CO在SnO2(110)面吸附特性的密度泛函研究  

Density Functional Study of the Properties of CO Adsorption on SnO_2(110) Surface

作　　者：薛严冰[1,2] 唐祯安[1] 

机构地区：[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

出　　处：《高等学校化学学报》2009年第3期583-587,共5页Chemical Journal of Chinese Universities

基　　金：国家“八六三”计划(批准号:2006AA040102,2006AA040106)资助

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.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 investi- gated. The results indicate that the most stable adsorption mode is associated to the CO with the C-end orien- ted to the five-coordinated Sn ion, and this adsorption mode improves the relaxation of the surface. The distri- bution 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.

关 键 词：气体传感器 吸附 密度泛函理论 态密度 

分 类 号：O641[理学—物理化学]