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Ordered and flexible porous frameworks with solution processability are highly desirable to fabricate continuous and large‐scale membranes for the efficient gas separation. Herein, the first microporous hydrogen‐bonded organic framework (HOF) membrane has been fabricated by an optimized solution‐processing technique. The framework exhibits the superior stability because of the abundant hydrogen bonds and strong π–π interactions. Thanks to the flexible HOF structure, the membrane possesses the unprecedented pressure‐responsive H2/N2 separation performance. Furthermore, the scratched membrane can be healed by the treatment of solvent vapor, achieving the recovery of separation performance. [ABSTRACT FROM AUTHOR]

Innentitelbild: Fabrication of a Hydrogen-Bonded Organic Framework Membrane through Solution Processing for Pressure-Regulated Gas Separation (Angew. B Geordnete und flexible b poröse Gerüste, die in Lösung verarbeitbar sind, sind wünschenswert, um kontinuierliche und großtechnische Membranen für die effiziente Gastrennung aufzubauen. In ihrer Zuschrift auf S. 3868 stellen D. Sun, Z. Kang und Mitarbeiter lösungsbasiert die erste Membran her, die aus einem Wasserstoffbrücken-gebundenen organischen Gerüst aufgebaut ist. [Extracted from the article]

By the combination of the two-dimensional graphene oxide with stable covalent organic frameworks, composite membranes are fabricated through vacuum filtration with the high performance for H 2 /CO 2 separation. • A series of TpPa COFs are synthesized by facile mechanical grinding. • TpPa COFs are fabricated into membranes by the assistance of GO. • The membranes are prepared via a universally applicable vacuum filtration method. • The composite membranes exhibit high performance of H 2 /CO 2 separation. Covalent organic frameworks (COFs) are getting more attention by virtue of their intriguing architectures and properties. However, the obstacle for fabricating sequential COF-based membranes for gas separation has become a challenge. In this research, a series of TpPa COFs are successfully synthesized by a facile approach of mechanical grinding. To alleviate the dilemma of membrane formation, we introduce graphene oxide (GO) that owns two-dimensional flexibility to sufficiently assist the COFs to form lamellar membranes. By directly mixing the solutions of GO and COFs, robust and continue COFs/GO composite membranes are prepared without defects via the vacuum filtration. The thickness and the H 2 /CO 2 selectivity of the membranes can be regulated by increasing the amount of GO. The optimal membrane obtained with a GO/COFs ratio of 33.33% (TpPa-1-30/GO-10) exhibits the H 2 /CO 2 selectivity of 25.57 with H 2 permeance of 1.067 × 10−6 mol·m−2·s−1·Pa−1. This work provides a simple, universal and applicable approach to prepare COF-based composite membranes for separation. [ABSTRACT FROM AUTHOR]

Mixed matrix membranes (MMMs) based on metal-organic frameworks (MOFs) have proven to have high separation performance, which has great potential in separation applications. However, unsatisfactory hydrothermal stability is the Achilles' heel of MOFs in practical applications, which seriously hinders the development of MOF based MMMs. Under the advantage of crystal anisotropy, a morphology regulation strategy without post-treatment is presented for the first time to efficiently improve the stability of MOF fillers in aqueous solution. Contrary to the regular dodecahedron ZIF-67 crystals, the [211] oriented ZIF-67 nanosheets (NS) can maintain an ordered microporous framework integrally in the aqueous solution of membrane preparation. The exposed [211] crystal face exhibits enhanced stability due to a lower proportion of Co–N bond and higher surface atomic density. The flake morphology of ZIF-67 with economic incorporation (5.0 wt %) offers the MMMs significantly enhanced CO 2 permeability of 139.4 barrer and CO 2 /N 2 ideal selectivity of 73.2, improved by 50.7% and 76.0% compared with the pristine polymer membrane. This strategy provides a new idea for improving the hydrothermal stability of MOF materials and extends their separation applications under aqueous conditions. Oriented MOF nanosheets with higher hydrothermal stability than anisotropic crystals are applied to construct the mixed matrix membrane in aqueous solution, which exhibit highly improved CO 2 /N 2 separation performance compared with the pristine polymer membrane. Image 1 • The hydrothermal stability of ZIF-67 is improved by morphology regulation. • The MMMs are fabricated with the low corporation of ZIF-67 in aqueous solution. • Significantly improved gas separation performance is achieved by the MMMs. [ABSTRACT FROM AUTHOR]