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Highlights: [•] Pure and dense ZIF-90 membranes with shape-selectivity were prepared. [•] With APTES modification, the membrane permselectivity increases. [•] For the separation of CO2/CH4 mixture, a good CO2/CH4 selectivity of 4.7 is obtained. [ABSTRACT FROM AUTHOR]

Inspired by the bio-adhesive ability of the marine mussel, highly hydrogen permselective ZIF-8 membranes were prepared on polydopamine functionalized stainless-steel-nets (SSNs). With polydopamine functionalization of SSNs under mild conditions, the nucleation and growth of well-intergrown ZIF-8 membranes were promoted through the formation of strong non-covalent and covalent bonds, which was helpful to enhance the membrane's separation selectivity while maintaining high permeance. For binary mixtures at 100 °C and 1 bar, the mixture separation factors of H[sub 2]-CO[sub 2], H[sub 2]-N[sub 2], H[sub 2]-CH[sub 4] and H[sub 2]-C[sub 3]H[sub 8], were found to be 8.1, 15.0, 23.2 and 329.7, which by far exceed the corresponding Knudsen coefficients and those of the as-reported ZIF-8 membranes. The ZIF-8 membranes also displayed high permeances, with the H[sub 2] permeance higher than 2.1 x 10[sup -5] mol m[sup -2]s[sup -1] Pa[sup -1] due to the high void volume of the SSNs. [ABSTRACT FROM AUTHOR]

Abstract: In a detailed study, the influence of the most relevant synthesis parameters on the crystallization of LTA-type AlPO4 using Kryptofix 222 (K222) as structure directing agent (SDA) was investigated with the aim to develop a reliable and reproducible strategy for the preparation of large and well-shaped crystals. Only with sufficient mixing time for the aluminophosphate gel before adding the SDAs, well-shaped cubic and large LTA-type AlPO4 crystals could be obtained. With increasing water content in the starting gel, the crystal size became larger and the cubic crystals displayed less truncated. Hydrofluoric acid was found to be a more efficient mineralizer to form large and well-shaped cubic crystals than ammonium fluoride. When Al(OH)3 was used instead of our standard aluminium source Al2O3, the crystal size was not influenced. When Al[OCH(CH3)2]3 was the aluminium source, the size of the LTA-type AlPO4 crystals decreased much, probably since a larger number of nuclei was formed upon hydrolysis of Al[OCH(CH3)2]3. When Al2(SO4)3 was used as aluminium source, no LTA-type AlPO4 crystals could be obtained. With increasing substitution of aluminium by gallium, the crystals size increased and the crystal surface became rough. All diffraction patterns of mixed (Al+Ga)PO4 crystals were characteristic of the LTA framework. The same Ga/Al and (Al+Ga)/P ratio of the synthesis gel was also found in the (Al+Ga)PO4 crystals. Low temperature in combination with long synthesis time was found to be beneficial for the preparation of large and well-shaped AlPO4 crystals. [Copyright &y& Elsevier]

Abstract: Thin NaA zeolite membranes, with uniform and small crystals, were prepared on the tubular α-Al2O3 support by adding a small amount of tetramethylammonium hydroxide (TMAOH) in the clear synthesis solution. The as-synthesized NaA zeolite membranes were characterized by XRD and SEM. The permeation properties of the membranes were evaluated by pervaporation and gas permeation. The effects of TMAOH amount on membrane formation and permeation properties were investigated. By addition of suitable amount of TMAOH in the clear synthesis solution, the crystals size of NaA zeolite could be remarkably reduced from about 10μm to 3–4μm, and the membrane thickness correspondingly reduced from about 16μm to 5μm. The thinner membrane prepared by adding TMAOH in the clear synthesis solution, with uniform and small crystal, displayed higher perm-selective properties than that without adding TMAOH. For the as-synthesized NaA zeolite membrane prepared with adding suitable amount of TMAOH (x =1), the separation factor (water/isopropanol) was 4700 and the flux was 1.67kg/(m2 h), which were higher than that without adding TMAOH of 339 and 1.08kg/(m2 h), respectively. The ideal separation factor of H2/N2 was 6.60, higher than that without adding TMAOH of 3.41. [Copyright &y& Elsevier]

Abstract: Uniform and dense NaA zeolite membranes were prepared on the α-Al2O3 support by electrophoretic technique. The membrane morphology and membrane thickness were investigated by XRD, SEM and pervaporation properties for dehydration of 95wt.% isopropanol/water mixture at 343K, respectively. Under the action of the applied electric field, the negatively charged zeolite particles could migrate to the support surface homogenously and rapidly, forming uniform and dense membranes in a short time. High quality NaA zeolite membrane, with a separation factor (water/isopropanol) of 3281 and a flux of 1.24kg/m2 h, could be prepared by electrophoretic technique with the electrical potential of 1V. The formation mechanism of zeolite membrane in the electric field is discussed. [Copyright &y& Elsevier]

A-type zeolite membranes were prepared on the nonporous metal supports by using electrophoretic technique. The as-synthesized membranes were characterized by XRD and SEM. The effect of the applied potential on the formation of the A-type zeolite membrane was investigated, and the formation mechanism of zeolite membrane in the electric field was discussed. The results showed that the negative charged zeolite particles could migrate to the anode metal surface homogenously and rapidly under the action of the applied electric field, consequently formed uniform and dense membranes in short time. The applied potential had great effect on the membrane formation, and more uniform and denser zeolite membranes were prepared on the non- porous metal supports with 1 V potential. [ABSTRACT FROM AUTHOR]

A thin and compact mixed matrix membrane containing CAU-1-NH2 and the poly(methyl methacrylate) polymer has been originally synthesized. The as-prepared membrane exhibits high permeability of H2 and excellent H2/CO2 selectivity. [ABSTRACT FROM AUTHOR]

A neutral framework cation-free hydrophobic ITQ-29 molecular sieve membrane with hydrogen selectivity was prepared on porous α-Al2O3supports by using Kryptofix 222 as organic structure directing agent through secondary growth method. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) materials with high chemical stability have attracted intensive interest in membrane design for the separation of organic solvents. As a novel 2D material, polymeric fullerenes (C60)∞ with distinctive properties are very promising for the development of innovative membranes. In this work, we report the construction of a 2D (C60)∞ nanosheet membrane for organic solvent separation. The pathways of the (C60)∞ nanosheet membrane are constructed by sub‐1‐nm lateral channels and nanoscale in‐plane pores created by the depolymerization of the (C60)∞ nanosheets. Attributing to ordered and shortened transport pathways, the ultrathin porous (C60)∞ membrane is superior in organic solvent separation. The hexane, acetone, and methanol fluxes are up to 1146.3±53, 900.4±41, and 879.5±42 kg ⋅ m−2 ⋅ h−1, respectively, which are up to 130 times higher than those of the state‐of‐the‐art membranes with similar dye rejection. Our findings demonstrate the prospect of 2D (C60)∞ as a promising nanofiltration membrane in the separation of organic solvents from macromolecular compounds such as dyes, drugs, hormones, etc. [ABSTRACT FROM AUTHOR]

