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Crystalline polymer materials, e.g., hyper-crosslinked polystyrene, conjugate microporous polymers and covalent organic frameworks, are used as catalyst carriers, organic electronic devices and molecular sieves. Their properties and applications are highly dependent on their crystallinity. An efficient polymerization strategy for the rapid preparation of highly or single-crystalline materials is beneficial not only to structure-property studies but also to practical applications. However, polymerization usually leads to the formation of amorphous or poorly crystalline products with small grain sizes. It has been a challenging task to efficiently and precisely assemble organic molecules into a single crystal through polymerization. To address this issue, we developed a supercritically solvothermal method that uses supercritical carbon dioxide (sc-CO 2 ) as the reaction medium for polymerization. Sc-CO 2 accelerates crystal growth due to its high diffusivity and low viscosity compared with traditional organic solvents. Six covalent organic frameworks with different topologies, linkages and crystal structures are synthesized by this method. The as-synthesized products feature polarized photoluminescence and second-harmonic generation, indicating their high-quality single-crystal nature. This method holds advantages such as rapid growth rate, high productivity, easy accessibility, industrial compatibility and environmental friendliness. In this protocol, we provide a step-by-step procedure including preparation of monomer dispersion, polymerization in sc-CO 2 , purification and characterization of the single crystals. By following this protocol, it takes 1-5 min to grow sub-mm-sized single crystals by polymerization. The procedure takes ~4 h from preparation of monomer dispersion and polymerization in sc-CO 2 to purification and drying of the product., (© 2023. Springer Nature Limited.)

Conductive metal-organic frameworks (MOFs) have performed well in the fields of energy and catalysis, among which two-dimensional (2D) and three-dimensional (3D) MOFs are well-known. Here, we have synthesized a one-dimensional (1D) conductive metal-organic framework (MOF) in which hexacoordinated 1,5-Diamino-4,8-dihydroxy-9,10-anthraceneedione (DDA) ligands are connected by double Cu ions, resulting in nanoribbon layers with 1D π-d conjugated nanoribbon plane and out-of-plane π-π stacking, which facilitates charge transport along two dimensions. The DDA-Cu as a highly conductive n-type MOF has high crystalline quality with a conductivity of ~ 9.4 S·m -1 , which is at least two orders of magnitude higher than that of conventional 1D MOFs. Its electrical band gap (E g ) and exciton binding energy (E b ) are approximately 0.49 eV and 0.3 eV, respectively. When utilized as electrode material in a supercapacitor, the DDA-Cu exhibits good charge storage capacity and cycle stability. Meanwhile, as thse active semiconductor layer, it successfully simulates the artificial visual perception system with excellent bending resistance and air stability as a MOF-based flexible optoelectronic synaptic case. The controllable preparation of high-quality 1D DDA-Cu MOF may enable new architectural designs and various applications in the future., (© 2022. The Author(s).)

Cu-benzenehexathiol (Cu-BHT) has attracted significant attention due to its record high electrical conductivity and crystal defects Cu 2c . However, the nonporous structure and small specific surface area of Cu-BHT with two-dimensional kagome lattice invariably limit its practical application in sensing and catalysis. In this work, Cu-BHT nanotubes (Cu-BHT-NTs) are designed and prepared via a facile homogeneous reaction to solve these problems. Compared with the traditional nanorod-like structure, the Cu-BHT-NTs not only have a higher specific surface area but also possess a higher proportion of crystal defects (66.6%). The successfully configured DPPTT/Cu-BHT-NTs heterostructure organic field-effect transistor (OFET)-based sensor exhibits excellent sensitivity as high as 13 610%, a minimum detection limits down to 5 ppb, and exceptional selectivity to nitric oxide (NO) toxic gases. Theoretical analysis systematically shows that Cu 2c sites in the Cu-BHT-NTs increase the number of electrons transferred from the heterostructure to NO molecules, confirming that the high sensitivity and selectivity result from the high binding between Cu-BHT-NTs and NO molecules. Furthermore, a fully flexible device based on the heterojunction OFET sensor is prepared to ensure the convenience of wearing and carrying gas sensors, opening up a new avenue for the next generation of wearable intelligent electronics., (© 2022 Wiley-VCH GmbH.)

2D metal-organic framework (MOF) film as the active layer show promising application prospects in various fields including sensors, catalysis, and electronic devices. However, exploring the application of 2D MOF film in the field of artificial synapses has not been implemented yet. In this work, we fabricated a novel 2D MOF film (Cu-THPP, THPP=5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine), and further used it as an active layer to explore the application in the simulation of human brain synapses. It shows excellent light-stimulated synaptic plasticity properties, and exhibits the foundation function of synapses such as long-term plasticity (LTP), short-term plasticity (STP), and the conversion of STP to LTP. Most critically, the MOF based artificial synaptic device exhibits an excellent stability in atmosphere. This work opens the door for the application of 2D MOF film in the simulation of human brain synapses., (© 2021 Wiley-VCH GmbH.)

