摘要
The design and synthesis of stable metal–organic frameworks(MOFs)have been a core obstacle in the widespread application of these functional crystalline porous materials,because of the stability limitations of MOFs under harsh operating conditions.Herein,a highly stable microporous MOF based on the Fe_(3)O cluster(PCN-678)has been synthesized using a tetracarboxylate ligand.Utilizing symmetry reduced tetratopic carboxylate ligand,a mesoporous MOF(PCN-668)could be obtained in which nanoscale cage-like building units and one-dimensional(1D)channels coexist.The neighboring cages were mutual diastereomers in PCN-668 due to the further reduction of the Cs symmetry of the free ligand to C1 symmetry after self-assembly.Furthermore,the acid stability of this mesoporous MOF was improved via postsynthetic metal exchange to chromium(PCN-668-Cr).The PCN-668-Cr exhibited very high stability in both acidic and basic aqueous solutions(pH=1–11).Additionally,the mesoporous MOF showed a high total gravimetric methane uptake(∼500 cm^(3) g^(−1) at 100 bar),while the microporous MOF showed a high volumetric methane storage capacity of 147 cm3 cm−3 at room temperature.
基金
supported by the Center for Gas Separations,an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences(no.DESC0001015)
Structural analyses were supported by the Robert A.Welch Foundation through a Welch Endowed Chair to H.-C.Z.(A-0030)
The National Science Foundation Graduate Research Fellowship(DGE:1252521)is gratefully acknowledged.The authors also acknowledge the financial support of the U.S.Department of Energy Office of Fossil Energy,National Energy Technology Laboratory(no.DE-FE0026472)
and National Science Foundation Small Business Innovation Research(NSFSBIR)under grant no.(1632486)
the financial support of the Strategic Priority Research Program of the Chinese Academy of Sciences(no.XDB20000000)
National Nature Science Foundation of China(no.21871266),CAS(no.QYZDY-SSWSLH025),and Youth Innovation Promotion Association CAS.