Hydrogen has been regarded as the most promising clean and renewable energy. Beside the production of the hydrogen, the separation of hydrogen is also an import issue before it can be used in fuel cells. Membrane-based separation technologies have gained considerable attentions due to its high efficiency and low energy consumption. Zeolite imidazolate framework (ZIF) membranes have drawn intense interest due to their zeolite-like properties such as permanent porosity, uniform pore size and exceptional thermal and chemical stability. It is rather challenged to prepare well-intergrown Co-based zeolitic imidazolate frameworks (ZIFs) membranes on porous α-Al 2 O 3 tubes since Co-based ZIFs prefer to form crystals in the synthesis solution rather than grow as membrane layer on the support surface. In this work, we report the preparation of high-quality ZIF-9 membrane with high H 2 /CO 2 selectivity and excellent thermal stability by using 3-aminopropyltriethoxysilane (APTES) as a covalent linker to modify the α-Al 2 O 3 tube. Due to the formation of covalent bonds between APTES and ZIF-9, ZIF-9 nutrients are bound to the support surface, thus promoting the growth of dense and phase-pure ZIF-9 membrane with a thin thickness of about 4.0 μm. The gas separation performances of the ZIF-9 membrane were evaluated by single gas permeation and mixture gas separation of H 2 /CO 2 , H 2 /N 2 and H 2 /CH 4 , respectively. The mixture separation factors of H 2 /CO 2 , H 2 /CH 4 , and H 2 /N 2 of the ZIF-9 membrane are 21.5, 8.2 and 14.7, respectively, which by far exceeds corresponding Knudsen coefficients. Moreover, the as-prepared ZIF-9 membrane exhibits excellent stability at a relatively broad range of operating temperature, which is beneficial for the industrial application of hydrogen separation or further membrane reactor. Image 1 • A well-intergrown ZIF-9 membrane is prepared on Al 2 O 3 tube for hydrogen separation. • Covalent modification is helpful for formation of well-intergrown ZIF-9 membranes. • The ZIF-9 molecular sieving membranes display high hydrogen permselectivity. [ABSTRACT FROM AUTHOR]

A facile self-templated carbonization strategy is developed for fabrication of a bifunctional electrocatalyst with uniform distribution of F, N heteroatoms, mesoporous channels and abundant edge-defect by direct pyrolysis of F, N -containing covalent organic framework (F-COF) precursor. The designed catalyst exhibits excellent bifunctional catalytic activity with a small OER-ORR potential gap of 0.79 V. The assembled ZAB delivers a high peak density of 206.3 mW cm−2 and good cyclic stability. [Display omitted] • F, N co-doped porous carbon (F-NPC) was facile prepared by in situ pyrolysis of fluoric COF precursor. • Experiments combined with theoretical calculation confirmed the significant contribution of F in boosting the catalytic reactivity. • The designed F-NPC catalyst shows superior ORR and OER activity. • The assembled ZAB using F-NPC catalyst displays high peak power density and excellent durability. The construction of heteroatom-doped metal-free carbon catalysts with bifunctional catalytic activity for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is highly desired for Zn-air batteries, but remains a great challenge owing to the sluggish kinetics of OER and ORR. Herein, a self-sacrificing template engineering strategy was employed to fabricate fluorine (F), nitrogen (N) co-doped porous carbon (F-NPC) catalyst by direct pyrolysis of F, N containing covalent organic framework (F-COF). The predesigned F and N elements were integrated into the skeletons of COF precursor, thus achieving uniformly distributed heteroatom active sites. The introduction of F is beneficial for the formation of edge-defects, contributing to the enhancement of the electrocatalytic activity. Attributing to the porous feature, abundant defect sites induced by F doping, as well as the strong synergistic effect between N and F atoms to afford a high intrinsic catalytic activity, the resulting F-NPC catalyst exhibits excellent bifunctional catalytic activities for both ORR and OER in alkaline mediums. Furthermore, the assembled Zn-air battery with F-NPC catalyst shows a high peak power density of 206.3 mW cm−2 and great stability, surpassing the commercial Pt/C + RuO 2 catalysts. [ABSTRACT FROM AUTHOR]

Two kinds of diamine molecules, including 1, 4-cyclohyxanediamine (CDA) and p -phenylenediamine (pPDA), were used as cross-linking for modification of graphene oxide (GO) nanosheets to prepare three-dimensional graphene oxide framework (GOF). Thereafter, graphene oxide composite membranes (GOCMs) were prepared on the polydopamine (PDA) modified α-Al 2 O 3 tubes via vacuum filtration of GOF suspension. The separation performance of the GOCMs was tested for seawater desalination by pervaporation. The cross-linking modification, membrane thickness, operation temperature, feed concentration and PDA modification of α-Al 2 O 3 tube have great effect on the separation performance of the GOCMs. Attributing to the enhancement of d-spacing and surface hydrophilicity after CDA modification, the CDA-based GOCM (CDA-GOCM) shows a higher water flux (20.1 kg m −2  h −1 with ion rejection of 99.9%) for desalination of 3.5 wt% seawater at 90 °C, which is higher than that of GO membrane (11.4 kg m −2  h −1 with ion rejection of 99.9%). However, since the hydrophilicity of the GO markedly decreases after pPDA modification, the pPDA-based GOCM (pPDA-GOCM) show a lower water flux (10.7 kg m −2  h −1 with ion rejection of 99.8%) at 90 °C. Further, the CDA-GOCM prepared on the PDA-modified α-Al 2 O 3 tubes displays high stability for desalination of 3.5 wt% seawater. [ABSTRACT FROM AUTHOR]

Methanol formation from CO2 hydrogenation attracts great attention in view of utilization of carbon resources. However, CO2 transformation to methanol is challenging because of the thermodynamic equilibrium restriction and water‐caused catalyst deactivation. It is desired, therefore, to develop highly active, selective and stable catalysts for CO2 hydrogenation to methanol. Herein, we propose a novel tandem catalyst composed of Cu−ZnO−Al2O3−ZrO2 (CZAZ) and Cu−MOR for highly selective conversion of CO2 to methanol. During CO2 hydrogenation by the CZAZ catalyst, the by‐product methane is continuously transformed to methanol through reaction with water via the Cu−MOR catalyst, thus enhancing CO2 conversion and methanol selectivity. Under mild reaction conditions (200 °C and 3.0 MPa), high CO2 conversion (40.7 %) and methanol selectivity (97.6 %) are achieved, outperforming state‐of‐the‐art CO2 hydrogenation catalysts. Further, water‐caused deactivation of the catalyst through aggregation and densification is suppressed owing to water consumption via methane oxidation to methanol, validating a high CZAZ/Cu−MOR tandem catalyst stability. [ABSTRACT FROM AUTHOR]

Membrane separation is an energy‐efficient and environmentally friendly process. Two‐dimensional (2D) molecular sieving membranes featuring unique nanopores and low transport resistance have the potential to achieve highly permeable and selective mixture separation with low energy consumption. High‐aspect‐ratio zeolite nanosheets with intrinsic molecular‐sieving pores perpendicular to the layers are desirable building blocks for fabricating high‐performance 2D zeolite membrane. However, a wider application of 2D zeolitic membranes is restricted by the limited number of recognized zeolite nanosheets. Herein, we report a swollen layered zeolite, ECNU‐28, with SZR topology and eight‐member ring (8‐MR, 3.0 Å×4.8 Å) pores normal to the nanosheets. It can be easily exfoliated to construct 2D membrane, which shows a high hydrogen selectivity up to 130 from natural gas and is promising for hydrogen purification and greenhouse gas capture. [ABSTRACT FROM AUTHOR]

