ABSTRACT Realizing metal‐organic framework (MOF) membranes for industrial gas separations hinges on scalable routes to dense, low‐defect layers. We report a mixed‐linker, seed‐layer‐free strategy for the one‐step growth of aluminum MOF‐303 membranes directly on porous α ‐alumina supports. Partial substitution of 3,5‐pyrazoledicarboxylic acid (H 3 PDC) with 2,5‐furandicarboxylic acid (FDCA) accelerates interfacial nucleation and promotes continuous membrane formation, obviating the conventional seeding step required for MOF‐303. Structural and spectroscopic analyses confirm uniform FDCA incorporation without perturbing the intrinsic framework chemistry. The resulting mixed‐linker membranes, exemplified by MOF‐303(P7F3) and MOF‐303(P6F4), deliver outstanding CO 2 separations: for MOF‐303(P6F4), CO 2 /N 2 separation factors reach 170 and 236 at 20% and 50% CO 2 feeds, respectively; CO 2 /CH 4 separation factors reach 431 and 393 under the same conditions, surpassing the 2019 polymeric‐membrane upper bound. Molecular simulations also indicate that FDCA incorporation leaves intrinsic adsorption and diffusivity largely unchanged, attributing the observed performance gains to improved membrane morphology and grain‐boundary suppression arising from the mixed‐linker‐directed growth. This simple, versatile route enables dense, high‐selectivity MOF‐303 membranes without seeding and is readily extendable to MOF systems where conventional in situ synthesis fails to yield defect‐minimized membranes.

Comprehensive Summary The separation of xenon and krypton gas mixtures presents a significant yet challenging task due to the close molecular sizes and similar physical properties of these gases. In this study, we present a novel microporous hydrogen‐bonded organic framework, designated as HOF‐SCU‐1, which is constructed from a carboxylic acid‐based organic linker, 3,3′,5,5′‐tetrakis(3,5‐dicarboxyphenyl)‐2,2′,4,4′,6,6′‐hexamethylbiphenyl (H 8 TDHB). HOF‐SCU‐1 demonstrates exceptional separation performance for xenon and krypton mixtures, as evidenced by dynamic breakthrough curves. Grand canonical Monte Carlo (GCMC) simulation results indicate that the effects of pore confinement and the abundance of accessible binding sites work synergistically to facilitate this challenging gas separation.

Carbon nanotubes (CNTs) have emerged as one of the most exciting families of carbon nanomaterials. Their hollow tubular architecture, with a nanometric inner cavity, not only defines their distinct physical and chemical behavior but also enables the encapsulation of a wide range of materials, including inorganic and organic compounds. This encapsulation capability allows CNTs to function as nanocontainers, protective hosts, and confined reaction vessels, leading to novel hybrid materials with tailored optical, electronic, catalytic, and mechanical properties. In this review, we provide a comprehensive overview of the methodologies employed for filling CNTs, including in situ and ex situ approaches. We critically examined the diverse range of materials encapsulated within CNTs, highlighting how confinement at the nanoscale influences their chemical reactivity, phase stability, and emergent quantum phenomena. Special attention is given to the wide range of applications of filled CNTs in addressing societal challenges. These include biomedicine, catalysis, energy storage, gas separation, filtration membranes, sensing technologies, and nanoelectronics. Beyond revisiting the current state-of-the-art, this review offers a critical discussion of future directions and challenges in this field.

The synthesis of high-nuclearity titanium metal-organic polyhedra (Ti-MOPs) has remained a formidable challenge due to the high oxophilicity and hydrolysis susceptibility of Ti4+ ions. Herein, we report a Ti24 MOP with a truncated octahedron (tro) topology, which represents the highest nuclearity Ti-MOP reported to date. Beyond structural characterization, we introduce a pathway intervention strategy using Ni2+ as a kinetic modulator to trap and structurally characterize two key intermediates-a Ti12 macrocycle and a Ti12 (6-4-6) module. These intermediates outline a hierarchical assembly pathway from simple precursors to Ti24 MOP. Furthermore, we demonstrate that this process is governed by a coordination lability gradient between Ti4+ and Ni2+, providing an effective strategy for directing supramolecular complexity. This Ti-MOP exhibits permanent microporosity, gas separation, and post-assembly modification capability. This work transforms a synthetic challenge into a strategic advantage, offering a blueprint for the rational assembly of complex metal-organic architectures.

