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A new TIFSIX anion pillared metal organic framework ZNU-7 (ZNU = Zhejiang Normal University) with abundant electronegative sites was prepared for efficient C2H2/CO2 separation.

A chemically robust metal organic framework ZNU-2-Si with optimal pore chemistry and pore structure is reported for record C3H4 storage and C3H4/C3H6 separation by thermodynamic–kinetic synergism along with entropy–enthalpy balanced adsorption sites.

A combination of high-throughput molecular simulation and machine learning (ML) algorithms has been widely adopted to seek promising metal-organic frameworks (MOFs) as energy gas carriers. However, the currently reported studies are mainly limited to extracting top performers from existing databases, not fully unleashing the ML capabilities for intelligently predicting novel structures with better performance. Herein, an efficient self-evolutionary methodology was proposed for searching high-performance MOFs that are unstructured in the origin database, in which a Tangent Adaptive Genetic Algorithm (TAGA) was newly put forward for structural evolution and the high-precision ML model of eXtreme Gradient Boosting (XGBoost) was employed as the fitness function. By taking CH

Metal–organic frameworks (MOFs) have great potentials as adsorbents for natural gas purification. However, the trade-off between selectivity and adsorption capacity remains a challenge. Herein, we report a pillared-layer metal–organic framework Ni(HBTC)(bipy) for efficiently separating the C3H8/C2H6/CH4 mixture. The experimental results show that the adsorption capacity of C3H8 and C2H6 on Ni(HBTC)(bipy) are as high as 6.18 and 5.85 mmol·g–1,while only 0.93 mmol·g–1 for CH4 at 298 K and 100 kPa. Especially, the adsorption capacity of C3H8 at 5 kPa can reach an unprecedented 4.52 mmol·g–1 and for C2H6 it is 1.48 mmol·g–1 at 10 kPa. The ideal adsorbed solution theory predicted C3H8/CH4 selectivity is as high as 1857.0, superior to most of the reported materials. Breakthrough experiment results indicated that material could completely separate the C3H8/C2H6/CH4 mixture. Therefore, Ni(HBTC)(bipy) is a promising material for separation of natural gas.

Understanding CO2 diffusion behavior in functional nanoporous materials is beneficial for improving the CO2 adsorption, separation, and conversion performances. However, it is a great challenge for studying the diffusion process in experiments. Herein, CO2 diffusion in 962 metal–organic frameworks (MOFs) with open Cu sites was systematically investigated by theoretical methods in the combination of molecular dynamic simulations and density functional theory (DFT) calculations. A specific force field was derived from DFT-D2 method combined with Grimme's dispersion-corrected (D2) density functional to well describe the interaction energies between Cu and CO2. It is observed that the suitable topology is conductive to CO2 diffusion, and 2D-MOFs are more flexible in tuning and balancing the CO2 adsorption and diffusion behaviors than 3D-MOFs. In addition, analysis of diffusive trajectories and the residence times on different positions indicate that CO2 diffusion is mainly along with the frameworks in these MOFs, jumping from one strong adsorption site to another. It is also influenced by the electrostatic interaction of the frameworks. Therefore, the obtained information may provide useful guidance for the rational design and synthesis of MOFs with enhanced CO2 diffusion performance for specific applications.

Membrane separation is a high-efficiency, energy-saving, and environment-friendly separation technology. Covalent organic framework (COF)-based mixed-matrix membranes (MMMs) have broad application prospects in gas separation and are expected to provide new solutions for coal-bed methane purification. Herein, a high-throughput screening method is used to calculate and evaluate COF-based MMMs for CH4/N2 separation. General design rules are proposed from thermodynamic and kinetic points of view using the computation-ready, experimental COFs. From our database containing 471671 generated COFs, 5 COF membrane materials were screened with excellent membrane selectivities, which were then used as the filler of MMMs for separation performance evaluation. Among them, BAR-NAP-Benzene_CF3 combined with polydimethylsiloxane and styrene-b-butadiene-b-styrene show high CH4 permeability of 4.43×10–13 mol·m·s–1·Pa–1·m–2 and high CH4/N2 selectivity of 9.54, respectively. The obtained results may provide reasonable information for the design of COF-based membranes for the efficient separation of CH4/N2.

Discovery of remarkable porous materials for CO

Discovery of remarkable porous materials for CO2 capture from wet flue gas is of great significance to reduce the CO2 emissions, but elucidating the most critical structure features for boosting CO2 capture capabilities remains a great challenge. Here, machine learning assisted computational screening on 516 experimental covalent organic frameworks (COFs) identify the superior secondary building units (SBUs) for wet flue gas separation, which are tetraphenylporphyrin unit in sql-type COFs and functional groups. Accordingly, 1233 COFs are assembled using the superior SBUs. Combined with DFT calculations, the “electron-donating induced vdW interaction” effect is discovered to design better-performing COFs with superior CO2 uptake, which can achieve 4.4 mmol·g-1 with CO2/N2 selectivity of 104.8; while the “electron-withdrawing induced vdW+electrostatic coupling interaction” effect is proposed to design better-performing COFs with superior CO2/N2 selectivity, which can arrive 277.6 with CO2 uptake of 2.2 mmol·g-1, in this case, H2O contributes to improving the CO2/N2 selectivity.

Sulfur hexafluoride (SF6), which has a greenhouse effect of 228 000 times more terrible than carbon dioxide, has attracted increasing attention. Its efficient capture, especially from the mixtures ...

Efficient separation of the CH

To fabricate high performing ultrathin membranes, the interlayer nanochannel environment, which is hard to be observed and characterized in experiments, plays a key role in membrane performance. In...

CH4 /N2 separation is one of the great challenges in gas separation, which is of scientific and practical importance, such as in the upgrading of unconventional natural gas. Unfortunately, the separation performance is still quite low so far mainly due to their very close physical properties. In this work, a high-throughput computational screening method was performed to develop metal-organic frameworks (MOFs) for efficient CH4 /N2 separation. General designing rules as well as the correlation between selectivity and our proposed adsorbility (AD) parameter were obtained by carrying out systematic GCMC simulations of the existing 5109 CoRE MOFs. With the aid of this information, five virtual MOFs were screened out from the large database with 303 991 generated MOFs constructed in our previous work, exhibiting much higher selectivities than all the reported values. Among them, the selectivity of Zn-PYZ-BPY-1 can reach over 29.0, about 2.4 times of the highest value reported in the literature. These results may not only suggest promising candidates for CH4 /N2 separation but also provide useful information for large screening of MOFs for other specific separation mixtures.

Ionic liquid/metal–organic framework (IL/MOF) composites show great potential in CO2 capture. Here, we report a large-scale computational assembly of 550 357 IL/MOF composites for CO2/CH4 separation by developing a configurational-bias Monte Carlo (CBMC)-based incorporation method rather than applying the long-time Molecular Dynamics (MD) method. The introduction of ILs into MOFs shows both improvement and good balance of selectivity and working capacity. The results show that the high performing IL/MOF composites are mainly the wire-tube type structures originating from 1,3-dimethyl-imidazolium tetrafluoroborate [MMIM][BF4] and MOFs in sql topology with a pore size of ∼9 A, in which ILs are well confined in the MOFs to form the continuous, cation–anion alternately connected electronic nanowires. This work finds that synergistic adsorption sites can be formed in this wire-tube structure with a suitable size, providing useful information that can guide the future design of IL/MOF composites with improved CO2 capture performance.

Membrane based CO2/CH4 separation is an effective and energy saving way for highly demanded natural gas upgrading. Herein, high-throughput computational screening of covalent organic frameworks (CO...

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