title: Specific oriented metal-organic framework membranes and their facet-tuned separation performance.
abstract: Modulating the crystal morphology, or the exposed crystal facets, of metal-organic frameworks (MOFs) expands their potential applications in catalysis, adsorption, and separation. In this article, by immobilizing the citrate modulators on Au nanoparticles and subsequently being fixed on solid copper hydroxide nanostrands, a well-intergrown and oriented HKUST-1 cube crystal membrane was formed at room temperature. In contrast, in the absence of Au nanoparticles, well-intergrown and oriented cuboctahedron and octahedron membranes were formed in water/ethanol and ethanol, respectively. The gas separation performances of these HKUST-1 membranes were tuned via their exposed facets with defined pore sizes. The HKUST-1 cube membrane with exposed {001} facets demonstrated the highest permeance but lowest gas binary separation factors, while the octahedron membrane with exposed {111} facets presented the highest separation factors but lowest permeance, since the window size of {111} facets is 0.46 nm which is smaller than 0.9 nm of {001} facets. Separation of 0.38 nm CO2 from 0.55 nm SF6 was realized by the HKUST-1 octahedron membrane. As a proof of concept, this will open a new way to design MOF-related separation membranes by facet controlling.
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, and ‡Cyrus Tang Center for Sensor Materials and Application, Department of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, P. R. China.
authors.forename: Yiyin
authors.initials: Y
authors.lastname: Mao
authors.forename: Binbin
authors.initials: B
authors.lastname: Su
authors.forename: Wei
authors.initials: W
authors.lastname: Cao
authors.forename: Junwei
authors.initials: J
authors.lastname: Li
authors.forename: Yulong
authors.initials: Y
authors.lastname: Ying
authors.forename: Wen
authors.initials: W
authors.lastname: Ying
authors.forename: Yajun
authors.initials: Y
authors.lastname: Hou
authors.forename: Luwei
authors.initials: L
authors.lastname: Sun
authors.forename: Xinsheng
authors.initials: X
authors.lastname: Peng
keywords: Au nanoparticles; facets-tuned; metal−organic frameworks; separation membranes; thin films