ABSTRACT Mixed matrix membranes were produced by incorporation of SSZ‐13 zeolites into polydimethylsiloxane (PDMS) to assess the effect of filler properties and concentration on the CO 2 /N 2 separation efficiency compared to pure PDMS membranes. The membranes were produced with SSZ‐13 zeolites obtained by different hydrothermal synthesis times (1 or 4 days) and concentrations (0%–15%). All membranes were characterized and subjected to pure CO 2 and N 2 permeation tests. The highest performance was achieved through incorporation of 5% SSZ‐13 zeolites synthesized by 4‐day hydrothermal treatment, with 10.89 CO 2 /N 2 selectivity and CO 2 permeability of 2402.0 Barrer, 25.7% higher than pure PDMS. The increased performance was associated with higher diffusion rates of CO 2 when the zeolite was incorporated into the PDMS matrix. Higher percentages of SSZ‐13 led to lower separation capacity, decreased CO 2 permeability and CO 2 /N 2 selectivity. Using SSZ‐13 synthesized within 1 day resulted in membranes with reduced mechanical stability that were prone to tearing, reinforcing that proper selection of filler structural and surface properties is essential for manufacture of stable and reproducible mixed matrix membranes. Considering the trade‐off between permeability and selectivity typically observed in polymer membranes, this study highlights the potential of mixed matrix membranes to achieve incremental improvements on membrane‐based gas separation.

Selective separation of enriched dry gas for energy-efficient ethylene production: Experiments and simulations

Tailored ultramicroporous structure in CMS membranes through crosslinking and rearrangement of polyimide precursor for efficient gas separation

Fabrication of Defect-free Benzimidazole Polyimide Hollow Fiber Membranes for High Performance Gas Separation

Enhanced gas separation performance of carbon molecular sieve membranes by increasing the crosslinking density of polyimide precursors

Silica-based gas separation membranes: Structure–performance relationships across the Si–O continuum from polysilsesquioxanes to amorphous SiO2

Enhancement of the gas separation performance of mixed matrix membranes (MMMs) with functionalized triptycene hypercrosslinked polymers of intrinsic microporosity (HCP-PIMs)

An AI Framework for Optimization of Operating Conditions, Geometry, and Material Screening in Membrane Gas Separation

Fine-tuning gas separation performance of PIMs by engineering the novel tetrafluorinated monomers with aryl Schiff base units

Programmable hourglass nanochannels in thermally rearranged copolyimides for advanced gas separation

Clathrates have gained considerable attention due to their potential impact on various industries, including oil and gas production, and more recently in the fields ranging from energy storage and transportation to environmental protection and gas separation processes, opening up new technological possibilities. Overall, the attention is focused on their spontaneous and uncontrolled formation/nucleation in offshore oil and gas pipelines, which can lead to numerous and serious operational problems. Accordingly, significant research efforts have focused on understanding the mechanisms of clathrate formation and inhibition or dissociation. Different approaches are being explored; some are ambitious and innovative, whereas others seek further validation. Among these, particular interest has emerged in the coupling of Terahertz (THz) radiation with the collective low-energy and/or vibrational modes of water, and/or other molecules, as well as their clusters. In this review, we summarize recent advances and findings in this promising research field, highlighting the potential applications of THz radiation and spectroscopy, future applications in the field of clathrates, and the technological progress toward the implementation of THz-based solutions in transportation and industrial processes.

ConspectusNear-infrared (NIR) light, especially NIR-II light (1000-2000 nm), has shown extensive applications in military and civilian fields such as night vision, biomedicine, optical communication, and noninvasive detection due to its superior penetration capabilities, invisibility to human eyes, less background interference, and low optical loss in optical fibers. The development of photonic materials that can absorb or emit NIR light thus has attracted great interest. Recently, metal-organic frameworks (MOFs), which were assembled by metal nodes and organic ligands, have emerged as particularly exciting crystalline porous materials due to their prospective applications in various fields, such as gas storage and separation, chemical sensing, catalysis, proton conduction, and drug delivery. The abundant and tailorable structures, as well as permanent porosity of MOFs, render them highly promising for NIR photonic applications. MOFs allow the rational and tunable design of NIR photonic materials by the judicious incorporation of NIR-responsive inorganic and organic units with the desired functionalities. In addition, the permanent porosity of MOFs greatly extends their opportunities toward NIR photonic materials. As ordered porous materials, MOFs are able to encapsulate diverse NIR-responsive photonic species, such as lanthanide ions, organic dyes, metal complexes, perovskite quantum dots, lanthanide-doped nanoparticles, etc., into the pores or structural-defect spaces for novel NIR photonic properties. More importantly, the well-organized and tunable pores can provide identical secondary environments around photonic species and control the intermolecular interactions as well as energy/charge transfer process between guests and MOFs, thus bringing much flexibility to pursue excellent or novel NIR photonic properties.In this Account, we summarize our recent efforts in the design and construction of NIR photonic MOFs, including mixed-lanthanide MOFs, multivariate-ligand MOFs, dye-encapsulated MOFs, and nanoparticle/MOF composites, as well as their unique NIR photonic performances and various applications. We first review the design strategies and advantages of NIR photonic MOFs, and then we focus on describing the key NIR photonic functionalities in MOFs, including NIR photoluminescence, NIR-II excited multiphoton luminescence, NIR-II pumped multiphoton lasing, NIR-II harmonic frequency, and NIR-II responsive multiple nonlinear optical (NLO) behaviors. Furthermore, we discuss the applications of NIR photonic MOFs in luminescent temperature sensing, three-dimensional patterning, photonic data storage, micronano lasing, and biological imaging. Finally, we outline our perspectives on the current challenges as well as the future development of NIR photonic materials. This Account gives a comprehensive understanding of NIR photonic MOFs and thereby will be helpful to promote MOF materials to step up from fundamental synthesis to promising applications in luminescent sensing, lasing devices, data storage, photonic integrated circuits, and biomedicine.

