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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.
Through the first principles of density functional theory, the adsorption behavior of CO2 molecules on the TiO2- and SrO- sites of SrTiO3 (100) surface was simulated. The structure parameters and the surface adsorption energy of CO2 under several different adsorption models were obtained. , And then the adsorption mechanism and the structural stability are studied.The results show that the adsorption structure is stable when the C atom of CO2 is adsorbed on the SrO- and TiO2-site oxygen atoms of SrTiO3 (100), especially C, O The atomic co-adsorption is most stable at the TiO2-site and the rest of the adsorption model is not stable. The Mulliken number and density of states of the adsorbed stable model show that the adsorption of CO2 molecules on the SrTiO3 (100) surface is mainly due to SrTiO3 (100) Surface electrons to transition to CO2 molecules, CO2 molecules get electrons to form a curved CO2 - anion structure, accompanied by CO bond elongation, so as to achieve the purpose of adsorption activated carbon dioxide.