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The chemical flexibility of metal-organic frameworks (MOFs) offers an ideal platform to tune structure and composition for specific applications, from gas sensing to catalysis and from photoelectric conversion to energy storage. This variability gives rise to a large configurational space that can be efficiently explored using high-throughput computational methods. In this work, we investigate from first principles the structural and electronic properties of MOF-5 variants obtained by replacing Zn with Be, Mg, Cd, Ca, Sr, and Ba and by functionalizing the originally H-passivated linkers with CH3, NO2, Cl, Br, NH2, OH, and COOH groups. To build and analyze the resulting 56 structures, we employ density-functional theory calculations embedded in an in-house developed library for automatized calculations. Our findings reveal that structural properties are mainly defined by metal atoms and large functional groups, which distort the lattice and modify coordination. The formation energy is largely influenced by functionalization and enhanced by COOH and OH groups, which promote the formation of hydrogen bonds. The charge distribution within the linker is especially influenced by functional groups with electron-withdrawing properties, while the metal nodes play a minor role. Likewise, the bandgap size is crucially determined by ligand functionalization. The smallest gaps are found with NH2 and OH groups, which introduce localized orbitals at the top of the valence band. This characteristic makes these functionalizations particularly promising for the design of MOF-5 variants with enhanced gas uptake and sensing properties. [ABSTRACT FROM AUTHOR]

When using metal–organic frameworks (MOFs) as electric field-dependent sensor devices, understanding their dielectric response is crucial as the orientation of polar groups is largely affected by confinement. To shed light on this at the molecular level, the response to a static field was computationally investigated for two structurally related MOFs, depending on their loading with guest molecules. The pillared-layer MOFs differ in their pillar moiety, with one bearing a rotatable permanent dipole moment and the other being non-polar. Two guest molecules with and without polarity, namely, methanol and methane, were considered. A comprehensive picture of the response of the guest molecules could be achieved with respect to both the amount and polarity of the confined species. For both MOFs, the dielectric response is very sensitive to the introduction of methanol, showing an anisotropic and non-linear increase in the system's relative permittivity expressed by a strongly increasing polarization response to external electric fields scaling with the number of confined methanol molecules. As expected, the effect of methane in the non-dipolar MOF is negligible, whereas subtle differences can be observed for the dipolar response of the MOF with rotatable dipolar linker groups. Taking advantage of these anisotropic and guest-molecule-specific confinement effects may open pathways for future sensing applications. Finally, methanol-induced global framework dynamics were observed in both MOFs. [ABSTRACT FROM AUTHOR]

This study introduces recommendations for conducting molecular simulations of vapor adsorption, with an emphasis on enhancing the accuracy, reproducibility, and comparability of results. The first aspect we address is consistency in the implementation of some details of typical molecular models, including tail corrections and cutoff distances, due to their significant influence on generated data. We highlight the importance of explicitly calculating the saturation pressures at relevant temperatures using methods such as Gibbs ensemble Monte Carlo simulations and illustrate some pitfalls in extrapolating saturation pressures using this method. For grand canonical Monte Carlo (GCMC) simulations, the input fugacity is usually calculated using an equation of state, which often requires the critical parameters of the fluid. We show the importance of using critical parameters derived from the simulation with the same model to ensure internal consistency between the simulated explicit adsorbate phase and the implicit bulk phase in GCMC. We show the advantages of presenting isotherms on a relative pressure scale to facilitate easier comparison among models and with experiment. Extending these guidelines to a practical case study, we evaluate the performance of various isoreticular metal–organic frameworks (MOFs) in adsorption cooling applications. This includes examining the advantages of using propane and isobutane as working fluids and identifying MOFs with a superior performance. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) are crystalline, three-dimensional structures with high surface areas and tunable porosities. Made from metal nodes connected by organic linkers, the exact properties of a given MOF are determined by node and linker choice. MOFs hold promise for numerous applications, including gas capture and storage. M2(4,4′-dioxidobiphenyl-3,3′-dicarboxylate)—henceforth simply M2(dobpdc), with M = Mg, Mn, Fe, Co, Ni, Cu, or Zn—is regarded as one of the most promising structures for CO2 capture applications. Further modification of the MOF with diamines or tetramines can significantly boost gas species selectivity, a necessity for the ultra-dilute CO2 concentrations in the direct-air capture of CO2. There are countless potential diamines and tetramines, paving the way for a vast number of potential sorbents to be probed for CO2 adsorption properties. The number of amines and their configuration in the MOF pore are key drivers of CO2 adsorption capacity and kinetics, and so a validation of computational prediction of these quantities is required to suitably use computational methods in the discovery and screening of amine-functionalized sorbents. In this work, we study the predictive accuracy of density functional theory and related calculations on amine loading and configuration for one diamine and two tetramines. In particular, we explore the Perdew–Burke–Ernzerhof (PBE) functional and its formulation for solids (PBEsol) with and without the Grimme-D2 and Grimme-D3 pairwise corrections (PBE+D2/3 and PBEsol+D2/3), two revised PBE functionals with the Grimme-D2 and Grimme-D3 pairwise corrections (RPBE+D2/3 and revPBE+D2/3), and the nonlocal van der Waals correlation (vdW-DF2) functional. We also investigate a universal graph deep learning interatomic potential's (M3GNet) predictive accuracy for loading and configuration. These results allow us to identify a useful screening procedure for configuration prediction that has a coarse component for quick evaluation and a higher accuracy component for detailed analysis. Our general observation is that the neural network-based potential can be used as a high-level and rapid screening tool, whereas PBEsol+D3 gives a completely qualitatively predictive picture across all systems studied, and can thus be used for high accuracy motif predictions. We close by briefly exploring the predictions of relative thermal stability for the different functionals and dispersion corrections. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable energy solutions, the development of materials with efficient hydrogen and methane storage capacities is imperative, particularly for advancing hydrogen-powered vehicles. Metal–organic frameworks (MOFs) have emerged as promising candidates to meet the stringent targets set by the Department of Energy for both hydrogen and methane storage. This study employs Grand Canonical Monte Carlo simulations to investigate the usable hydrogen and methane gravimetric and volumetric storage capacities of the recently synthesized SIGSUA. A comparative analysis encompasses the selected MOFs with similar metal compositions, those with comparable density and average pore radius, and classical benchmarks, such as IRMOF-15 and IRMOF-20, all evaluated at room temperature and moderate pressures ranging from 25 to 35 MPa. The results reveal that SIGSUA demonstrates noteworthy gravimetric and volumetric storage capacities for both hydrogen and methane, rivaling or surpassing those of the selected MOFs for analysis. These findings underscore the potential of SIGSUA in advancing clean energy storage technologies. [ABSTRACT FROM AUTHOR]

While computational screening with density functional theory (DFT) is frequently employed for the screening of metal–organic frameworks (MOFs) for gas separation and storage, commonly applied generalized gradient approximations (GGAs) exhibit self-interaction errors, which hinder the predictions of adsorption energies. We investigate the Hubbard U parameter to augment DFT calculations for full periodic MOFs, targeting a more precise modeling of gas molecule–MOF interactions, specifically for N2, CO2, and O2. We introduce a calibration scheme for the U parameter, which is tailored for each MOF, by leveraging higher-level calculations on the secondary building unit (SBU) of the MOF. When applied to the full periodic MOF, the U parameter calibrated against hybrid HSE06 calculations of SBUs successfully reproduces hybrid-quality calculations of the adsorption energy of the periodic MOF. The mean absolute deviation of adsorption energies reduces from 0.13 eV for a standard GGA treatment to 0.06 eV with the calibrated U, demonstrating the utility of the calibration procedure when applied to the full MOF structure. Furthermore, attempting to use coupled cluster singles and doubles with perturbative triples calculations of isolated SBUs for this calibration procedure shows varying degrees of success in predicting the experimental heat of adsorption. It improves accuracy for N2 adsorption for cases of overbinding, whereas its impact on CO2 is minimal, and ambiguities in spin state assignment hinder consistent improvements of O2 adsorption. Our findings emphasize the limitations of cluster models and advocate the use of full periodic MOF systems with a calibrated U parameter, providing a more comprehensive understanding of gas adsorption in MOFs. [ABSTRACT FROM AUTHOR]

