CO_2和CO分子在五边形石墨烯表面的吸附行为

The Adsorption Behavior of CO_2 and CO on Penta-Graphene

基于密度泛函理论的第一性原理计算方法,研究了2种常见气体分子CO_2和CO在五边形石墨烯表面的吸附行为.根据五边形石墨烯的结构特点以及CO_2和CO的分子形态,CO_2共有4种吸附方式,而CO则有6种吸附方式.通过计算吸附能、电荷转移、吸附距离、能带间隙、电荷密度、态密度、分波态密度等指标,探究这2种气体分子不同方式的吸附情况.结果表明:气体分子的不同吸附方式对吸附行为有明显影响; CO_2与CO在基底上最大吸附能的绝对值分别为0.071 3、0.086 7 e V,说明CO比CO_2有更好的吸附效果;由于气体分子与基底之间未能形成化学键,CO_2和CO在五边形石墨烯表面的吸附是比较弱的物理吸附.

First-principles calculations based on density functional theory are utilized to study the adsorption behavior of CO2 and CO on penta-graphene( PG) surface. According to the structure of PG and the molecular formation of CO2 and CO,there are four adsorption orientations for CO2 and six adsorption orientations for CO. By calculating the adsorption energy,charge transfer,adsorption distance,band gap,electron density,density of states and the partial density of states,the adsorption behavior of CO2 and CO on PG are investigated. The results show that: different adsorption orientations of gas molecules have obvious effects on the adsorption behavior;the absolute adsorption energies of CO2 and CO on the substrate were 0.071 3 eV and 0.086 7 eV respectively,indicating that CO had better adsorption effect than CO2;due to failing to form chemical bonds between the gas molecules and the substrate,the adsorption of CO2 and CO on the PG surface is relatively weak physical adsorption.