A promising controllable CO_(2)capture and separation materials for CO_(2)/CH_(4)/H_(2)under electric field  

作　　者：Chaozheng He Houyong Yang Ling Fu 

机构地区：[1]Shaanxi Key Laboratory of Optoelectronic Functional Materials and Devices,Institute of Environment and Energy Catalysis,School of Materials Science and Chemical Engineering,Xi'an Technological University,Xi'an 710021,China [2]College of Resources and Environmental Engineering,Tianshui Normal University,Tianshui 741001,China

出　　处：《Chinese Chemical Letters》2023年第5期587-593,共7页中国化学快报（英文版）

基　　金：funded by the National Natural Science Foundation of China(No.21603109);the Henan Joint Fund of the National Natural Science Foundation of China(No.U1404216);the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.20JK0676)。

摘　　要：As the greenhouse effect concerns increases,the development of new materials for the efficient capture and separation of CO_(2)gas from gas mixtures has become a matter of urgency.In this study,we performed density functional theory(DFT)calculations to investigate the adsorption and separation behavior of CO_(2)/CH_(4)/H_(2)on the surface of two-dimensional(2D)Al_(2)C materials under positive/negative applied electric fields.In the absence of an electric field CO_(2)is weakly physisorbed on the Al_(2)C surface,but with the application of an applied electric field,the adsorption state of CO_(2)gradually changes from physical to chemisorption(adsorption energy changes from-0.29 e V to-3.61 e V),while the negative electric field has little effect on the adsorption of CO_(2).We conclude that the C=O bond in adsorbed CO_(2)can be activated under an external electric field(maximum activation of 15%under an external electric field of 0-0.005 a.u.).Only in the presence of an applied electric field of 0.0033 a.u.and temperatures above525 K/675 K can the adsorption/separation reaction of CO_(2)single adsorption and CO_(2)/CH_(4)/H_(2)mixture be spontaneous.The adsorption/desorption of CO_(2)on Al_(2)C nanosheet in an electric field of 0.003-0.0033 a.u.is all exothermic,which can be easily controlled by switching on/off the electric field without any energy barriers.The capacity of Al_(2)C to capture CO_(2)per unit electric field decreases with increasing CO_(2)concentration,but still has efficient gas separation properties for CO_(2)/CH_(4)/H_(2).Our theoretical results could provide guidance for designing high-capacity and high-selectivity CO_(2)capture materials.

关 键 词：CO_(2)capture Electric-field controlled CO_(2)/CH_(4)/H_(2)mixture sequestration Density functional theory Two-dimensional materials 

分 类 号：X701[环境科学与工程—环境工程] TB34[一般工业技术—材料科学与工程] O647.3[理学—物理化学]