding to case 1),2) or 3) respectively. The results indicate that for this reaction the desorption of adsorbed species is crucial to the existence of an extended reactive region.