In this study, dense and phase-pure zeolite FAU membrane has been prepared on α-Al 2 O 3 tube using a seeding-free synthesis strategy. 3-aminopropyltriethoxysilane (APTES) acts as a molecular linker for anchoring the FAU precursors onto the support surface to promote the nucleation and the formation of a thin, well intergrown zeolite FAU membrane. The obtained membranes are employed for desalination of seawater by pervaporation. With the increase of the synthesis time from 12 h to 24 h at 75 °C, the water fluxes of the zeolite FAU membranes reduce from 4.22 kg m −2 h −1 to 3.42 kg m −2 h −1 at 75 °C due to the increase of the thickness of the zeolite FAU membranes, while the ions rejections increase from 99% to 99.9%. For the zeolite FAU membrane which was prepared at 75 °C for 20 h, with increasing the feed temperature from 30 °C to 90 °C, the water fluxes increase from 0.96 kg m −2 h −1 to 5.64 kg m −2 h −1 , and all the ions rejections of the zeolite FAU membrane are above 99.8%. Note that the zeolite FAU membranes show high separation performances for seawater desalination, even for desalination of 10 wt% seawater, the developed zeolite FAU membranes are very promising in seawater desalination. [ABSTRACT FROM AUTHOR]

In the present work, we reported the preparation of graphene oxide framework (GOF) membrane through vacuum filtration of GOF suspension for seawater desalination. Firstly, 1, 4-phenylene diisocyanate (PDI) was selected as cross-linking for covalent modification of GO nanosheets to prepare three-dimensional GOF. Secondly, micron-thickness GOF membrane was prepared on the PDI-modified α-Al 2 O 3 tube through vacuum filtration of GOF suspension. The developed GOF membrane was evaluated for seawater desalination by pervaporation. Attributing to a three-dimensional structure, the resistance of the mass transferring through GOF membrane can be reduced, thus the water flux of the GOF membranes can be increased significantly. For an 18 μm thickness of GOF membrane at 90 °C, the water flux is 11.4 kg·m − 2 ·h − 1 and ion rejection is over 99.9% for desalination of 3.5 wt.% seawater. Further, the GOF membrane also displays high stability for seawater desalination. This high separation performance combined with high stability and facile fabrication road of the GOF membrane suggests that the developed GOF membrane is a promising candidate for desalination of seawater and brackish water. [ABSTRACT FROM AUTHOR]

Optimal orientation is the key factor to optimize the gas separation performance of metal-organic framework (MOF) membranes. However, it is still greatly challenging to prepare large-area oriented MOF membranes for industrial applications. Herein, we prepared compact and (100) oriented zeolitic-imidazolate framework-8 (ZIF-8) membranes with membrane area up to 500 cm2 on the graphite substrate via support-induced strategy within 2 h. With membrane thickness of only 620 nm, the (100) oriented ZIF-8 membranes exhibit high gas separation performances due to the reduction of inter-crystalline defects and permeation resistance. At 100 °C and 1 bar, the separation factors of H 2 /CO 2 , H 2 /CH 4 and H 2 /C 3 H 8 are 18.5, 58.2 and 101.6, respectively, with H 2 permeance of about 160 x 10−9 mol m−2 s−1·Pa−1. The different positions of the 500 cm2 ZIF-8 membrane show complete consistency in orientation and separation performance, recommending this membrane suitable for future industrial applications. Further, also oriented ZIF-67 and MOF-303 membranes can be consistently prepared by this strategy, confirming its versatility for the preparation of large-area MOF membranes. [Display omitted] • Compact and (100) oriented ZIF-8 membranes are prepared on the graphite substrate via support-induced strategy. • The membrane area of the (100) oriented ZIF-8 membrane is up to 500 cm2. • The oriented ZIF-8 membrane displays high hydrogen permselectivity due to the reduction of inter-crystalline defects. • At 100 °C and 1 bar, the separation factors of H 2 /CO 2 , H 2 /CH 4 and H 2 /C 3 H 8 are 18.5, 58.2 and 101.6 for the ZIF-8 membrane. [ABSTRACT FROM AUTHOR]

• Compact and (110) oriented ZIF-8 membrane are prepared on the graphite substrate via electric-field-driven strategy. • Compact and (110) oriented ZIF-8 membrane is formed within 1 h at room temperature in the electric field. • The oriented ZIF-8 membrane displays high hydrogen selectivity due to the reduction of inter-crystalline defects. • At 100 ℃ and 1 bar, the separation factors of H 2 /CO 2 , H 2 /CH 4 and H 2 /C 3 H 8 are 49.5, 90.9 and 121.8 for the ZIF-8 membrane. Metal-organic framework (MOF) membranes have showed great potential in gas separation. To date, it is still a great challenge to precisely control the optimal orientation of MOF membranes with an enhanced gas separation performance. Herein, we prepared a compact and (110) oriented ZIF-8 membrane with a thickness of about 265 nm on graphite substrate within 1 h at room temperature via electric-field-driven strategy. Since the membrane is an intergrown one-crystal layer, grain boundary retardation of the flux is eliminated. Furthermore, due to the reduction of the transport pathways through the oriented structure, the (110) oriented ZIF-8 membrane exhibits a high gas separation performance. At 100 °C and 1 bar for the separation of equimolar binary gas mixtures H 2 /CO 2 , H 2 /CH 4 and H 2 /C 3 H 8 , separation factors of 49.5, 90.9 and 121.8 can be obtained, with H 2 permeance of about 1.7 × 10-7 mol·m−2·s−1·Pa−1. The developed strategy exhibits excellent reproducibility and scalability, and a large area ZIF-8 membrane can be consistently prepared on the graphite substrate, thus facilitating the preparation and application of the ZIF-8 membrane on a large scale. Further, the electric-field-driven strategy is also helpful for the preparation oriented ZIF-67 and ZIF-L membranes, confirming its versatility for the preparation of oriented MOF membranes. [ABSTRACT FROM AUTHOR]

Sialic acid (SA) is a crucial component of glycoproteins and glycolipids on the cellular membrane, which is essential for maintaining the function of cell membranes, such as cell recognition and communication. Simultaneously, sialic acid plays a significant role in many physiological and pathological processes. Hence, it is urgent to develop a simple and sensitive strategy for determining sialic acid. In this work, a new metal-organic framework called UiO-66-NH 2 @B(OH) 2 has been designed and synthesized for the recognition and detection of sialic acid. The boronic acid functional group in UiO-66-NH 2 @B(OH) 2 can bind to a diol moiety of the glycerol side chain of sialic acid, which will attenuate or even quench the fluorescence of UiO-66-NH 2 @B(OH) 2 , thus opening a new road to detect sialic acid. Based on the measurement results, sialic acid can be quantitatively measured in a linear range of 0.05–2.5 mmoL/L with the UiO-66-NH 2 @B(OH) 2 probe. The detection limit of sialic acid is as low as 0.025 mmol/L. Furthermore, the boronic-acid functionalized probe UiO-66-NH 2 @B(OH) 2 displays high sensitivity and high selectivity to recognize the sialic acid in mouse serum samples. Therefore, the developed UiO-66-NH 2 @B(OH) 2 can be used as a promising probe to identify and detect sialic acid in the practical application. [Display omitted] • A boronic acid functionalized metal-organic framework UiO-66-NH 2 @B(OH) 2 is prepared by one-step solvothermal method. • The UiO-66-NH 2 @B(OH) 2 is developed as fluorescence probe for determination of sialic acid. • The UiO-66-NH 2 @B(OH) 2 probe displays high sensitivity and high selectivity for detection of sialic acid. • The UiO-66-NH 2 @B(OH) 2 is promising probe to identify and detect sialic acid in the practical application. [ABSTRACT FROM AUTHOR]