Understanding molecular adsorption in microporous materials is key to advancing gas separation, storage, and catalysis. Here, we study CO2 and CH4 adsorption in crystalline metal-organic frameworks (IRMOF-1, 8, 10, and 14), emphasizing the emergence of metastable states. Molecular simulations reveal that adsorption is governed by a fine balance between fluid-fluid and fluid-framework interactions, leading to transitions between low- and high-density pore-filling states. These metastable features are highly sensitive to pore geometry and thermodynamic conditions, especially near the adsorbate's triple point. In contrast, water adsorption displays more complex behavior: strong hydrogen bonding induces stable clusters, multiple free energy minima, and exceptionally slow equilibration. These features often escape conventional simulations. Our results underscore the importance of metastability in accurately modeling and designing advanced nanoporous materials for practical applications.

Abstract Efficient removal of trace acetylene (C 2 H 2 ) from ethylene (C 2 H 4 ) is crucial for polymer production, yet remains challenging for physisorption separation owing to their molecular similarity. Herein, we synthesized a series of LTL zeolites with varied Si/Al ratios via an acid co‐hydrolysis route. The optimal adsorbent LTL(2.3) with a low Si/Al ratio of 2.3 exhibited both high C 2 H 2 uptake (2.79 mmol g −1 ) and C 2 H 2 /C 2 H 4 (1/99, v / v ) selectivity of 26.84 at 1 bar and 298 K, as well as superior dynamic separation efficiency. Structural refinement based on high‐resolution powder X‐ray diffraction (PXRD) patterns illustrates that reducing Si/Al ratio provides more K + cation that serves as the strong C 2 H 2 binding sites, thereby promoting the C 2 H 2 /C 2 H 4 separation. Moreover, the optimal LTL zeolite also demonstrates favorable separation efficiency towards other gas mixtures (e.g., CO 2 /N 2 , CO 2 /CH 4 , C 2 H 4 /C 2 H 6 , and C 3 H 6 /C 3 H 8 ), showing the promising potential as a versatile adsorbent for gas separation and purification.

The efficient separation of acetylene (C2H2) and carbon dioxide (CO2) is of major practical importance but remains difficult because of their analogous physical properties. The dual-ligand strategy provides an effective approach to tailor pore structure and chemical microenvironments for enhanced functionality. Nevertheless, the structural controllability of metal-organic frameworks (MOFs) assembled from tetracarboxylic acids and azole ligands remains challenging. Herein, we report a unique pillar-layered MOF, Zn-TCPB-dmtrz, constructed based on a dual-ligand strategy, demonstrating the efficient separation of C2H2/CO2. The coordination of different ligands generates 1D [Zn4N6]n chains, which function as pillars to interconnect 2D layers into a rare pillar-layered structure. The combination of abundant N/O sites and hydrophobic pore environment achieves high C2H2 adsorption capacity and excellent C2H2/CO2 separation ability. Furthermore, its relatively low C2H2 Qst, competitive thermal stability, and recyclability underscore its practicality for C2H2/CO2 separation. This study enriches the structural diversity of pillar-layered MOFs and demonstrates the controllable dual-ligand strategy based on tetracarboxylic acid and dmtrz ligands for advanced gas separation.

Identifying appropriate materials that can simultaneously ensure low production costs, scalability, and retention of intrinsic adsorption capabilities throughout the structuring process remains a significant challenge, thereby limiting the industrial implementation of adsorptive gas separation techniques. We report the first example of the structured fiber sorbents incorporating CuI-exchanged Y zeolites (CuI@Y), which can form CuI-alkyne π-complexes for the selective adsorption of acetylene from C2H2/CO2 mixtures. CuI@Y/PVDF fiber sorbents exhibited remarkable adsorption performance, including high C2H2 uptake at low partial pressure (0.775 mmol·g-1 at 10 mbar C2H2) and high IAST selectivity (11.7), even after the structuring process. The separation performance was also confirmed by the dynamic breakthrough experiments at 25 °C, demonstrating a separation factor of approximately 3.12 for a ternary C2H2/CO2/He (10/5/85, v/v/v) mixture along with excellent cyclic stability over multiple separation cycles. Notably, CuI@Y/PVDF fiber sorbents can be readily fabricated and scaled up using commercially available raw materials, with an estimated production cost of $26 per kilogram. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analyses further supported the presence of CuI-alkyne interactions, revealing distinct binding affinities for C2H2 and CO2.