基于密度泛函理论计算的CO_2在SrTiO_3(100)表面的吸附

Calculation of CO_2 Adsorption on SrTiO_3(100) with Density Functional Theory

通过密度泛函理论的第一性原理,模拟了CO2分子在SrTiO3(100)表面TiO2-和SrO-位点上的吸附行为,获得了CO2在几种不同吸附模型下的结构参数及表面吸附能,进而研究了吸附机理和结构稳定性.计算结果表明,当CO2的C原子吸附在SrTiO3(100)表面SrO-及TiO2-位点的氧原子上时,吸附结构较稳定,尤其是C、O原子共吸附在TiO2-位点时最稳定,而其余吸附模型则不稳定.对吸附稳定模型的Mulliken布局数及态密度分析显示:CO2分子在SrTiO3(100)表面吸附主要是由于SrTiO3(100)面的电子跃迁至CO2分子,CO2分子得到电子形成弯曲的CO2-阴离子结构,并伴随着C-O键的伸长,从而达到吸附活化CO2的目的.

Based on the first-principle of density functional theory（DFT）,adsorption of carbon dioxide（CO2） on both SrO-and TiO2-terminated SrTiO3（100） surfaces was simulated and the adsorption energies and structure parameters were obtained under several different models,which would be valuable for disclosing the adsorption mechanism and structural stability.It was found that the structures which C atom of CO2 adsorbed on SrTiO3（100） surface were more stable,especially for co-adsorption of both C and O atoms on TiO2-terminated,while the remaining adsorption models unstable.The analysis of the mulliken charges and the density of state（DOS） to such the stable adsorption models showed that the adsorption of CO2 on SrTiO3（100） surface was dominated by the electronic on SrTiO3（100） surface transitions to CO2.The bent structure CO2-anion was formed by CO2 catching an electron,and was accompanied by the C-O bond became longer,so as to achieve the purpose of the activation of CO2.