The direct conversion of methane to methanol has attracted increasing interest due to abundant and low-cost natural gas resources. Herein, by anchoring Cr-oxo/-oxyhydroxides on UiO-66 metal–organic frameworks, we demonstrate that reactive anionic oxyl radicals can be formed by controlling the coordination environment based on the results of density functional theory calculations. The anionic oxyl radicals produced at the completely oxidized CrVI site acted as the active species for facile methane activation. The thermodynamically stable CrVI-oxo/-oxyhydroxides with the anionic oxyl radicals catalyze the activation of the methane C–H bond through a homolytic mechanism. An analysis of the results showed that the catalytic performance of the active oxyl species correlates with the reaction energy of methane activation and H adsorption energies. Following methanol formation, N2O can regenerate the active sites on the most stable CrVI oxyhydroxides, i.e., the Cr(O)4Hf species. The present study demonstrated that the anionic oxyl radicals formed on the anchored CrVI oxyhydroxides by tuning the coordination environment enabled facile methane activation and facilitated methanol production. [ABSTRACT FROM AUTHOR]

Polymers, known for their lightweight, high strength, and ease of processing, serve as a key component in engineering materials. Polymers with high thermal conductivity (TC) present enormous potential applications in thermal management for high-performance electronic devices. However, the discovery of thermally conductive polymers is still in a time-consuming and labor-intensive trial-and-error process, which undoubtedly hinders the progress in related applications. Fortunately, machine learning (ML) enables to overcome this obstacle by building precise models to predict the TC of polymers through learning from a large volume of data and it can quickly identify polymers with high TC and provide significant insights to guide further design and innovation. In this mini review, we briefly describe the general process of using ML to predict polymers with high TC and then give guidance for the selection and utilization of three important components: database, descriptor, and algorithm. Furthermore, we summarize the predicted thermally conductive single polymer chains, amorphous polymers, and metal-organic frameworks via ML and identify the key factors that lead to high TC. Finally, we touch on the challenges faced when utilizing ML to predict the TC of polymer and provide a foresight into future research endeavors. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs), with their unique porous structures and versatile functionality, have emerged as promising materials for the adsorption, separation, and storage of diverse molecular species. In this study, we investigate water adsorption in MOF-808, a prototypical MOF that shares the same secondary building unit (SBU) as UiO-66, and elucidate how differences in topology and connectivity between the two MOFs influence the adsorption mechanism. To this end, molecular dynamics simulations were performed to calculate several thermodynamic and dynamical properties of water in MOF-808 as a function of relative humidity (RH), from the initial adsorption step to full pore filling. At low RH, the μ3-OH groups of the SBUs form hydrogen bonds with the initial water molecules entering the pores, which triggers the filling of these pores before the μ3-OH groups in other pores become engaged in hydrogen bonding with water molecules. Our analyses indicate that the pores of MOF-808 become filled by water sequentially as the RH increases. A similar mechanism has been reported for water adsorption in UiO-66. Despite this similarity, our study highlights distinct thermodynamic properties and framework characteristics that influence the adsorption process differently in MOF-808 and UiO-66. [ABSTRACT FROM AUTHOR]

Despite the intense activity at electronic and atomistic resolutions, coarse grained (CG) modeling of metal–organic frameworks remains largely unexplored. One of the main reasons for this is the lack of adequate CG force fields. In this work, we present iterative Boltzmann inversion and force matching (FM) force fields for modeling ZIF-8 at three different coarse grained resolutions. Their ability to reproduce structure, elastic tensor, and thermal expansion is evaluated and compared with that of MARTINI force fields considered in previous work [Alvares et al., J. Chem. Phys. 158, 194107 (2023)]. Moreover, MARTINI and FM are evaluated for their ability to depict the swing effect, a subtle phase transition ZIF-8 undergoes when loaded with guest molecules. Overall, we found that all our force fields reproduce structure reasonably well. Elastic constants and volume expansion results are analyzed, and the technical and conceptual challenges of reproducing them are explained. Force matching exhibits promising results for capturing the swing effect. This is the first time these CG methods, widely applied in polymer and biomolecule communities, are deployed to model porous solids. We highlight the challenges of fitting CG force fields for these materials. [ABSTRACT FROM AUTHOR]

In this study, we used a high-throughput computational screening approach to examine the potential of metal–organic frameworks (MOFs) for capturing propane (C3H8) from different gas mixtures. We focused on Quantum MOF (QMOF) database composed of both synthesized and hypothetical MOFs and performed Grand Canonical Monte Carlo (GCMC) simulations to compute C3H8/N2/O2/Ar and C3H8/C2H6/CH4 mixture adsorption properties of MOFs. The separation of C3H8 from air mixture and the simultaneous separation of C3H8 and C2H6 from CH4 were studied for six different adsorption-based processes at various temperatures and pressures, including vacuum-swing adsorption (VSA), pressure-swing adsorption (PSA), vacuum–temperature swing adsorption (VTSA), and pressure-temperature swing adsorption (PTSA). The results of molecular simulations were used to evaluate the MOF adsorbents and the type of separation processes based on selectivity, working capacity, adsorbent performance score, and regenerability. Our results showed that VTSA is the most effective process since many MOFs offer high regenerability (>90%) combined with high C3H8 selectivity (>7 × 103) and high C2H6 + C3H8 selectivity (>100) for C3H8 capture from air and natural gas mixtures, respectively. Analysis of the top MOFs revealed that materials with narrow pores (<10 Å) and low porosities (<0.7), having aromatic ring linkers, alumina or zinc metal nodes, typically exhibit a superior C3H8 separation performance. The top MOFs were shown to outperform commercial zeolite, MFI for C3H8 capture from air, and several well-known MOFs for C3H8 capture from natural gas stream. These results will direct the experimental efforts to the most efficient C3H8 capture processes by providing key molecular insights into selecting the most useful adsorbents. [ABSTRACT FROM AUTHOR]

This study explores the nature, dynamics, and reactivity of the photo-induced charge separated excited state in a Fe3+-doped titanium-based metal organic framework (MOF), xFeMIL125-NH2, as a function of iron concentration. The MOF is synthesized with doping levels x = 0.5, 1 and 2 Fe node sites per octameric Ti-oxo cluster and characterized by powder x-ray diffraction, UV-vis diffuse reflectance, atomic absorption, and steady state Fe K-edge X-ray absorption spectroscopy. For each doping level, time-resolved X-ray transient absorption spectroscopy studies confirm the electron trap site role of the Fe sites in the excited state. Time scan data reveal multiexponential decay kinetics for the charge recombination processes which extend into the microsecond range for all three concentrations. A series of dye photodegradation studies, based on the oxidative decomposition of Rhodamine B, demonstrates the reactivity of the charge separated excited state and the photocatalytic capacity of these MOF materials compared to traditional heterometal-doped semiconductor photocatalysts. [ABSTRACT FROM AUTHOR]