The conversion of CO 2 into methanol has emerged as a promising strategy for addressing climate change and optimizing the utilization of carbon resources. Conventional synthesis methods for Cu-based catalysts, such as co-precipitation, necessitate the consumption of substantial amounts of solvent and meticulous control over preparation conditions, while also being susceptible to deactivation by water during hydrogenation. Therefore, it is crucial to develop a catalyst that can be readily synthesized and exhibits outstanding performance and durability. In this study, we present an ultrafast (only 20 min), solid-phase grinding approach to fabricate CuO-ZnO@Cu-MOR catalysts for CO 2 hydrogenation to methanol. The resulting catalysts were comprehensively characterized using XRD, XPS, H 2 -TPR, NH 3 -TPD, SEM, HRTEM, and In-situ-FTIR techniques. Notably, the CuO-ZnO@Cu-MOR catalysts with a distinctive capsule-like structure displayed a high catalytic performance for CO 2 hydrogenation. The byproducts of methane and water produced by the CO 2 hydrogenation process were able to be further converted to methanol through Cu-MOR, leading to a significant enhancement of the methanol selectivity (95.6 %) and CO 2 conversion (22.8 %). Moreover, a long-term test lasting 300 h demonstrated constant catalytic performances and superior durability. [Display omitted] • Homogeneous and capsule-like structure of CuO-ZnO@Cu-MOR catalysts were rapidly synthesized by solid grinding method. • The capsule-like structure can uniformly disperse CuO-ZnO on Cu-MOR surface. • The developed CuO-ZnO@Cu-MOR catalysts displayed high catalytic performances for CO 2 hydrogenation to methanol. • The CuO-ZnO@Cu-MOR catalysts showed stable CO 2 hydrogenation performance during 300 h operation. [ABSTRACT FROM AUTHOR]

The hydrogenation of sequestrated CO2 to methanol can reduce CO2 emission and establish a sustainable carbon circuit. However, the transformation of CO2 into methanol is challenging because of the thermodynamic equilibrium limitation and the deactivation of catalysts by water. In the present work, different reactor types have been evaluated for CO2 catalytic hydrogenation to methanol. Best results have been obtained in a bifunctional catalytic membrane reactor (CMR) based on a zeolite LTA membrane and a catalytic Cu‐ZnO‐Al2O3‐ZrO2 layer on top. Due to the in situ and rapid removal of the produced water from the catalytic layer through the hydrophilic zeolite LTA membrane, it is effective to break the thermodynamic equilibrium limitation, thus significantly increasing the CO2 conversion (36.1 %) and methanol selectivity (100 %). Further, the catalyst deactivation by the produced water can be effectively inhibited, thus maintaining a high long‐term activity of the CMR. [ABSTRACT FROM AUTHOR]

So far, the reports of ZIF-67 membranes with high permselectivity are rather scarce because ZIF-67 prefers to homogeneous nucleation and growth in the reaction solution rather than heterogeneous nucleation and growth on the substrates. Inspired by the fact that homologous metal ions is helpful to be acted as nucleation centers to promote the preparation of continuous MOF membranes, in this work, we develop a novel and effective synthesis method for in-situ growth of compact ZIF-67 membranes by using Co2+ ions chelated PIM-1 (PIM = polymer of intrinsic microporosity) as interface layer between the ZIF-67 membrane and the α-Al 2 O 3 support. After solvothermal synthesis for 48 h at 120 °C, a well-intergrown ZIF-67 membrane with a thickness of about 12 μm can be formed on the Co2+@cPIM-1 modified α-Al 2 O 3 disk. For single gas permeation at 25 °C and 1 bar, the ZIF-67 membrane shows a high H 2 permeance of 6.2 × 10−7 mol m−2 s−1·Pa−1, with H 2 /CO 2 , H 2 /CH 4 and H 2 /C 3 H 8 ideal separation factors of 15.1, 51.7 and 56.4, respectively. Further, other compact and H 2 permselective ZIF membranes, such as ZIF-7 and ZIF-8 membranes, can be consistently prepared on the Zn2+@cPIM-1 modified substrates by using the same strategy. Image 1 ● Co2+ ions chelated PIM-1 was used as interface layer to promote nucleation and growth of compact ZIF-67 membranes ● The developed ZIF-67 membrane displayed high hydrogen permselectivity ● The developed synthesis strategy is simple, versatile and effective to prepare various compact ZIF membranes [ABSTRACT FROM AUTHOR]

Because of the increase of industrial wastewater containing insoluble oil and oil discharged accidents, oil/water separation has turned out an exceedingly crucial and urgent issue in environmental protection. Therefore, it is terribly significant to develop a simple and effective technology for oil/water separation. Membrane separation has been well known as a promising method to remove oils from water due to its energy-efficiency and cost-effectiveness. In the present work, we report the synthesis of a hydrophobic zeolite FAU named F-FAU through a simple and effective post-synthetic modification. Firstly, a thin zeolite FAU layer is grown on the 3-aminopropyltriethoxysilane (APTES) modified stainless steel net (SSN) to form SSN supported FAU (SSN@FAU) coating. And then, a hydrophobic SSN@F-FAU coating is prepared through post modification of SSN@FAU coating with perfluorooctyltriethoxysilane (POTS). After POTS modification, the water contact angle (CA) of the SSN@FAU coating increases from 15° to 132° for SSN@F-FAU coating, while both morphology and structure of the SSN@FAU coating keep unchangeable. Attributing to the high hydrophobicity of the F-FAU coating, the SSN@F-FAU coating shows a wonderful oil/water separation performance, with oil/water separation efficiency of above 98.8 % and oil flux of up 50,000 L m−2 h-1. After 50 cycles successive separation of hexane/water mixture, the separation efficiency of the SSN@F-FAU coating keeps constant (over 99.1 %), showing potential application for oil/water separation in industries. Further, hydrophobic SSN@F-LTA coating can be consistently prepared through post modification of SSN@LTA coating with POTS, and also shows a high oil/water separation performance, with oil/water separation efficiency above 99.0 % and oil flux over 40,000 L m−2 h-1, confirming the universality of the preparation strategy. [ABSTRACT FROM AUTHOR]

Abstract A series of aliphatic terminal diamines with different kinetic diameter length, including 1,2-diaminoethane (A2), 1,3-diaminopropane (A3), 1,4-diaminobutane (A4), 1,5-diaminopentane (A5), 1,6-diaminlhexane (A6), 1,7-diaminoheptane (A7), and 1,8-diaminooctane (A8), were selected as built-in molecules of graphene oxide (GO) to fabricate diamine modified graphene oxide nanosheets (Ax-GO). Through vacuum filtration method, diamine modified Ax-GO membranes with tunable interlayer spacing were deposited on the polydopamine (PDA) modified α-Al 2 O 3 supports. The separation performances of the Ax-GO membranes were evaluated for seawater desalination by pervaporation. It is found that the water fluxes of the Ax-GO membranes increase with the enhancement of the interlayer spacing of the Ax-GO. Impressively, A4-GO membrane displays the best performance with water flux of 19.7 kg·m−2·h−1 and ion rejection of 99.9% at 90 °C for desalination of 3.5 wt% seawater. Further, A4-GO membrane shows high stability for seawater desalination, and the desalination performance keeps unchanged up to 168 h at 75 °C. Graphical abstract Unlabelled Image Highlights • Covalent modification strategy is developed to prepare graphene oxide framework • Aliphatic terminal were selected for cross-linking modification of graphene oxide • Diamine modified graphene oxide (Ax-GO) membranes were prepared facilely. • A4-GO membrane display high desalination performance and stability [ABSTRACT FROM AUTHOR]

