氧分子在Pt低指数面上的吸附和解离

应用原子和表面簇合物相互作用的5参数Morse势方法(简称5-MP)构造推广的LEPS势对O₂-Pt分子体系进行了系统的研究, 获得了O₂分子在Pt的2个低指数面(111)和(110)重构面上的吸附几何、结合能和振动频率等临界点性质; 计算结果显示O₂在Pt(111)面上难解离, 且存在超氧化吸附态, 同时, 应用表面分子解离限和晶面解离距的概念分析了(111)面上的解离机理; 并根据分子指纹性质, 将O₂在Pt(110)缺行重构面上出现的振动频率860, 930, 1250 cm^－1进行了合理的指派.

Adsorption and Dissociation of O2 on Pt Low Index Surfaces

The extended London-Enyring-Polanyi-Sato (LEPS) of O2-Pt single crystal plane systems was constructed by means of the 5-parameter Morse potential (5-MP). Both adsorption and dissociation of O2 on Pt low index surfaces mainly including (111) and (110) reconstruction surfaces were investigated with ex- tended LEPS in detail. All critical characteristics of the system obtained, such as adsorption geometry, bind- ing energy, eigenvalues for vibration, etc., were in good agreement with the experimental results. Our calcu- lated results suggested that the dissociation of O2 on Pt(111) surface should be difficult and superoxo-like state would exist likely. Meanwhile, the concepts of the molecular dissociation limit and the surface disso- ciation distance were used to analyze the dissociation mechanism of O2 on Pt(111) surface. Moreover, the vibration frequencies of 860, 930 and 1250 cm-1 produced by O2 adsorbed on Pt(110) reconstruction surface were assigned logically on the basis of the properties of the molecular fingerprint.