Hydrophobicity has proven fundamental in an inexhaustible amount of everyday applications. Material hydrophobicity is determined by chemical composition and geometrical characteristics of its macroscopic surface. Surface roughness or texturing enhances intrinsic hydrophilic or hydrophobic characteristics of a material. Here we consider crystalline surfaces presenting molecular-scale texturing typical of crystalline porous materials, e.g., metal-organic frameworks. In particular, we investigate one such material with remarkable hydrophobic qualities, ZIF-8. We show that ZIF-8 hydrophobicity is driven not only by its chemical composition but also its sub-nanoscale surface corrugations, a physical enhancement rare amongst hydrophobes. Studying ZIF-8's hydrophobic properties is challenging as experimentally it is difficult to distinguish between the materials' and the macroscopic corrugations' contributions to the hydrophobicity. The computational contact angle determination is also difficult as the standard "geometric" technique of liquid nanodroplet deposition is prone to many artifacts. Here, we characterise ZIF-8 hydrophobicity via: (i) the "geometric" approach and (ii) the "energetic" method, utilising the Young–Dupré formula and computationally determining the liquid–solid adhesion energy. Both approaches reveal nanoscale Wenzel-like bathing of the corrugated surface. Moreover, we illustrate the importance of surface linker termination in ZIF-8 hydrophobicity, which reduces when varied from sp3 N to sp2 N termination. We also consider halogenated analogues of the methyl-imidazole linker, which promote the transition from nanoWenzel-like to nanoCassie–Baxter-like states, further enhancing surface hydrophobicity. Present results reveal the complex interface physics and chemistry between water and complex porous, molecular crystalline surfaces, providing a hint to tune their hydrophobicity. [ABSTRACT FROM AUTHOR]

The liquid-to-vapor transition can occur under unexpected conditions in nanopores, opening the door to fundamental questions and new technologies. The physics of boiling in confinement is progressively introduced, starting from classical nucleation theory, passing through nanoscale effects, and terminating with the material and external parameters that affect the boiling conditions. The relevance of boiling in specific nanoconfined systems is discussed, focusing on heterogeneous lyophobic systems, chromatographic columns, and ion channels. The current level of control of boiling in nanopores enabled by microporous materials such as metal organic frameworks and biological nanopores paves the way to thrilling theoretical challenges and to new technological opportunities in the fields of energy, neuromorphic computing, and sensing. [ABSTRACT FROM AUTHOR]

Many-Body eXpansion (MBX) is a C++ library that implements many-body potential energy functions (PEFs) within the "many-body energy" (MB-nrg) formalism. MB-nrg PEFs integrate an underlying polarizable model with explicit machine-learned representations of many-body interactions to achieve chemical accuracy from the gas to the condensed phases. MBX can be employed either as a stand-alone package or as an energy/force engine that can be integrated with generic software for molecular dynamics and Monte Carlo simulations. MBX is parallelized internally using Open Multi-Processing and can utilize Message Passing Interface when available in interfaced molecular simulation software. MBX enables classical and quantum molecular simulations with MB-nrg PEFs, as well as hybrid simulations that combine conventional force fields and MB-nrg PEFs, for diverse systems ranging from small gas-phase clusters to aqueous solutions and molecular fluids to biomolecular systems and metal-organic frameworks. [ABSTRACT FROM AUTHOR]

Atomic description of electrochemical systems requires reactive interaction potential to explicitly describe the chemistry between atoms and molecules and the evolving charge distribution and polarization effects. Calculating Coulomb electrostatic interactions and polarization effects requires a better estimate of the partial charge distribution in molecular systems. However, models such as reactive force fields and charge equilibration (QEq) include Coulomb interactions up to a short-distance cutoff for better computational speeds. Ignoring long-distance electrostatic interaction affects the ability to describe electrochemistry in large systems. We studied the long-range Coulomb effects among charged particles and extended the QEq method to include long-range effects. By this extension, we anticipate a proper account of Coulomb interactions in reactive molecular dynamics simulations. We validate the approach by computing charges on a series of metal-organic frameworks and some simple systems. Results are compared to regular QEq and quantum mechanics calculations. The study shows slightly overestimated charge values in the regular QEq approach. Moreover, our method was combined with Ewald summation to compute forces and evaluate the long-range effects of simple capacitor configurations. There were noticeable differences between the calculated charges with/without long-range Coulomb interactions. The difference, which may have originated from the long-range influence on the capacitor ions, makes the Ewald method a better descriptor of Coulomb electrostatics for charged electrodes. The approach explored in this study enabled the atomic description of electrochemical systems with realistic electrolyte thickness while accounting for the electrostatic effects of charged electrodes throughout the dielectric layer in devices like batteries and emerging solid-state memory. [ABSTRACT FROM AUTHOR]

We use 2H nuclear magnetic resonance (NMR) to study water (D2O) reorientation and diffusion in the metal–organic framework MFU-4l, which features a regular three-dimensional network of nearly spherical pores with diameters of 1.2 and 1.9 nm. We observe that the rotational correlation times follow Vogel–Fulcher–Tammann and Arrhenius (Ea = 0.48 eV) relations above ∼225 K and below ∼170 K, respectively, whereas the temperature dependence continuously evolves from one to the other behavior in the broad crossover zone in between. In the common temperature range, the present NMR results are fully consistent with previous broadband dielectric spectroscopy (BDS) data on water (H2O) in a very similar framework. Several of our observations, e.g., rotational–translational coupling, indicate that a bulk-like structural (α) relaxation is observed above the crossover region. When cooling through the crossover zone, a quasi-isotropic reorientation mechanism is retained, while 2H spin-lattice relaxation evolves from exponential to nonexponential, implying that the water dynamics probed at low temperatures does no longer fully restore ergodicity on the time scale of this experiment. We discuss that the latter effect may result from bulk-like and/or confinement-imposed spatially heterogeneous water properties. Comparison with previous NMR and BDS results for water in other confinements reveals that, for confinement sizes around 2 nm, water reorientation depends more on the pore diameter than on the pore chemistry, while water diffusion is strongly affected by the connectivity and topology of the pores. [ABSTRACT FROM AUTHOR]

We report APW+lo (augmented plane wave plus local orbital) density functional theory (DFT) calculations of large molecular systems using the domain specific SIRIUS multi-functional DFT package. The APW and FLAPW (full potential linearized APW) task and data parallelism options and the advanced eigen-system solver provided by SIRIUS can be exploited for performance gains in ground state Kohn–Sham calculations on large systems. This approach is distinct from our prior use of SIRIUS as a library backend to another APW+lo or FLAPW code. We benchmark the code and demonstrate performance on several magnetic molecule and metal organic framework systems. We show that the SIRIUS package in itself is capable of handling systems as large as a several hundred atoms in the unit cell without having to make technical choices that result in the loss of accuracy with respect to that needed for the study of magnetic systems. [ABSTRACT FROM AUTHOR]

We present a Raman scattering spectroscopic study of boron imidazolate metal-organic frameworks (BIFs) with three different magnetic metal ions and one non-magnetic in a wide frequency range from 25 to 1700 cm−1, which covers local vibrations of the imidazolate linkers as well as collective lattice vibrations. We show that the spectral region above 800 cm−1 belongs to the local vibrations of the linkers, which have the same frequencies for the studied BIFs without any dependence on the structure of the BIFs and are easily interpreted based on the spectra of imidazolate linkers. In contrast, collective lattice vibrations, observed below 100 cm−1, show a distinction between cage and two-dimensional BIFs structures, with a weak dependence on the metal node. We identify the range of vibrations around 200 cm−1, which are distinct for each metal-organic framework, depending on a metal node. Our work demonstrates the energy hierarchy in the vibrational response of BIFs. [ABSTRACT FROM AUTHOR]