Abstract A new UiO-66-NH 2 based MOF named UiO-66-NH 2 @ICA has been prepared by grafting imidazole-2-carbaldehyde (ICA) to UiO-66-NH 2 through a post-synthesis reaction via amine condensation. FESEM, XRD, 1H NMR, FT-IR and N 2 adsorption were used to characterize the morphology and structure of UiO-66-NH 2 @ICA. The grafted ICA mainly reduces the pore volume of UiO-66-NH 2 but increases the number of nitrogen atom as binding site of CO 2. The UiO-66-NH 2 @ICA showed less BET surface area but a higher CO 2 /CH 4 adsorption selectivity in comparison with UiO-66-NH 2. UiO-66-NH 2 @ICA and UiO-66-NH 2 crystals were dispersed in Matrimid®5218 to form mixed-matrix membranes (MMMs). Single gas permeation and mixed gas separation was carried out to investigate the effects of filler loading and feed gas pressure on the separation performances of the MMMs. The UiO-66-NH 2 @ICA/Matrimid® MMM with 10 wt % filler showed a high CO 2 /CH 4 selectivity with a separation factor of 64.7, which is an increase by 40% in comparison with UiO-66-NH 2 /Matrimid® MMM. Graphical abstract Image 1 Highlights • UiO-66-NH 2 @ICA was prepared by grafting imidazole-2-carbaldehyde (ICA) to UiO-66-NH 2. • Nitrogen atoms as CO 2 binding site increased after post-synthetic modification of UiO-66-NH 2. • UiO-66-NH 2 @ICA showed a higher CO 2 /CH 4 adsorption selectivity than UiO-66-NH 2. • UiO-66-NH 2 @ICA/Matrimid® MMMs displayed a high CO 2 /CH 4 separation selectivity. [ABSTRACT FROM AUTHOR]

Because of poor heterogeneous nucleation of MOF on the ceramic support surface, it is usually difficult to prepare defect-free metal-organic framework (MOF) layers as shape-selective membrane on the native ceramic supports by a direct solvothermal synthesis route. In the present work, inspired by “like dissolves like” principle, a simple and facile synthesis strategy was developed to prepare highly reproducible and permselective zeolitic imidazolate framework ZIF-8 membranes on the 1H,1H,2H,2H-perfluoroalkyltriethoxysilanes (POTS) modified α-Al 2 O 3 disks. Attributing to the enhancement of surface hydrophobicity of the α-Al 2 O 3 supports after POTS modification, hydrophobic ZIF-8 membranes are tending to grow well on the hydrophobic surface following the “like grows like” principle. Thus a well-intergrown ZIF-8 membrane with a thickness of about 20 µm has formed on the POTS-modified α-Al 2 O 3 disks. The developed ZIF-8 membranes show high hydrogen selectivity and thermal stability. At 200 °C and 1 bar, the mixture separation factors of H 2 /CO 2 , H 2 /N 2 , H 2 /CH 4 , and H 2 /C 3 H 8 are 15.8, 22.6, 40.6, and 549.3, with H 2 permeances higher than 2.1 × 10 −7 mol·m −2 ·s −1 ·Pa −1 , which is promising for hydrogen separation and purification. [ABSTRACT FROM AUTHOR]

The fabrication of mixed matrix membranes (MMMs) by intermixing suitable fillers with organic polymers is an effective strategy to surmount the well-known trade-off effect between gas permeability and selectivity, which can promote separation performance of membranes to a great extent. Two-dimensional (2D) metal-organic frameworks (MOFs) are considered as potential fillers for strengthening the separation performance of MMMs as they possess high aspect ratio and distinctive chemical characteristics. However, it remains challenging in engineering the morphology of the MOFs with desired pore structure and high aspect ratio. In this study, we firstly prepare c-axis oriented ZIF-95 sheets with lateral dimension exceeding 22 μm and thickness of around 3 μm by the solvothermal method. And then the ZIF-95 sheets are incorporated into the polyimide (PI) matrix to fabricate highly c -axis oriented ZIF-95@PI MMMs (denoted as COZIF-95@PI MMMs thereafter). Attributing to the straight permeation channel of ZIF-95 (3.6 Å) for gas permeation as well as its high compatibility with polyimide substrates, the COZIF-95@PI MMMs show a high gas separation capability. At 373 K and 100 kPa for the COZIF-95@PI MMM with 40 wt% loading, the mixture separation factors of H 2 /CH 4 and H 2 /CO 2 are 134 and 58, respectively, and the H 2 permeability exceeds 967 barrer , which is hopeful for the separation and purification of hydrogen. [Display omitted] • ZIF-95 sheets with well-shaped morphology and high aspect ratio are successfully synthesized. • The ZIF-95 sheets are used as fillers for fabrication of highly c -axis oriented mixed matrix membranes. • The straight permeation channel of ZIF-95 along c -axis orientation is dominant for gas permeation. • The developed ZIF-95 mixed matrix membranes display high hydrogen permselectivity. [ABSTRACT FROM AUTHOR]

Compact and phase-pure UiO-66-NH 2 membranes were synthesized on the 3-aminopropy-ltriethoxysilane (APTES) modified macroporous Al 2 O 3 tubes through a repeated synthesis strategy. APTES acts as a molecular linker for anchoring the metal ions onto the support surface to promote the nucleation and the crystallization of UiO-66-NH 2 membrane. Therefore, well-intergrown UiO-66-NH 2 membranes could be prepared through a repeated synthesis method on the APTES-modified macroporous Al 2 O 3 tubes. The developed UiO-66-NH 2 membranes were evaluated for seawater desalination by pervaporation. It is found that the UiO-66-NH 2 membranes show high desalination performances attributing to the narrow pore size which is exactly in between the size of water molecules and hydrated ions. With increasing the feed temperature from 318 to 363 K, the water fluxes increase from 1.5 to 12.1 kg m −2 h −1 , with ions rejections of above 99.7%. Further, the UiO-66-NH 2 membranes display high stability for a long time in seawater desalination, which is very promising for seawater desalination. [ABSTRACT FROM AUTHOR]

Transition metal phosphides are considered as promising alternatives to noble-metal based electrocatalysts for water splitting due to their bifunctional catalytic activity. The modulation of morphology and electronic structure is an efficient strategy to improve the mass transport and electronic conductivity of metal phosphides, but still faces a great challenge to achieve this conjoint regulation. Herein, a facile Zn-doped strategy was developed to synthesize cobalt phosphide (CoP) catalyst with thickness-controlled porous nanosheet structure. At the current density of 10 mA cm−2, the optimized Zn 0.1 -CoP catalyst delivers an overpotentials of 290 mV and 98 mV for OER and HER, respectively. The cell voltage for the overall water splitting is 1.57 V to reach the current density of 10 mA cm−2, outperforming the counterparts of noble metal-based Pt/C and IrO 2 catalysts. The density functional theory (DFT) calculations reveal that Zn doping can effectively improve the conductivity and regulate the electronic structure of CoP, thus resulting in fast charge transfer transport and reduced energy barrier of the rate-determining step. This work provides a favorable strategy for the rational design of bifunctional catalysts with high-performance for overall water splitting. [Display omitted] • The Zn-doped CoP electrocatalysts with controllable morphology and electronic structure have been facilely synthesized • Zn-doped CoP porous nanosheets and its in -situ transformed Zn-CoOOH exhibit enhanced catalytic properties • The electronic structure and intrinsic catalytic activity of CoP can be finely regulated by Zn doping • The designed Zn 0.1 -CoP catalyst shows superior water-splitting performance to the commercial Pt/C-IrO 2 catalysts [ABSTRACT FROM AUTHOR]

