电场作用下P掺杂硅烯选择性吸附CH_4的第一性原理计算

在煤层气中选择性吸附和捕捉甲烷分子,对提高煤矿安全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P掺杂硅烯对甲烷分子的选择性吸附性能.结果表明:正电场作用下,P掺杂硅烯与甲烷分子之间产生较强的化学吸附,能够快速捕获甲烷分子.当关闭外加电场时,P掺杂硅烯与甲烷分子之间则为微弱的物理吸附,甲烷分子很容易实现脱附.同时还发现,外加电场作用下,P掺杂硅烯与氮气、氧气及水之间的吸附均属于物理吸附,表明P掺杂硅烯可以在这些混合气体中实现甲烷气体的选择性吸附. P掺杂硅烯有望成为选择性好的甲烷传感、捕获新材料.

First-principles calculation of the selective adsorption of CH4 by P-doped silicene under electric field

Selective adsorption and capture of methane molecules in coalbed is of great significance for improving coal mine safety. The first-principles calculation method was used to study the selective adsorption performance of P-doped silicene for methane molecules under the external electric field. The results showed that under the positive electric field, strong chemical adsorption occurs between P-doped silicene and methane molecules, which can quickly capture methane molecules. When the external electric field is turned off, there is a weak physical adsorption between the P-doped silicene and the methane molecule, and the methane molecule is easily desorbed. At the same time, it was also found that the adsorption between P-doped silicene and nitrogen, oxygen or water is physical adsorption under the action of an external electric field, indicating that P-doped silicene can achieve selective adsorption of methane gas in these mixed gases. P-doped silicene is expected to be a new material with high selectivity for methane sensing and capturing.