In this contribution, the well-known MARTINI particle-based coarse graining approach is tested for its ability to model the ZIF-8 metal-organic framework. Its capability to describe structure, lattice parameters, thermal expansion, elastic constants and amorphization is evaluated. Additionally, the less coarsened models were evaluated for reproducing the swing effect and the host–guest interaction energies were analyzed. We find that MARTINI force fields successfully capture the structure of the Metal-Organic Framework (MOF) for different degrees of coarsening, with the exception of the MARTINI 2.0 models for the less coarse mapping. MARTINI 2.0 models predict more accurate values of C11 and C12, while MARTINI 3.0 has a tendency to underestimate them. Among the possibilities tested, the choice of bead flavors within a particular MARTINI version appears to have a less critical impact in the simulated properties of the empty framework. None of the coarse-grained (CG) models investigated were able to capture the amorphization nor the swing effect within the scope of MD simulations. A perspective on the importance of having a proper Lennard-Jones (LJ) parametrization for modeling guest–MOF and MOF–MOF interactions is highlighted. [ABSTRACT FROM AUTHOR]

In recent years, metal-organic frameworks, in general, and zeolitic imidazolate frameworks, in special, had become popular due to their large surface area, pore homogeneity, and easy preparation and integration with plasmonic nanoparticles to produce optical sensors. Herein, we summarize the late advances in the use of these hybrid composites in the field of surface-enhanced Raman scattering and their future perspectives. [ABSTRACT FROM AUTHOR]

The potential of microbial fuel cell (MFC) technology to generate electricity simultaneously with treating organic and inorganic has gained importance, recently. The efficiency of the MFC system varies according to the types of MFCs, types, and areas of electrodes, separators, substrate, etc ... In this study, a dual-chamber (H-type, membrane separator) MFC system was set up and used for electricity production from animal manure. A copper-based metal organic framework (Cu-MOF) was synthesized and used in a polyvinylidene fluoride (PVDF) membrane matrix. The water uptake (WU) value, mechanical strength, and cation exchange capacity (CEC) of the membranes were investigated. MFC performances of the pristine and Cu-MOF incorporated nanocomposite membranes were also performed. Effects of the Cu-MOF ratio (from 1 to 4 wt percentage), the operating time, and external resistance on voltage output and power density were evaluated. As a result, the incorporation of Cu-MOF enhanced the CEC from 1.04 mmol/g to 1.77 mmol/g, and the mechanical strength from 0.55 MPa to 1.15 MPa. The highest power density value was obtained as 4.62 mW/m2 by using 3 wt% of Cu-MOF loaded membrane. • H-type MFC was set up and used for electricity production from animal manure. • Polyvinylidene fluoride (PVDF) membranes with and without Cu-MOF were produced. • The incorporation of Cu-MOF enhanced the CEC from 1.04 mmol/g to 1.77 mmol/g. • The highest power density of 4.62 mW/m2 obtained using 3 wt% Cu-MOF membrane. [ABSTRACT FROM AUTHOR]

This research investigates the synthesis and photocatalytic performance of MM-MOFs based on porphyrin ligands for the conversion of 1,5-DHN to Juglone. This conversion is significant as Juglone serves as a crucial building block in anthraquinone synthesis. MM-MOFs have shown enhanced properties than their monometallic counterparts. In this research, the substitution of the second metal ions in the inorganic nodes will allow the bimetallic system to show synergistic effects and increase the photocatalytic activity. MM-MOFs, in which multifunctional organic linkers (such as porphyrins) are utilized, exhibit superior performance compared to single-functional linkers. Photocatalytic reactions were conducted using varying molar ratios of cobalt and nickel as nodes, and H2TCPP and Mn-TCPP as linkers. The highest photocatalytic efficiency of 69% was achieved using a molar ratio of 1:1 of Co:Ni and Mn-TCPP (Ni50%/Co50% TCPP-Mn), thereby showcasing a synergistic effect between Co:Ni as nodes and Mn-porphyrin as the linker. The synthesized MM-MOFs were extensively characterized using techniques such as FTIR, SEM, BET, XRD, DRS, EDX, XPS and TEM. Additionally, various factors influencing photocatalytic activity, including solvent, oxidant, time and light source were optimized. The best results confirm that acetonitrile as the solvent, 8 mg of MOF, oxygen as the oxidant, a reaction time of 4 h and a Xenon lamp as the light source. The outcomes of this study demonstrate the innovative potential of MM-MOFs as efficient photocatalysts for converting 1,5-DHN to Juglone, with broader implications for applications in catalysis. [ABSTRACT FROM AUTHOR]

Recycling waste polyethylene terephthalate (PET) bottles into value-added ligand materials for synthesizing metal-organic frameworks (MOFs) derived catalysts is an eco-friendly and economically viable process. The waste PET bottles were readily broken down into 1,4-benzenedicarboxylic acid (BDC) ligands in a highly alkaline environment. Herein, we fabricated a Co@Cr(OH) 3 /ZrO 2 catalyst via the carbonization of PET-derived UiO-66 metal-organic frameworks for the catalytic dehydrogenation of formic acid at low temperatures. The as-prepared Co@Cr(OH) 3 /ZrO 2 catalyst provides a turnover frequency of 7685 h−1 for hydrogen generation (120 mL in 1.5 min) at ambient temperature. This is due to the uniform dispersion of the fine metal nanoparticle (NPs) (Co NPs, ∼3.75 nm) and the synergistic effect of the Co NPs and Cr(OH) 3 /ZrO 2 supports. In addition, the characterization results indicate that porous Zr-MOFs may effectively enclose tiny particles, which is favorable for enhanced dehydrogenation performance. In addition, the Co@Cr(OH) 3 /ZrO 2 catalysts demonstrated excellent stability against aggregation and were recyclable over seven cycles without any significant catalytic loss. Thus, this study provides a sustainable methodology for the development of MOF-derived, effective, and stable catalysts for formic acid dehydrogenation towards hydrogen production. [ABSTRACT FROM AUTHOR]

Tissue engineering applications in bone defect treatment have shown promising outcomes over the past decade. In this context, taking advantage of bioactive scaffolds mimicking the intrinsic composition of bone has resulted in remarkable effects on bone regeneration. In this study, Zirconium-based metal-organic framework, known as MOF 801, was synthesized and incorporated into the gelatin matrix as an osteoconductive agent to fabricate a nanocomposite bone scaffold by freeze-drying method. Physical and chemical characteristics of MOF 801 and nanocomposite scaffolds were analyzed using FE-SEM, EDS, XRD, ICP and FTIR. Besides, the biological activity of the prepared scaffolds was evaluated by MTT, alizarin red staining, crystal violet staining, and ALP assays. Inclusion of MOF 801 NPs into the scaffolds resulted in enhancement of their compressive strength up to 15 ± 0.05 MPa. The nanocomposite samples containing MOF 801 NPs also exhibited favorable bioactive feature that was confirmed by their apatite-forming ability on their surfaces upon immersion in SBF solution. The Zr ion and fumarate release studies illustrated sustained release profiles from the gelatin matrix, leading to both antioxidant and anti-inflammatory properties. MTT assay results affirmed biocompatibility of scaffolds containing up to 5 % w/w MOF 801, besides the crystal violet assay exhibited proper cell confluency and adhesion. Eventually, Alizarin red and ALP activity assays revealed that an increment of MOF 801 could induce calcium mineralization and Alkaline Phosphatase enzyme production in MG-63 cells confirming the potential of prepared scaffolds for related bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