In the present work, we report a new road to enhance the gas separation performances of the zeolite Na-LTA membrane by tuning the pore size of zeolite LTA through silver cation exchange. Through the functionalization of the alumina support by using 3-aminopropyltriethoxysilane (APTES), a thin, phase-pure and well intergrown zeolite Na-LTA membrane with a thickness of about 5.0 µm can be facilely prepared on the APTES-modified macroporous α-Al 2 O 3 tube. After a following silver exchange treatment of the as-synthesized zeolite Na-LTA membranes, the sodium ions in zeolite Na-LTA framework are replaced by silver ions, thus forming zeolite Ag-LTA membranes with a narrower pore diameter. The zeolite Ag-LTA membranes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). It is found that both the morphology and structure of the zeolite Na-LTA membrane keep unchanged after silver-exchange, and no cracks, pinholes or other defects are observed in the membrane layer. The zeolite Ag-LTA membrane shows high hydrogen selectivity due to the reduction of pore size of the zeolite Ag-LTA. For the separation of the binary mixture at 50 °C and 2.0 bar, the separation factor of H 2 /C 3 H 8 is α≈120.8, which by far exceeds α≈19.4 of the starting Na-LTA membrane, and are also much higher than the separation factors previously reported for the H 2 /C 3 H 8 mixture on zeolite membranes. [ABSTRACT FROM AUTHOR]

It is well known that graphene oxide (GO) is highly stable in air or water. However, the stability of asymmetric graphene oxide (GO) membrane depends on the chemistry of the support and also the thickness of the targeted coated GO layer. It is found that the GO membranes prepared on porous Al 2 O 3 supports are unstable, and easy to crinkle and finally peel off from the support surface in a short time due to poor interaction with the support surface. In the present work, we have successfully prepared highly stable, permselective and reproducible GO membranes for seawater desalination by using polydopamine (PDA) as a novel covalent linker. Attributing to the high adhesive ability of PDA, GO nanosheets are attracted and bound onto the support surface, thus remarkably enhancing the stability of the GO membranes. It is found that the developed GO membranes are very promising for seawater desalination. For desalination of 3.5 wt% seawater at 90 °C, high water fluxes of 48.4 kg m −2 h −1 and high ion rejections of over 99.7% can be obtained for the GO membrane which are much higher than those obtained from conventional porous inorganic membranes. [ABSTRACT FROM AUTHOR]

Through bio-inspired polydopamine modification of the ceramic support surface, dense and reproducible zeolitic imidazolate framework (ZIF) membranes have been developed for the first time for seawater desalination by pervaporation. Demonstrated by both experimental and simulation studies, the developed ZIF membranes show high desalination performances attributing to the small pore size of the ZIF membranes, which is exactly in between the size of water molecules and hydrated ions. The ZIF membranes show a high stability in seawater. At 25, 50, 75 and 100 °C, the water fluxes through the ZIF-8 membrane are 5.8, 8.1, 10.8, and 13.5 kg/(m 2 ·h), respectively, with a high ion rejection of over 99.8%, which is promising for seawater desalination by ionic sieving. [ABSTRACT FROM AUTHOR]

Oil-in-water (O/W) emulsion is considered to be difficult to treat. In this work, a low-cost multi-layer-structured mullite-titania composite ceramic hollow fiber microfiltration membrane was fabricated and utilized to efficiently remove fine oil droplets from (O/W) emulsion. In order to reduce membrane cost, coal fly ash was effectively recycled for the first time to fabricate mullite hollow fiber with finger-like and sponge-like structures, on which a much more hydrophilic TiO 2 layer was further deposited. The morphology, crystalline phase, mechanical and surface properties were characterized in details. The filtration capability of the final composite membrane was assessed by the separation of a 200 mg·L −1 synthetic (O/W) emulsion. Even with this microfiltration membrane, a TOC removal efficiency of 97% was achieved. Dilute NaOH solution backwashing was used to effectively accomplish membrane regeneration (∼96% flux recovery efficiency). This study is expected to guide an effective way to recycle waste coal fly ash not only to solve its environmental problems but also to produce a high-valued mullite hollow fiber membrane for highly efficient separation application of O/W emulsion with potential simultaneous functions of pure water production and oil resource recovery. [ABSTRACT FROM AUTHOR]

CO 2 hydrogenation to dimethyl ether (DME) has drawn increasing interest in science and industry. However, the conversion of CO 2 to DME is challenging due to the limitation of thermodynamic equilibrium and the water-induced degradation of the catalysts in a catalytic fixed bed reactor (CFBR). In this study, a novel reaction-separation coupling Cu–ZnO–Pt@HZSM-5 catalytic membrane reactor (CMR) was fabricated for CO 2 hydrogenation to DME. Owing to continuous separation of the by-product steam by using an HZSM-5 membrane, the limitation of thermodynamic equilibrium can be broken effectively, thus leading to a substantially enhanced CO 2 conversion (from 24.9% in the CFBR to 41.1% in the CMR) and DME selectivity (from 53.7% in the CFBR to 100% in the CMR). Further, water-induced degradation of the catalyst can be restrained because of water removal, thus keeping a high catalytic activity for a long time. [Display omitted] • Cu–ZnO–Pt@HZSM-5 catalytic membrane reactor is proposed for dimethyl ether formation from CO 2 hydrogenation. • The thermodynamic limitation can be overcome by the coupling of reaction and separation in one reactor. • High CO 2 conversion of 41.1% and dimethyl ether selectivity of 100% are obtained under 3.25 MPa and 280 °C. [ABSTRACT FROM AUTHOR]

A seeding-free synthesis strategy was developed for the preparation of dense and phase-pure zeolite FAU membranes through mussel-inspired polydopamine (PDA) modification of porous Al 2 O 3 tubes. Zeolite FAU nutrients can be attracted and bound to the support surface via the formation of strong non-covalent and covalent chemical bonds, thus promoting the nucleation and growth of uniform, well-intergrown and phase-pure zeolite FAU membranes. The SEM and XRD characterizations demonstrate that a relative thin but dense and pure-phase zeolite FAU membrane with a thickness of about 2.3 µm can be obtained on the PDA-modified Al 2 O 3 tube after crystallization at 75 °C for 24 h, and no visible cracks, pinholes or other defects are observed on the membrane layer. The zeolite FAU membrane prepared at 75 °C for 24 h was evaluated in single gas permeation and mixed gas separation. For binary mixtures at 50 °C and 1 bar, the mixture separation factors of H 2 /CH 4 and H 2 /C 3 H 8 are 9.9 and 127.7, respectively, which are much higher than the corresponding Knudsen coefficients. And relative high H 2 permeance of about 1.9×10 −7 mol m −2 s −1 Pa −1 can be obtained through the FAU membrane due to the thin layer and the relative wide pore size of 0.74 nm, demonstrating a viable direction for promising application of FAU membranes in hydrogen purification and separation. [ABSTRACT FROM AUTHOR]

