In cluster-based MOF materials,although clusters with open metal sites(OMSs)play a critical role in separation processes,excessively strong OMSs can lead to significant co-adsorption with the counterpart gases and res...In cluster-based MOF materials,although clusters with open metal sites(OMSs)play a critical role in separation processes,excessively strong OMSs can lead to significant co-adsorption with the counterpart gases and result in reduced selectivity.Coordinated water molecules can not only result in atomic-level differences in pore size but also significantly affect the binding forces between the host frameworks and vip molecules.Herein,we report a methyl-modified heptanuclear cluster-based MOF,Ni_(7)Me,constructed from inexpensive organic linkers under pure water conditions.Two vip-free materials,Ni_(7)Me-80(with coordinated water)and Ni_(7)Me-200(with OMSs),were synthesized to investigate the separation properties and mechanisms for C_(2)H_(2)/C_(2)H_(4) and C_(3)H_(6)/C_(3)H_(8) mixtures.Dynamic breakthrough tests showed that both Ni_(7)Me-80 and Ni_(7)Me-200 could achieve clean separation of binary C_(2)H_(2)/C_(2)H_(4) mixtures(5/95 v/v),yielding high-purity C_(2)H_(4)(>99.9%).Grand canonical Monte Carlo(GCMC)simulations revealed that the enhanced adsorption and separation performance of Ni_(7)Me-200,compared to Ni_(7)Me-80,is primarily due to differences in the interaction forces between C_(2) molecules and the framework,independent of the OMSs.Notably,Ni_(7)Me-80 exhibited thermodynamically driven adsorption for C_(3)H_(6),while showing kinetic behaviour for C_(3)H_(8) adsorption.This unique property enabled effective separation of C_(3)H_(6) and C_(3)H_(8),as demonstrated by dynamic permeation tests.Stability tests further showed that Ni_(7)Me has exceptional air and boiling water stability.展开更多
基金the Natural Science Foundation of Ningbo(2022J101)This work was carried out with the support of the Shanghai Synchrotron Radiation Facility,instrument BL17B.
文摘In cluster-based MOF materials,although clusters with open metal sites(OMSs)play a critical role in separation processes,excessively strong OMSs can lead to significant co-adsorption with the counterpart gases and result in reduced selectivity.Coordinated water molecules can not only result in atomic-level differences in pore size but also significantly affect the binding forces between the host frameworks and vip molecules.Herein,we report a methyl-modified heptanuclear cluster-based MOF,Ni_(7)Me,constructed from inexpensive organic linkers under pure water conditions.Two vip-free materials,Ni_(7)Me-80(with coordinated water)and Ni_(7)Me-200(with OMSs),were synthesized to investigate the separation properties and mechanisms for C_(2)H_(2)/C_(2)H_(4) and C_(3)H_(6)/C_(3)H_(8) mixtures.Dynamic breakthrough tests showed that both Ni_(7)Me-80 and Ni_(7)Me-200 could achieve clean separation of binary C_(2)H_(2)/C_(2)H_(4) mixtures(5/95 v/v),yielding high-purity C_(2)H_(4)(>99.9%).Grand canonical Monte Carlo(GCMC)simulations revealed that the enhanced adsorption and separation performance of Ni_(7)Me-200,compared to Ni_(7)Me-80,is primarily due to differences in the interaction forces between C_(2) molecules and the framework,independent of the OMSs.Notably,Ni_(7)Me-80 exhibited thermodynamically driven adsorption for C_(3)H_(6),while showing kinetic behaviour for C_(3)H_(8) adsorption.This unique property enabled effective separation of C_(3)H_(6) and C_(3)H_(8),as demonstrated by dynamic permeation tests.Stability tests further showed that Ni_(7)Me has exceptional air and boiling water stability.
