高等学校化学学报

高等学校化学学报

• 研究论文 • 上一篇    下一篇

CO在SnO2(110)面吸附特性的密度泛函研究

薛严冰1,2, 唐祯安1   

    1. 大连理工大学电子与信息工程学院, 大连 116024;
    2. 大连交通大学电气信息学院, 大连 116028
  • 收稿日期:2008-02-28 修回日期:1900-01-01 出版日期:2009-03-10 发布日期:2009-03-10
  • 通讯作者: 薛严冰

Density Functional Study of the Properties of CO Adsorption on SnO2(110) Surface

XUE Yan-Bing1,2*, TANG Zhen-An1   

    1. School of Electronic and Information Engineering, Dalian University of Technology, Dalian 116024, China;
    2. School of Electronics and Information Engineering, Dalian Jiaotong University, Dalian 116028, China
  • Received:2008-02-28 Revised:1900-01-01 Online:2009-03-10 Published:2009-03-10
  • Contact: XUE Yan-Bing

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摘要： 根据密度泛函理论, 采用广义密度近似和总体能量平面波赝势方法, 以6层Slab周期结构为模型, 计算了CO以4种不同方式在SnO2(110)表面的吸附, 研究了CO吸附对表面特性的影响. 计算结果表明, CO以C端向下在低配位Sn5C位置的顶位吸附为稳定的吸附方式, 该吸附对表面的驰豫现象有所改善. CO吸附并未明显改变表面电子态密度分布, 但造成了费米能1.06 eV的升高. 吸附后CO分子向表面转移了0.07个电子, 使表面电阻下降. 理论计算的结果支持了气体传感器气敏机理中的表面电导模型.

关键词: 气体传感器, 吸附, 密度泛函理论, 态密度

Abstract: Based on density functional theory in the generalized gradient approximation, together with the total energy plane-wave Pseudopotential, adopted a six-layers periodic slab model, four modes of CO adsorption on SnO2 (110) surface were calculated and the surface property modifications due to CO adsorption were investigated. The results indicate that the most stable adsorption mode is associated to the CO with the C-end oriented to the five-coordinated Sn ion, and this adsorption mode improves the relaxation of the surface. The distribution of the electronic states of surface has no remarkable change after CO adsorption, but the Fermi level has 1.06 eV shift to a high-energy direction. Adsorption resulted in a 0.07 electron transfer from CO molecule to the surface, which causes the decrease of the surface resistance. The present results favor the surface conduc-tance model of the sensitive mechanism of gas sensors.

Key words: Gas sensor, Adsorption, Density functional theory, Density of state

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