Highly hydrogen-permselective zeolitic imidazolate framework ZIF-8 membranes are prepared on coarse and macroporous Al 2 O 3 tubes through a repeated synthesis strategy for the separation of H 2 /CO 2, H 2 /CH 4 , and H 2 /C 3 H 8 mixtures. Since the amino-groups of 3-aminopropyltriethoxysilane (APTES) can coordinate to the free Zn 2+ centers and thus bind the growing nano-crystals directly, the nucleation and growth of well intergrown ZIF-8 membranes could be promoted through a repeated synthesis of the ZIF-8 layer on APTES-modified macroporous Al 2 O 3 tubes. The SEM and XRD characterizations indicate that a dense and phase-pure ZIF-8 membrane with a thickness of about 25.0 μm can be formed on the alumina tubes by microwave synthesis at 105 °C for 3 h, and no cracks, pinholes or other defects were observed in the membrane layer. The ZIF-8 membranes were evaluated in single gas permeation and mixed gas separation. Attributed to the preferential adsorption affinity and capacity as well as a highly porous structure with nano-sized channels, the ZIF-8 membrane displays a high hydrogen permselectivity. For the separation of equimolar H 2 /CO 2 , H 2 /CH 4 , H 2 /C 3 H 8 mixtures at 100 °C and 2 bar, the mixture separation factors of H 2 /CO 2 , H 2 /CH 4 , and H 2 /C 3 H 8 are 5.6, 44.0, 328.6, with a H 2 permeance of about 1.1 × 10 −7 mol m −2 s −1 Pa −1 , which is promising for potential applications in hydrogen purification and separation. [ABSTRACT FROM AUTHOR]

Mg-MOF-74 has attracted intense attention due to its high CO 2 uptake ability. In this work, a new strategy by using magnesium oxide as seeds was developed to synthesize a dense, defect-free Mg-MOF-74 membrane with hydrogen-selectivity. The mixed gas separation factor of H 2 /CO 2 mixture could be improved by the post-modification of the Mg-MOF-74 membrane with ethylenediamine, since the modification with amine groups enhanced the strong adsorption of CO 2 molecules, which reduces the permeance of CO 2 . The separation factors for both as-synthesized and amino-functionalized Mg-MOF-74 membranes reduce gradually with increasing temperature. After amination of the open Mg sites, the separation performance of the Mg-MOF-74 membrane was remarkably enhanced, and the H 2 /CO 2 selectivity increased from 10.5 to 28 at room temperature. [ABSTRACT FROM AUTHOR]

• One-pot method was developed for the facile synthesis of ZIF-67/PPy heteroaerogels. • The ZIF-67/PPy heteroaerogels exhibit excellent conductivity and high specific capacitance of 1241F g−1 at 1 A g−1. • The ZIF-67/PPy heteroaerogels show excellent stability with specific capacitance retention of 91% after 10,000 cycles. The poor electrical conductivity of the metal organic frameworks (MOFs) limits their application in the supercapacitors. Here we developed a versatile strategy to effectively incorporate the conductive polymer polypyrrole (PPy) into ZIF-67 by in-situ polymerization and crystallization. Attributed to the stereoscopic surrounding of ZIF-67 with the conductive PPy, which is helpful for fast transfer of the electron/ion, the ZIF-67/PPy heteroaerogel exhibits a high specific capacity (1241F g−1 at 1A g−1) and high stability with 91% retention rate after 10,000 cycles measurement at 10 A g−1. The appealing electrochemical performance of the ZIF-67/PPy heteroaerogel recommends its promising application in supercapacitors. [ABSTRACT FROM AUTHOR]

Water permeation through a hydrophilic zeolite membrane can be used to promote reactions under equilibrium controlled conditions through the in situ removal of the by-product water. In the methylamine synthesis, mono- (MMA), di- (DMA) and trimethylamine (TMA) are formed by the successive methylation of ammonia with methanol (MeOH) over a mildly acidic catalyst. The methylamine yield can be increased through selective water extraction from the reactor through a membrane. Since both reactants and water have similar molecular kinetic diameters below 3.7 Å, because of the limited steam selectivity of the commonly used hydrophilic Na-LTA membrane (zeolite 4A), not only water has been removed. Therefore, in this work a K-LTA membrane, which was obtained by ion exchange with a reduced pore window diameter of 3 Å and thus with a higher water selectivity, was used in the membrane-supported methylamine synthesis. When replacing the Na-LTA with the K-LTA membrane, the H 2 O/MeOH mixed gas separation factor increases up to 1100 and the H 2 O/NH 3 separation could also be improved. This in turn leads to an overall boost of the higher methylated amines DMA and TMA in methylamine synthesis. When using the narrow-pore aluminosilicate catalyst H-SSZ-13 with CHA structure, the application of the K-LTA membrane increases the share of the industrially desired product DMA from 51% without membrane to 74% with slightly increased conversion. When using the large-pore catalyst H-MOR, the thermodynamically most stable product TMA can be formed and the selectivity was increased from 35% without membrane to 41% with the K-LTA membrane. [Display omitted] • Linde Type A membranes were evaluated for application in methylamine synthesis. • In situ water removal enhanced methylation rate and conversion rates. • K+ exchanged variant showed promising water/methanol selectivities. [ABSTRACT FROM AUTHOR]

Abstract: By PFG NMR diffusion measurements with short-chain length alkanes, the deposition of nano-sized LTA zeolite seed crystals on LTA single crystals and their secondary growth to surface layers is shown to reduce rather than to enhance transport resistances at the crystal surface. This, at first glance contra-intuitive, finding may be rationalised if the transport resistance on the external surface of the nanoporous crystals of the as-synthesized material results from an essentially impenetrable layer with highly dispersed structural defects rather than from a quasi-continuous layer with extremely low guest diffusivity and/or solubility: if accompanied with an – even very small – enhancement of the defect density, irrespective of the increasing layer thickness a subsequent surface treatment will enhance the surface permeability. [Copyright &y& Elsevier]

Hydrogen-bonded Organic Frameworks (HOFs), consisting of H-bonds and strong π-π interaction, are novel materials with ordered and flexible porous frameworks. With permanent porosity, HOFs are considered as a promising material for large-scale preparation of gas separation membranes owing to their superior stability. Herein, we report a novel HOF-based Mixed-Matrix Membrane (MMM) termed HOF-30@PI by blending HOF-30 crystals with PolyImide (PI) for hydrogen separation. The added amount of HOF-30 has a crucial effect on gas separation performance. A HOF-30@PI MMM with 10 wt% HOF-30 exhibits a high hydrogen permeability of 428.1 barrer and H 2 /CH 4 separation factor of 61.7. Owing to good compatibility and the proper pore size of HOF-30 with 4 Å, the HOF-30@PI MMM shows excellent stability and has no obvious separation performance degradation after a 240 h testing. Interestingly, HOF-30@PI MMM has a certain response on pressure because of its flexibility due to hydrogen bonds. Therefore, the usage of HOFs as porous fillers in MMM develops a novel way toward the tailored synthesis of advanced composite membrane materials for gas separation. [Display omitted] • A HOF is used as a filler to fabricated MMMs for gas separation for the first time. • HOF-30 based HOF-30@PI MMM is prepared by scraping method. • The developed HOF-30@PI MMM shows a high H 2 permeability and selectivity. [ABSTRACT FROM AUTHOR]

Due to their rationally controlled pore size and easy functionalization, metal-organic frameworks (MOFs) are a promising candidate for membrane separation. As one of the most stable MOFs, UiO-66 has attracted intense attention for the preparation of molecular sieving membranes. A new post-synthesis modification (PSM) strategy was developed to enhance the separation selectivity of supported UiO-66-NH 2 membranes on porous ceramic tubes called UiO-66-NH 2 @SA by using salicylaldehyde (SA) modification. The mixed gas separation factors of H 2 /CO 2 and H 2 /CH 4 can be improved due to constrictions of the pore size through reaction of –NH 2 with SA giving iminophenol moieties. Notably, SA-modified UiO-66-NH 2 membranes are rather stable, at a high operation temperature of 200 °C and 1 bar, mixture separation factors of 11.3 for H 2 /CO 2 and 22 for H 2 /CH 4 can be obtained. Further, no obvious performance degradation has been observed after 3 months storing in air. This high stability of UiO-66-NH 2 @SA membrane could provide possibility for the industrial applications of hydrogen separation and purification. Image 1 • Dense UiO-66-NH 2 membranes are prepared on APTES-modified macroporous α-Al 2 O 3 tubes. • A new post-synthesis modification strategy was developed to enhance the separation selectivity of UiO-66-NH 2 membranes. • The developed UiO-66-NH 2 @SA membranes show high separation performances for hydrogen purification. [ABSTRACT FROM AUTHOR]