Acetone, a flammable and volatile liquid, is toxic and can affect human well-being. Additionally, its presence in exhaled air can indicate the state of human respiratory health. Therefore, the investigation of an acetone gas sensor holds significant urgency in the realm of scientific research. Metal-organic frameworks (MOFs) exhibit significant promise in the field of gas detection due to their extensive surface areas, remarkable porosity, and the inclusion of unsaturated metallic sites. The study conducted the preparation of ErFeO 3 /α-Fe 2 O 3 nanocomposites through impregnation and oxidation roasting methods. EF21 (M Er (NO 3) 3 ∙ 6 H 2 O :M MIL-100(Fe) = 2:1) exhibited a large surface area of 43.7 m2/g and a high abundant oxygen vacancy of 12.5 %. Gas sensing experiments revealed that the EF21-based gas sensor exhibited a strong response of 55 towards 100 ppm acetone, with a low detection limit of 2 ppm (S = 3.3). Notably, the sensor demonstrated excellent selectivity towards acetone over other volatile organic compounds (e.g., ethanol, methanol, ammonia, ether, and toluene) in gas selectivity tests. Moreover, the EF21-based gas sensor maintained its responsiveness to acetone even under high relative humidity conditions (RH:90 %, S = 27) and demonstrated stability over a 15-day long-term test. The study provided a comprehensive explanation of the gas sensing mechanism responsible for the enhanced performance observed in ErFeO 3 /α-Fe 2 O 3 through detailed analyses. [ABSTRACT FROM AUTHOR]

[Display omitted] Volatile organic compounds (VOCs) have always been a major concern as a global environmental problem. As a low-cost, high-efficiency and visual sensor, photonic crystals (PCs) have been actively studied in VOCs detection. Herein, a one-dimensional PC sensor for visual sensing of highly toxic benzene series VOC vapors is prepared for the first time by integrating a new photo-crosslinked polymer-poly(styrene-benzoylphenyl acrylate) P(St-BPA) and a high specific surface area metal–organic framework (MOF) MIL-101(Cr). The PC can detect VOCs quantitatively and visually, and clearly distinguish 7 benzene series vapors. The detection limit of the benzene series VOCs is as low as 0.06–3.45 g/m3. Meanwhile, owing to the ultra-thin layer and porous structure, the PC can reach a response equilibrium to the VOCs within 1–2.6 s. Moreover, the PC has a good organic vapor tolerance and can maintain stable optical performance after 1000 times of reuse in VOCs. Besides, 4 other PCs assembled with different aryl polymers and MOFs are first fabricated and their sensing performance to benzene series VOCs are studied and compared, which provides a valuable reference for the selection of materials for the preparation of such PC sensors. [ABSTRACT FROM AUTHOR]

An efficient 3D bifunctional nanofiber electrocatalyst with synergistic multiple active sites for high-performance aqueous/solid ZABs was developed by electrospinning and MOF/COF in-situ growth strategy. [Display omitted] Covalent organic frameworks (COFs) and metal–organic frameworks (MOFs) have attracted growing attention in electrochemical energy storage and conversion systems (e.g., Zn-air batteries, ZABs) owing to their structural tunability, ordered porosity and high specific surface area. In this work, for the first time, the three-dimensional (3D) highly open catalyst (CNFs/CoZn-MOF@COF) possessing hierarchical porous structure and high-density active sites of uniform cobalt (Co) nanoparticles and metal-N x (M-N x , M = Co and Zn) is demonstrated, which is fabricated using electrospinning technique in combination with MOF/COF hybridization strategy and direct pyrolysis. Benefiting from the well-designed branch-leaf nanostructures, plentiful and uniform active sites on the MOF/COF-derived carbon frameworks, as well as the synergistic effect of multiple active sites, CNFs/CoZn-MOF@COF catalyst achieves superior electrocatalytic activity and stability towards both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with a small potential gap (ΔE = 0.75 V). In situ Raman spectroscopy and X-ray photoelectron spectroscopy results indicate that the CoOOH intermediates are the main active species during OER/ORR. Significantly, both aqueous and all-solid-state rechargeable ZABs assembled with CNFs/CoZn-MOF@COF as the air cathode show high open-circuit potential, outstanding peak power density, large capacity and long cycle life. More impressively, the obtained all-solid-state ZAB also displays superb mechanical flexibility and device stability under different, showcasing great application deformations potential in portable and wearable electronics. This work provides a new insight into the design and exploitation of bifunctional catalysts from MOF/COF hybrid materials for energy storage and conversion devices. [ABSTRACT FROM AUTHOR]

[Display omitted] Melamine-based metal–organic frameworks (MOFs) for high-performance supercapacitor applications are described in this paper. Melamine (Me) is employed as an organic linker, and three metal ions cobalt, nickel, and iron (Co, Ni, Fe) are used as central metal ions to manufacture the desired MOF materials (Co-Me, Ni-Me, and Fe-Me). While melamine is an inexpensive organic linker for creating MOF materials, homogenous molecular structures can be difficult to produce. The most effective technique for expanding the molecular structures of MOFs through suitable experimental optimization is used in this work. The MOFs materials are characterized using standard techniques. The kinetics of the materials' reactions are investigated using attenuated total reflectance. X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (P-XRD), Fourier transform infrared (ATR-FT-IR) spectroscopy, and Brunauer–Emmett–Teller (BET) studies verified the development of the MOFs structure. The surface morphology of the produced materials is investigated using field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and atomic force microscopy (AFM). The elements found in MOFs are studied via XPS analysis, energy dispersive X-ray diffraction (EDX), mapping, and mapping. The materials' absorption characteristics were examined by the use of UV–visible absorption spectroscopy. The thermal stability of the materials is examined by thermogravimetric analysis (TGA); these materials are more stable, according to the findings, even at high temperatures. The electrochemical investigation determines the specific capacitance of the materials. The specific capacitance of Co-Me, Ni-Me, and Fe-Me in 3 M KOH electrolyte is 1267.36, 803.22, and 507.59F/g @ 1 A-1, according to the three-electrode arrangement. The two-electrode device maximizes power and energy density by using an asymmetrical supercapacitor in a 3 M KOH electrolyte. The power and energy densities of Co-Me, Ni-Me, and Fe-Me are 3650.63, 2813.21, and 6210.45 W kg−1, and 68.43, 46.32, and 42.2 Wh kg−1, respectively. According to the materials stability test, the MOFs are highly stable after 10,000 cycles. Preliminary results suggest that the materials are suitable for usage in high-end supercapacitor uses. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The organic cocrystal strategy has provided a convenient and efficient platform for preparing organic photothermal materials. However, the rapidly directional preparation of cocrystals with desirable photothermal properties remains challenging due to a lack of suitable design ideas. Here, two new photothermal cocrystals, MTC and MFC, based on acceptor molecules (TCNQ and F4TCNQ) with different electron‐withdrawing capacities were quickly prepared by the coprecipitation method, aiming to explore the effect of charge transfer (CT) interaction on photothermal properties. Compared with MTC, the stronger intermolecular CT interaction in MFC facilitates extending the absorption range (from the NIR‐I to the NIR‐II region) and enhancing the non‐radiative transition process. Under the 808 nm laser irradiation, the photothermal conversion efficiency (PCE) of MFC is 54.6%, whereas MTC displays a mere 36.8%. The MFC cocrystal was further combined with a flexible polymer substrate (HPDMS) to prepare a flexible wearable heater (HPDMS@MFC), which exhibits excellent NIR‐II photothermal performance. This work points out a research direction for the rapid assembly of efficient photothermal cocrystals and additionally provides an extensive application prospect for organic photothermal cocrystals in the field of wearable devices. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) are regarded as the promising potential photocatalytic materials because of its high specific surface area, regular morphology and highly adjustable structure. Herein, introducing different addition percentage of 1-vinylimidazole to two-dimensional zeolite imidazole framework (ZIF-L) with leaf-shaped morphology was successfully prepared via water-assisted strategy and applied in the photocatalytic hydrogen evolution experiments. The results indicate that VZ-12 shows the highest photocatalytic activity with hydrogen production rate of 162.7 μmol g−1 h−1, which is 3 times than that in VZ-0 (pure ZIF-L, 56.33 μmol g−1 h−1) under simulated sunlight. The enhanced performance is ascribed to the increased specific surface area observed via BET, narrow band gap (E g) explored through UV–vis DRS and decreased recombination of photo-generated charge carriers measured by photoluminescence (PL). In a word, the effort of our study provides a new idea for developing and fabricating efficient hydrogen production photocatalyst via water splitting. [Display omitted] • Introducing 1-vinylimidazole to ZIF-L lattice realizes the transformation from ZIF-L phase to ZIF-8 phase. • Suitable addition of 1-vinylimidazole acquires the higher specific surface area and provides the more active sites for photocatalysis. • Different organic ligands complexing with Zn2+ narrow the band gap and reduce the recombination of photo-generated charge carriers. • 1-vinylimidazole modified ZIF-L exhibits strong hydrogen evolution performance. [ABSTRACT FROM AUTHOR]

