第一性原理分析CO_2在CaO(100)表面的吸附性能  

First-principles analyses of the adsorption properties of CO_2 molecule on CaO(100) surfaces

作　　者：李晓东[1,2] 刘成龙[3] 王长青[1] 马海霞[2] 

机构地区：[1]天水师范学院化学工程与技术学院,天水741000 [2]西北大学化工学院,西安710069 [3]昆明理工大学化学工程学院,昆明650224

出　　处：《原子与分子物理学报》2016年第5期893-900,共8页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(51063006);国家社会科学基金(13CMZ011);天水师范学院重点学科基金(TSA0818)

摘　　要：运用广义梯度密度泛函理论(GGA-PW91)结合周期平板模型方法,研究了CO_2分子分别在1×1×1和2×2×1CaO(100)超晶胞面最稳定位的吸附行为.结果表明:Ca O(100)表面的Osurf原子为CO_2分子的有效吸附位,能够和CO_2分子形成稳定吸附键C-Osurf,其吸附能为0.858 e V.在吸附前后C和Osurf原子的价电子组态分别由2s^(0.89)2p^(2.47)和2s^(1.84)2p^(4.99)变化为2s^(0.68)2p^(2.33)和2s^(1.90)2p^(5.17),而且在CO_2分子中的O2s原子与Surface层的Ca_(sub)4s原子间存在相互作用.考察了多个CO_2分子在2×2×1 Ca O(100)表面吸附时存在分子间相互排斥作用,发现当四个CO_2分子吸附到2×2×1CaO(100)超晶胞面时,排斥能为1.76e V,不利于CO_2分子的吸附.The process of stable adsorption of CO2 molecules on 1 × 1 × 1 and 2 × 2 × 1 CaO（ 100） surfaces were studied using a periodic slab model by PW91 of generalized gradient approximation（ GGA） within the framework of density functional theory.The results indicated that the Osurfatoms are the most stable adsorbed sites for CO2 on the CaO（ 100） surfaces,and the stable adsorbed bonds C-Osurfwere obtained with adsorption energies of 0.858 e V.The valence electrons configuration of C and Osurfatoms were changed from 2s0.892p2.47 and 2s1.842p4.99 to 2s0.682p2.33 and 2s1.902p5.17 during the adsorption system before and after adsorption,and that,the O2 s atoms of CO2 molecules and Casub4 s atoms of surfaces layer have the interactions.It was found that the repulsion energies is 1.76 eV when the four CO2 molecules adsorbed on the 2 × 2 × 1 CaO（ 100） super cell surfaces.It indicated that the effects of that repulsive interaction between multiple CO2 molecules adsorbed on the same surfaces are not conducive to the adsorption of CO2 molecules.

关 键 词：密度泛函理论 计算化学 二氧化碳捕集 吸附 排斥能 

分 类 号：TQ028.8[化学工程]