• Green template-free synthesis of Co 3 O 4 without using capping agent via one-step hydrothermal method. • Different morphology of Co 3 O 4 (cube, truncated octahedron and octahedron) have been synthesized. • The Co 3 O 4 cube performs the best catalytic activity towards CO oxidation. A facile and green template-free hydrothermal method was conducted to controllably synthesize spinel type cobalt oxides (Co 3 O 4) with cube, truncated octahedron and octahedron morphologies. The catalytic performance over various shapes of catalysts was investigated towards CO oxidation. Among of them, the Co 3 O 4 cube performs the best catalytic activity, which can even be comparable to those of certain noble metal catalysts. The phenomenon might be ascribed to the synergistic effects of exposed Co3+ active sites and surface oxygen distribution on the surface of the catalyst. The results may provide significant insights for the fabrication of metal oxide catalysts for CO oxidation. [ABSTRACT FROM AUTHOR]

A well-shaped Ce (IV)-based metal organic framework (Ce-BDC) is prepared under solvothermal method. The influence of synthesis time, temperature and the amount of acetic acid (HAc) as a modulator is studied to develop a new strategy for the synthesis of well-shaped Ce-based MOF. The relationship between the synthesis parameters and morphology as well as crystallinity of Ce-BDC is investigated by XRD and SEM. Furthermore, the obtained well-shaped Ce-BDC shows a CO 2 uptake capacity of 2.28 mmol g−1 at 0 °C and 1.0 bar. Meanwhile, the breakthrough curve behaviors of Ce-BDC are investigated for a CO 2 /CH 4 and CO 2 /N 2 mixture gas. It is found that the Ce-based MOF adsorbs CO 2 under ambient temperature and pressure, but completely excludes CH 4 and N 2 , suggesting that it is a promising adsorbent for efficient separation of CO 2 from natural gas. Image 1 • Well-octahedral Ce-BDC MOF is prepared by solvothermal method. • The influence of different synthesis parameters are investigated for the synthesis of well-shaped MOF. • The prepared Ce-BDC exhibits high CO 2 /CH 4 and CO 2 /N 2 adsorption selectivity. [ABSTRACT FROM AUTHOR]

Thin, phase-pure and well inter-grown zeolite FAU membranes are synthesized upon modifying the tubular supports using 3-aminopropyltriethoxysilane (APTES). The as-synthesized zeolite FAU membranes are evaluated in the dewatering of dimethyl carbonate (DMC) by pervaporation. Due to the large pore size (0.74 nm) and high hydrophilicity of zeolite FAU, the prepared zeolite FAU membranes exhibit high water flux and separation performance for the separation of H 2 O and DMC. With increasing the temperature or water content in the feed, the zeolite FAU membranes show higher flux while maintaining high separation factors. Further, for dewatering of 10 wt% H 2 O/90 wt% DMC mixtures at 353 K in a lab device, the DMC concentration in the feed side reaches 99% after continuously dewatering over 9 h. Besides, the zeolite FAU membranes are also successfully prepared on commercial tubular size of 80 cm and 100 cm long α-Al 2 O 3 tubes. The obtained membranes show high separation performance for the dewatering of DMC solution as well. The high-performance zeolite FAU membrane offers great potential for dewatering of DMC solutions in industry. Image 1 • Large tubular zeolite FAU membrane is prepared upon modifying the support. • The prepared zeolite FAU membrane shows high DMC/H 2 O separation performance. • Large tubular zeolite FAU membrane exhibits good separation performance. [ABSTRACT FROM AUTHOR]

With ordered and periodic network structures, adjustable pore sizes and high chemical stability, covalent organic frameworks (COFs) have drawn much attention for the fabrication of superior separation membranes. However, it is challenging to prepare COF membranes with a molecular sieving property for gas separation due to their relatively large pore size. In this work, we develop the MOF-in-COF concept for vacuum-assisted synthesis of metal-organic framework (MOF) ZIF-8 inside the pores of TB-COF formed from trihydroxy-benzene-tricarbaldehyde (T) and diamino-biphenyl-disulfonic acid (B), thus constructing a novel ZIF-8@TB-COF membrane. Attributing to the formation of a well-defined one-dimensional (1D) nanoscale transport channel, the ZIF-8@TB-COF membrane displays a high hydrogen permselectivity. At 100 °C and 200 kPa, the mixture separation factors of H2/CO2, H2/CH4 and H2/C3H8 are 21.9, 63.1 and 134.4, respectively, which are much higher than those of the pristine TB-COF membrane due to the precise size sieving channels brought about by the incorporated MOF. The synthesis of ZIF-67@TB-COF membrane demonstrates the versatility of the synthesis strategy., (© 2024 Wiley‐VCH GmbH.)

Nanosheet-based membranes have shown enormous potential for energy-efficient molecular transport and separation applications, but designing these membranes for specific separations remains a great challenge due to the lack of good understanding of fluid transport mechanisms in complex nanochannels. We synthesized reduced MXene/graphene hetero-channel membranes with sub-1-nm pores for experimental measurements and theoretical modeling of their structures and fluid transport rates. Our experiments showed that upon complete rejection of salt and organic dyes, these membranes with subnanometer channels exhibit remarkably high solvent fluxes, and their solvent transport behavior is very different from their homo-structured counterparts. We proposed a subcontinuum flow model that enables accurate prediction of solvent flux in sub-1-nm slit-pore membranes by building a direct relationship between the solvent molecule-channel wall interaction and flux from the confined physical properties of a liquid and the structural parameters of the membranes. This work provides a basis for the rational design of nanosheet-based membranes for advanced separation and emerging nanofluidics.

The development of highly active carbon-based bifunctional electrocatalysts for both the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is highly desired, but still full of challenges in rechargeable Zn-air batteries. Metal organic frameworks (MOFs) and covalent organic frameworks (COFs) have gained great attention for various applications due to their attractive features of structural tunability, high surface area and high porosity. Herein, a core-shell structured carbon-based hybrid electrocatalyst (H-NSC@Co/NSC), which contains high density active sites of MOF-derived shell (Co/NSC) and COF-derived hollow core (H-NSC), is successfully fabricated by direct pyrolysis of covalently-connected COF@ZIF-67 hybrid. The core-shell H-NSC@Co/NSC hybrid manifests excellent catalytic properties toward both OER and ORR with a small potential gap (∆E = 0.75 V). The H-NSC@Co/NSC assembled Zn-air battery exhibits a high power-density of 204.3 mW cm -2 and stable rechargeability, outperforming that of Pt/C+RuO 2 assembled Zn-air battery. Density functional theory calculations reveal that the electronic structure of the carbon frameworks on the Co/NSC shell can be effectively modulated by the embedded Co nanoparticles (NPs), facilitating the adsorption of oxygen intermediates and leading to enhanced catalytic activity. This work will provide a strategy to design highly-efficient electrocatalysts for application in energy conversion and storage., (© 2022 Wiley-VCH GmbH.)