A novel metal–organic framework based on octa-nuclear zinc clusters, namely [Zn4(L)(OH)2(H2O)4] (Zn-MOF) (H6L = hexakis(4-carboxylatophenoxy)cyclotriphosphazene), has been synthesized and structurally characterized by a solvothermal method. Single-crystal X-ray diffraction shows that eight zinc ions form a linear octa-nuclear cluster via a μ3-OH group, and each hexakis(4-carboxylatophenoxy)-cyclotriphosphazene connects four octa-nuclear clusters to construct 3D frameworks with one-dimensional pore structures. Zn-MOF exhibits suitable fluorescence properties, water stability as well as thermal stability, and can be applied as a convenient fluorescent probe for the detection of radioactive uranyl cations (UO22+) and ferric ions (Fe3+) through fluorescence quenching behavior. The corresponding Ksv values can reach 7.44 × 103 M−1 and 1.49 × 104 M−1. Meanwhile, the theoretical calculations fully indicated that the introduction of UO22+ effectively inhibited the metal-to-ligand charge transfer (MLCT) of Zn-MOF, which in turn led to the fluorescence quenching phenomenon. Therefore, Zn-MOF prepared using crystal engineering can be used to construct an efficient and reliable fluorescent probe used in the fields of environmental monitoring and nuclear waste treatment. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have emerged as promising electrode materials for supercapacitors (SCs) due to their highly porous structures, tunable chemical compositions, and diverse morphologies. However, their applications are hindered by low conductivity and poor cycling performance. A novel approach for resolving this issue involves the growth of layered double hydroxides (LDHs) using MOFs as efficient templates or precursors for electrode material preparation. This method effectively enhances the stability, electrical conductivity, and mass transport ability of MOFs. The MOF-derived LDH exhibits a well-defined porous micro-/nano-structure, facilitating the dispersion of active sites and preventing the aggregation of LDHs. Firstly, this paper introduces synthesis strategies for converting MOFs into LDHs. Subsequently, recent research progress in MOF-derived LDHs encompassing pristine LDH powders, LDH composites, and LDH-based arrays, along with their applications in SCs, is overviewed. Finally, the challenges associated with MOF-derived LDH electrode materials and potential solutions are discussed. [ABSTRACT FROM AUTHOR]

The increasing CO2 emissions and their direct impact on climate change due to the greenhouse effect are environmental issues that must be solved as soon as possible. Metal–organic frameworks (MOFs) are one class of crystalline adsorbent materials that are thought to have enormous potential in CO2 capture applications. In this research, the effect of changing the metal center between Zr(IV), Ce(IV), and Hf(IV), and the linker between BDC and PDC has been fully studied. Thus, the six UiO-66 isoreticular derivatives have been synthesized and characterized by FTIR, PXRD, TGA, and N2 adsorption. We also report the BET surface area, CO2 adsorption capacities, kinetics, and the adsorption isosteric heat (Qst) of the UiO-66 derivatives mentioned family. The CO2 adsorption kinetics were evaluated using pseudo-first order, pseudo-second order, Avrami's kinetic models, and the rate-limiting step with Boyd's film diffusion, interparticle diffusion, and intraparticle diffusion models. The isosteric heats of CO2 adsorption using various MOFs are in the range 20–65 kJ mol−1 observing differences in adsorption capacities between 1.15 and 4.72 mmol g−1 at different temperatures due to the electrostatic interactions between CO2 and extra-framework metal ions. The isosteric heat of adsorption calculation in this report, which accounts for the unexpectedly high heat released from Zr-UiO-66-PDC, is finally represented as an increase in the interaction of CO2 with the PDC linker and an increase in Qst with defects. [ABSTRACT FROM AUTHOR]

A hydrogen-bonded three-dimensional porous metal–organic framework [Mg(H2PCD)2(H2O)2]·2H2O (denoted as Mg-MOF·2H2O; H3PCD = 9-(2-(ethoxy(hydroxy)phosphonyl)ethyl)-9H-carbazole-3,6-dicarboxylic acid) was synthesized by the reactions of H3PCD and Mg(II) under solvothermal conditions. The free carboxylate group was maintained in the pore surface by adjusting the acidic reaction conditions. The highly stable Mg-MOF exhibits excellent performance for lead(II) sensing and removal from aqueous solutions. [ABSTRACT FROM AUTHOR]

Here we describe the synthesis of a compositional series of metal–organic framework crystalline-inorganic glass composites (MOF-CIGCs) containing ZIF-8 and an inorganic phosphate glass, 20Na2O–10NaCl–70P2O5, to expand the library of host matrices for metal–organic frameworks. By careful selection of the inorganic glass component, a relatively high loading of ZIF-8 (70 wt%) was achieved, which is the active component of the composite. A Zn⋯O–P interfacial bond, previously identified in similar composites/hybrid blends, was suggested by analysis of the total scattering pair distribution function data. Additionally, CO2 and N2 sorption and variable-temperature PXRD experiments were performed to assess the composites' properties. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) have become highly promising materials for a wide range of applications because of their distinct characteristics and structural adaptability. The utilization of MOFs in composite materials has the potential to expand their range of applications. This study focuses on the development of an iron-doped zinc metal organic framework (Fe@Zn-MOF-2) using a previously synthesized zinc-based MOF. The efficacy of Fe@Zn-MOF-2 was investigated for sensing Gd3+ and acetophenone, as well as its potential as an electrode material for energy storage devices. The photoluminescence sensing experiments showed a significant improvement in the efficiency of sensing Gd3+ and acetophenone when using the Fe@Zn-MOF-2 composite. The composite achieved sensing efficiencies of 97.73% and 98.45%, respectively, which were higher than the efficiencies of 33.25% and 35.71% observed when using only the Zn-MOF. Furthermore, both materials exhibited substantial disparities in specific capacitance when examined as energy storage electrodes through the methods of cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) analysis, and electrochemical impedance spectroscopy (EIS). Fe@Zn-MOF-2 exhibits a specific capacitance of 318.09 F g−1, while the Zn-MOF has a specific capacitance of 33.00 F g−1. Fe@Zn-MOF-2 exhibits a specific capacitance retention of 94.57% after undergoing 2000 cycles in cyclic voltammetry. The results emphasize the capability of Fe@Zn-MOF-2 for versatile uses in sensing and energy storage. [ABSTRACT FROM AUTHOR]

