Adsorptive separation of ethylene or propylene from ethane or propane is an attractive strategy for its sustainable and inexpensive nature. Ag (I) grafted porous carbon adsorbents showed an excellent selective adsorption towards ethylene and propylene due to the π complexation. Starting from experimental evidences, Density Functional Theory (DFT) was used to understand the selective adsorption. The DFT computed adsorption energies of ethylene and propylene were 6.1 to 3.6 times higher than those of the saturated hydrocarbons depending on the pore size, which corroborated the higher experimental adsorbed amounts of alkenes. Thus, the DFT calculations highlighted the effect of the pore widths on the adsorption energy by providing an explanation based on both optimized geometries and molecular orbitals analysis. An overlap between d orbitals of Ag and π orbitals, centred on the carbons of unsaturated hydrocarbons, was found. This overlap was not found for the saturated hydrocarbons where, for pores with width around 5.23 Å, the d orbitals of silver overlap with the π orbital of the carbon atoms within the graphene plane placed in front of the Ag functionality, thereby rejecting the alkane. These theoretical findings confirm the empirical hypothesis of selective adsorption of unsaturated hydrocarbons by π−π complexation.

从乙烷或丙烷中吸附分离乙烯或丙烯是一种有吸引力的策略，因为它具有可持续且廉价的特性。Ag（I）接枝的多孔碳吸附剂由于π络合而表现出对乙烯和丙烯的优异选择性吸附。从实验证据开始，使用密度泛函理论（DFT）来了解选择性吸附。根据孔径的不同，DFT计算得出的乙烯和丙烯的吸附能比饱和烃的吸附能高6.1至3.6倍，这证实了烯烃的实验吸附量更高。因此，DFT计算通过提供基于优化的几何结构和分子轨道分析的解释，突出了孔宽度对吸附能量的影响。之间的重叠发现了以不饱和烃的碳为中心的Ag和π轨道的d轨道。对于饱和烃，未发现这种重叠，对于宽度为5.23Å的孔，银的d轨道与位于Ag官能团前面的石墨烯平面内的碳原子的π轨道重叠，从而排斥烷烃。这些理论发现证实了通过π-π络合选择性吸附不饱和烃的经验假设。