Confined electric field in nano-sized channels of ionic porous framework towards unique adsorption selectivity  

作　　者：Congyan Liu Xueyao Zhou Fei Ye Bin Jiang Bo Liu 

机构地区：[1]School of Chemistry and Materials Science,University of Science and Technology of China,Hefei 230026,China

出　　处：《Chinese Chemical Letters》2025年第2期437-441,共5页中国化学快报(英文版)

基　　金：support from the Chinese Academy of Sciences and University of Science and Technology of China,National Key Research and Development Program of China(No.2021YFA1500402);National Natural Science Foundation of China(Nos.21571167,51502282 and 22075266);Fundamental Research Funds for the Central Universities(Nos.WK2060190053 and WK2060190100)。

摘　　要：Efficient selective adsorption and separation using porous frameworks are critical in many industrial processes,where adsorption energy and dynamic diffusion rate are predominant factors governing selectivity.They are highly susceptible to framework charge,which plays a significant role in selective adsorption.Currently,ionic porous frameworks can be divided into two types.One of them is composed of a charged backbone and counter ions.The framework with zwitterionic channels is another type.It is composed of regular and alternating arrangements of cationic and anionic building units.Herein,we report a hydrogen-bonded ionic framework(HIF)of{(CN_(3)H_(6))_(2)[Ti(μ_(2)-O)(SO_(4))_(2)]}_nwith 1D channel exhibits unique adsorption selectivity for Ar against N_(2)and CO_(2).Density functional theory(DFT)results suggest that CO_(2)cannot be adsorbed by HIF at the experimental temperature due to a positive adsorption free energy.In addition,due to a relatively large diffusion barrier at 77 K,N_(2)molecules hardly diffuse in HIF channels,while Ar has a negligible diffusion barrier.The unique net positively-charged space in the channel is the key to the unusual phenomena,based on DFT simulations and structural analysis.The findings in this work proposes the new adsorption mechanism and provides unique perspective for special separation applications,such as isotope and noble gasses separations.

关 键 词：Adsorption SELECTIVITY Channel Positive electric field GUANIDINIUM 

分 类 号：O647.3[理学—物理化学]