In this study, a novel screening approach is presented, merging capillary electrophoresis analysis with an enzymatic assay employing immobilized α-glucosidase. A metal–organic framework composite membrane was devised for α-glucosidase immobilization. Employing polyvinylidene fluoride (PVDF) as the substrate material, it was functionalized with dopamine, creating a polydopamine composite layer. This layer acted as a covalent linker, anchoring Zn2+, which subsequently chelated with the organic ligand 2-ethylimidazole, leading to the self-assembly of a three-dimensional porous framework ZIF-8. This structure facilitated the in situ encapsulation of α-glucosidase. Characterization techniques including scanning electron microscopy, Fourier transform infrared-attenuated total reflectance spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction validated the composite material's structure. A thorough investigation of various parameters affecting immobilization was conducted. The immobilized α-glucosidase exhibited enhanced pH tolerance, thermal stability, and remarkable reusability, retaining 79.3% of its original activity over 10 cycles, with a batch-to-batch reproducibility of 5.9% (n = 5). Its Michaelis–Menten constant (Km) was determined to be 2.85 mM. Application of this immobilized enzyme in screening potential inhibitors from 13 traditional Chinese medicines revealed Sanguisorba radix as the most potent inhibitor. This study underscores the potential of this immobilized enzyme screening strategy for identifying enzyme inhibitors in traditional Chinese medicines. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have potential as drug carriers on the basis of their surface areas and pore volumes that allow for high drug loading and fast release. The present study investigated solvothermal synthesis and comprehensive characterization (BET, FTIR, PXRD and SEM) of two closely related series of microporous copper MOFs, Cu-MOF(s) (s = single linker) based on BPDC (biphenyl-4,4-dicarboxylate) linker and Cu-MOF(m) (m = mixed linker) comprising both BPDC and BPY (4,4-bipyridine) as linkers, for easy encapsulation and sustained delivery of two drugs, ibuprofen and montelukast sodium. Finally, one-way analysis of variance was applied for comparative evaluation between various concentration ratios (MOF : drug) to conclude statistically significant difference of encapsulation power and sustained release trend between the two Cu-MOFs using a UV-visible spectrophotometer by obtaining the absorbance value at λmax for each drug. Due to porous crystalline properties of our synthetized Cu-MOFs, we ensured excellent encapsulation and sustainability of both drugs to conceive a novel sustained release system for ibuprofen and montelukast sodium, which is more effective in comparison with conventional dosages of 2 to 3 times a day. [ABSTRACT FROM AUTHOR]

Metal‐organic frameworks (MOFs) that exhibit dynamic phase‐transition behavior under external stimuli could have great potential in adsorptive separations. Here we report on a zinc‐based microporous MOF (JNU‐80) and its reversible transformation between two crystalline phases: large pore (JNU‐80‐LP) and narrow pore (JNU‐80‐NP). Specifically, JNU‐80‐LP can undergo a dehydration‐induced cluster consolidation under heat treatment, resulting in JNU‐80‐NP with a reduced channel that allows exclusion of di‐branched hexane isomers while high adsorption of linear and mono‐branched hexane isomers. We further demonstrate the fabrication of MOF‐polymer composite (JNU‐80‐NP‐block) and its application in the purification of di‐branched isomers from liquid‐phase hexane mixtures (98 % di‐branched) at room temperature, affording the di‐branched hexane isomers with 99.5 % purity and close to 90 % recovery rate over ten cycles. This work illustrates an interesting dehydration‐induced cluster consolidation in MOF structure and the ensuing channel shrinkage for sieving di‐branched hexane isomers, which may have important implications for the development of MOFs with dynamic behavior and their potential applications in non‐thermal driven separation technologies. [ABSTRACT FROM AUTHOR]

Photogenerated radicals are an indispensable member of the state‐of‐the‐art photochromic material family, as they can effectively modulate the photoluminescence and photothermal conversion performance of radical‐induced photochromic complexes. Herein, two novel radical‐induced photochromic metal–organic frameworks (MOFs), [Ag(TEPE)](AC) ⋅ 7/4H2O ⋅ 5/4EtOH (1) and [Ag(TEPE)](NC) ⋅ 3H2O ⋅ EtOH (2), are reported. Distinctly different topological networks can be obtained by judiciously introducing alternative π‐conjugated anionic guests, including a new topological structure (named as sfm) first reported in this work, describing as 4,4,4,4‐c net. EPR data and UV–Vis spectra prove the radical‐induced photochromic mechanism. Dynamic photochromism exhibits tunability in a wide CIE color space, with a linear segment from yellow to red for 1, while a curved coordinate line for 2, resulting in colorful emission from blue to orange. Moreover, photogenerated TEPE* radicals effectively activate the near‐infrared (NIR) photothermal conversion effect of MOFs. Under 1 W cm−2 808 nm laser irradiation, the surface temperatures of photoproducts 1* and 2* can reach ~160 °C and ~120 °C, respectively, with competitive NIR photothermal conversion efficiencies η=51.8 % (1*) and 36.2 % (2*). This work develops a feasible electrostatic compensation strategy to accurately introduce photoactive anionic guests into MOFs to construct multifunctional radical‐induced photothermal conversion materials with tunable photoluminescence behavior. [ABSTRACT FROM AUTHOR]

Achieving active site engineering at the atomic level poses a significant challenge in the design and optimization of catalysts for energy‐efficient catalytic processes, especially for a reaction with two reactants competitively absorbed on catalytic active sites. Herein, we show an example that tailoring the local environment of cobalt sites in a robust metal–organic framework through substituting the bridging atom from −Cl to −OH group leads to a highly active catalyst for oxygen activation in an oxidation reaction. Comprehensive characterizations reveal that this variation imparts drastic changes on the electronic structure of metal centers, the competitive reactant adsorption behavior, and the intermediate formation. As a result, exceptional low‐temperature CO oxidation performance was achieved with T25(Temperature for 25 % conversion)=35 °C and T100 (Temperature for 100 % conversion)=150 °C, which stands out from existing MOF‐based catalysts and even rivals many noble metal catalysts. This work provides a guidance for the rational design of catalysts for efficient oxygen activation for an oxidation reaction. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have been increasingly popular in photocatalytic water-splitting research areas due to their unique, tunable porosity, high stability, large surface activity, and manipulative topology. However, the incapability of MOFs in harvesting broad-solar irradiation and rapid electron-hole pairs recombination has limited their efficiency in practical applications, and their structures allow researchers to manipulate them toward better efficiency. Also, linker modification is achieved by reclaiming the organic linker, which constructs MOFs by functionalizing, changing the ligand's length, and using an aided organic linker. In addition, being a free space in their structure gives this opportunity to modify them easily with other compounds such as inorganic complex compounds and nanoparticles by incorporation, impregnation, and ship-in-a-bottle methods. The objectives of this review article are three-fold. First, to emphasize understanding of the fundamental correlation among promising strategies to improve the optoelectronic properties of MOFs such as light-harvesting capability and photoinduced electron-hole pairs for photocatalytic reactions involving water splitting reaction under broad solar irradiation. Second, to systematically summarize the organic linker modification and incorporation of polyoxometalate, coordination metal complexes, and various nanoparticles. Third, to discuss challenges and future research directions for the development of broad solar band activation of MOFs for photocatalysis purposes. Investigation of the different methods for modification of MOFs Review of the incorporation of complex compounds into MOFs in detail Investigation of all the strategies for incorporation of complex compounds into MOFs [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is deemed to be an environmentally friendly methodology for hydrogen and oxygen in various electrochemical systems. The electrocatalyst has a strong relationship with the performance of the oxygen evolution reaction (OER). Herein, Co3O4 nanopolyhedrons (Co3O4 NPs) and Co3O4 nanopolyhedrons with N-doped carbon (Co3O4 NPs-NC) were obtained by changing the pyrolysis temperature using ZIF-67 as the precursor template. Due to the poor conductivity of cobalt-based oxides, the introduction of carbon nanotubes (CNTs) significantly increased the electron transfer rate of the Co3O4 polyhedron, the Co3O4 NPs-NC/CNTs exhibited outstanding activity as a catalyst in OER. The reason for the favorable catalytic capability of this catalyst is that the Co3O4 NPs-NC with dodecahedral structure can supply abundant active sites, and its plentiful mesoporous structure can facilitate the adsorption of reactants and desorption of products. Therefore, the Co3O4 NPs-NC/CNTs composite with excellent electrochemical activity has broad application prospects as a promising catalyst. The excellent OER performance of Co3O4 NPs-NC/CNTs is attributed to having a polyhedral structure that replicates the ZIF-67 morphology and its rich mesoporous structure, which can provide more effective active sites. [ABSTRACT FROM AUTHOR]

