电场作用下S修饰C24N24从CO2/N2混合气体中选择性吸附

在燃烧后气体中选择性捕获CO2，对减缓因CO2浓度过高引发的环境问题具有十分重要的意义。本文采用第一性原理计算的方法，研究了外加电场作用下S修饰C24N24富勒烯对CO2的选择性吸附性能。首先研究了S@C24N24的结构和性质，发现其具有良好的稳定性。其次，研究了无电场时S修饰C24N24富勒烯对CO2的吸附行为，发现其吸附为弱的物理吸附。另外，进一步研究了外加电场作用下S@C24N24对CO2的吸附行为。结果表明，结合距离（CO2与S）和CO2的键角（O=C=O）随电场的增大而减小；当电场增加到0.018 au时，物理吸附转变为化学吸附。关闭电场时，化学吸附又转化为物理吸附。此外，即使在相同的电场条件下，S修饰C24N24富勒烯对N2的吸附也为弱的物理吸附。这表明，通过控制外加电场的开/关，S@C24N24可以从CO2/N2混合气体中选择性捕获/释放CO2，可作为选择性捕获CO2的优良候选材料。

First-principles calculation of the selective adsorption of CO2from CO2/N2 gas mixture by S-decorated C24N24under

The selective capture of CO2 in the burned gas is of great significance to alleviating environmental problems caused by excessive CO2 concentration. In this paper, first-principles calculations are carried out to study the selective adsorption performance of S-decorated C24N24 fullerenes (S@C24N24) for CO2 under external electric field. The structure and properties of S@C24N24 are calculated and the results show that S@C24N24 has good stability. The adsorption behavior of CO2 on S@C24N24 is also studied without electric field, and it is found that the adsorption belongs to weak physical adsorption. After that, the adsorption behavior of CO2 over S@C24N24 under the external electric field is further studied. The results show that the bonding distance (CO2 and S) and the bonding angle of CO2 (O=C=O) decrease with the increase of the electric field. The physical adsorption changes to chemical adsorption when the electric fields increase to 0.018 au, and then the chemical adsorption converts to physical adsorption by shutting down the electric field. In addition, the adsorption of N2 on S@C24N24 is weak physical adsorption even under the same electric field. These results show that by controlling the on/off of the applied electric field, S@C24N24 can selectively capture/release CO2 from CO2/N2 mixed gas, and can be used as an excellent candidate material for selective CO2 capture.