Cu/ZnO/CeO2 nanocomposite was supported on metal organic framework (MOF-5) to enhance active sites dispersion and control the nanoparticles agglomeration during synthesis through strong metal-support interactions. The incorporation of MOF-5 alleviated the obstacle facing the commercial ternary Cu/ZnO/Al2O3 regarding low surface area due to nanoparticles agglomeration. In addition, Cu/ZnO/CeO2@MOF-5 gave higher methanol selectivity than the commercial catalyst which can be accounted for by the interfacial sites generated between MOF-5 and Cu/ZnO which favour methanol synthesis over carbon monoxide through regulating the intermediates bonding energies. CeO2 as support for Cu/ZnO nanoparticles was also compared with commercial support and showed to have led to smaller particle size and superior dispersion of Cu active sites as well. Cu/ZnO/CeO2@MOF-5 resulted in methanol STY of 23.3 mg gcat h−1 and selectivity of 79% at mild reaction temperature (260 °C) and pressure (10 bar). Two different MOFs including cerium based MOF and ZIF-8 demonstrated inferior performance compared to MOF-5. [ABSTRACT FROM AUTHOR]

To address global water pollution and crisis issue, wastewater recycling, seawater and brackish water desalination have been increasingly utilized to produce clean water. Ceramic membranes have been gaining widespread interest due to their unique physicochemical properties and high stability. Integrating nanoporous MOF (metal organic framework) with ceramic membranes could enable a rational design of ceramic-based MOF membranes with enhance sieving performance. Herein, we report an in-situ method to construct an inter-crystalline defect-free MOF layer on ZrO 2 ceramic membranes for efficient desalination application. After optimizing synthesis parameters, an inter-crystalline defect-free and well-intergrown ceramic-based MOF membrane was obtained. The ceramic-based MOF membranes not only demonstrated a near-complete salt rejection, but also exhibited high water flux, which are superior to most of the reported zeolite and MOF membranes. In addition, the MOF membranes exhibited promising performance and structure stability even when exposed to harsh water environments. Our work introduces a protocol for the design of high-performance ceramic-based MOF membrane as a promising candidate for challenging desalination applications under different environments. [Display omitted] • Regulation of synthesis parameters could improve the quality of MOF membranes. • Growth of MOF layer could enhance rejection performance of zirconia ceramic membrane. • Robust membrane structure and desalination performance were realized under harsh conditions. • Efficient separation and performance regeneration were achieved for real industrial wastewater. [ABSTRACT FROM AUTHOR]

Highly dispersed isolated sites offer opportunities to rationally design sensing materials with desired performance, but their stability under harsh reaction conditions is still challenging. Herein, we deposited the highly dispersed atomic layer deposition (ALD) platinum (Pt) species into optimized porous SnO 2 nanorods derived from the Sn-based metal organic frameworks (MOFs). With confining isolated Pt into porous SnO 2 , the optimum operating temperature of the sensor based on SnO 2 –Pt2 nanorods was decreased from 275 °C to 190 °C. And the response (R a /R g) to 5 ppm acetone was improved from 2.63 to 6.33, along with the decrease of response time from 23 s to 9 s. Combined with X-ray adsorption, near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and density functional theory (DFT) simulation, the highly dispersed Pt confined within SnO 2 nanorods are confirmed to heighten the adsorption of acetone at working temperature and lower the reaction activation energy. The confined structure enriches the acetone in hole, further enhancing its adsorption on Pt. The highly dispersed isolated Pt sites and confined effects dramatically promote the sensing performance. The understanding of structure-activity relationships offers a novel strategy to design the ultrasensitive and stable acetone sensing materials, and it shows potential applications in design of other gas sensing or catalytic materials. Highly dispersed isolated Pt species were deposited into optimized porous SnO 2 nanorods via atomic layer deposition for enhancing the stability under harsh working conditions. SnO 2 with Pt isolated sites inside of pores exhibits a low optimal working temperature at 190 °C and an extremely low detection limit of 19 ppb combined with a response of 6.33 to 5 ppm acetone and rapid response and recovery rates. Mechanistic investigations via in-situ characterization (NAP-XPS etc.) and theory calculation have confirmed that the excellent sensing performance are attributed to the heightened adsorption from the nanoconfined structure combined with decrease of reaction activation energy resulting from the isolated Pt sites. [Display omitted] [ABSTRACT FROM AUTHOR]

Nowadays, the problem of antibiotic pollution in the water environment is becoming more and more serious, which has caused great harm to human health and the circulatory system. Therefore, it is extremely crucial to design an effective and sensitive method for the recognition of antibiotics in water. In this research, 1‐(4‐carboxyphenyl)‐1H‐pyrazole‐3‐carboxylic acid (H2L) was used as a ligand to prepare a luminescent two‐dimensional (2D) metal–organic framework (MOF), CdL·H2O (1). 1 can specifically recognize antibiotic cephalothin (CET) in aqueous environments through a fluorescence‐enhanced response, which demonstrated a favorable linear correlation between the fluorescence intensities of 1 and the concentrations of CET (0–50 μM) with a linear fluorescence enhancement slope KEC value of 5.4750 × 104 M−1 and a limit of detection (LOD) of 165 nM. The fast response, good selectivity, anti‐interference ability, and reusability for CET recognition were also verified. 1 represents the inaugural MOF‐based fluorescent material designed for the recognition of CET. Additionally, the detection mechanism for CET was explored in detail with a view to better understanding the fluorescence sensing process. [ABSTRACT FROM AUTHOR]

Three distinct morphologies of Bi‐MOFs were innovatively employed as carriers, facilitating the formation of heterojunctions with BiPO4. Among these, the optimal photocatalytic performance was demonstrated by the type II heterojunction BiPO4/CAU‐17. Bi3+ competitively coordinated to crucially aid CAU‐17's transformation into a heterojunction, enhancing interfacial contact in BiPO4/CAU‐17. These photocatalysts effectively degraded dyes (RhB, MO, MB) and tetracycline (TC) under light exposure. RhB degradation was 3.33 times faster with BiPO4/CAU‐17 than BiPO4, 1.45 times faster than FCAU‐17, 1.36 times faster than FRCAU‐17, and 1.32 times faster than CAU‐17. Analyzing carrier density, Fermi level, and band structure through VB‐XPS, UV–VIS, and Mott–Schottky provided insights into enhanced separation of photoexcited electron–hole pairs. This study presents a novel approach to tackle the aggregation challenge of the wide‐bandgap material BiPO4 by using suitable MOFs as carriers. It offers valuable perspectives for the design and application of photocatalysts in environmental remediation. [ABSTRACT FROM AUTHOR]