Recently, conductive metal–organic frameworks (c‐MOFs) have drawn tremendous attention for the application in oxygen evolution reaction (OER) due to their superior conductivity and highly accessible active sites. Herein, a facile method is reported to prepare a series of bimetallic c‐MOFs (NixFe1‐x‐THQ, THQ = tetrahydroxy‐1,4‐benzoquinone hydrate) by using the smallest benzene‐based ligand with high‐density catalytic active sites for OER. By adjusting the ratio of Ni/Fe, a series of catalysts with optimal electronic structures and adsorption capacity to intermediates, and faster charge transport are obtained. Among them, Ni0.5Fe0.5‐THQ exhibits superior catalytic performances for OER with a low overpotential of 272 mV at 10 mA cm−2, a small Tafel slope of 47.9 mV, and robust operation for 40 h with no detectable activity decay, which is far superior to commercial RuO2, most of traditional MOFs and even some monometallic conductive MOFs. Moreover, both the measured and simulated results manifest that Ni0.5Fe0.5‐THQ can tailor the d‐band center, and induce the directional transfer of electrons, optimizing the rate‐determining step and adsorption capacity to intermediates during OER, thus exhibits superior electrochemical activity. This work not only presents a strategy to fabricate an electrocatalyst with remarkable OER performance but also promotes the development of THQ‐based c‐MOFs for electrocatalysis. [ABSTRACT FROM AUTHOR]

Cu‐benzenehexathiol (Cu‐BHT) has attracted significant attention due to its record high electrical conductivity and crystal defects Cu2c. However, the nonporous structure and small specific surface area of Cu‐BHT with two‐dimensional kagome lattice invariably limit its practical application in sensing and catalysis. In this work, Cu‐BHT nanotubes (Cu‐BHT‐NTs) are designed and prepared via a facile homogeneous reaction to solve these problems. Compared with the traditional nanorod‐like structure, the Cu‐BHT‐NTs not only have a higher specific surface area but also possess a higher proportion of crystal defects (66.6%). The successfully configured DPPTT/Cu‐BHT‐NTs heterostructure organic field‐effect transistor (OFET)‐based sensor exhibits excellent sensitivity as high as 13 610%, a minimum detection limits down to 5 ppb, and exceptional selectivity to nitric oxide (NO) toxic gases. Theoretical analysis systematically shows that Cu2c sites in the Cu‐BHT‐NTs increase the number of electrons transferred from the heterostructure to NO molecules, confirming that the high sensitivity and selectivity result from the high binding between Cu‐BHT‐NTs and NO molecules. Furthermore, a fully flexible device based on the heterojunction OFET sensor is prepared to ensure the convenience of wearing and carrying gas sensors, opening up a new avenue for the next generation of wearable intelligent electronics. [ABSTRACT FROM AUTHOR]

Electrically conductive metal–organic frameworks (EC‐MOFs) are suitable for electrochemical sensing because of their unique structure and properties. Herein, an on‐chip electrochemical micro‐biosensor is designed to study the electrocatalytic interfaces, which are generally buried between the solid support and liquid electrolyte in conventional electrochemical sensing methods. The gas–liquid interfacial reaction method is used to obtain a Cu‐benzenehexathiol (Cu‐BHT) thin film with a flat up‐side surface and synaptic‐like structure on the bottom‐side surface. The effect of surface morphology on the film sensing performance is studied using the prepared Cu‐BHT film‐based on‐chip micro‐biosensor. The bottom‐side surface exhibited significantly higher H2O2 sensing performance than that of the smooth up‐side surface. The synaptic‐like structure has dense crystal defects (ts‐Cu), which act as nanozymes and play an important role in improving the H2O2 sensing performance. This study clarifies the role of crystal defects in Cu‐BHT sensing using the micro‐biosensor and allows the in‐situ study of electrochemical interface of EC‐MOF films during biosensing. [ABSTRACT FROM AUTHOR]

2D metal‐organic framework (MOF) film as the active layer show promising application prospects in various fields including sensors, catalysis, and electronic devices. However, exploring the application of 2D MOF film in the field of artificial synapses has not been implemented yet. In this work, we fabricated a novel 2D MOF film (Cu‐THPP, THPP=5,10,15,20‐Tetrakis(4‐hydroxyphenyl)‐21H,23H‐porphine), and further used it as an active layer to explore the application in the simulation of human brain synapses. It shows excellent light‐stimulated synaptic plasticity properties, and exhibits the foundation function of synapses such as long‐term plasticity (LTP), short‐term plasticity (STP), and the conversion of STP to LTP. Most critically, the MOF based artificial synaptic device exhibits an excellent stability in atmosphere. This work opens the door for the application of 2D MOF film in the simulation of human brain synapses. [ABSTRACT FROM AUTHOR]

Owing to their excellent physical and electrical properties, metal–organic framework (MOF) materials with well‐defined supramolecular structures have received extensive research attention. However, the fabrication of large‐area two‐dimensional (2D) MOF films is still a significant challenge. Herein, we propose a novel electrochemical (EC) synthesis method for the preparation of large‐area Cu3(HHTP)2 MOF film on single‐crystal Cu (100) anode. The surface reaction was achieved via charge‐induced molecular assembly. The synthesized MOF film exhibited a high crystalline quality with an electrical conductivity of approximately 0.087 S cm−1, which was around 1000 times larger than the previously reported values for the same material prepared by the interface method. In addition, Cu2(MTCP), Cu3(BTPA)2, and Cu3(TPTC)2 MOF films were synthesized on Cu foil with the same strategy, which confirmed the universality of the proposed method. This controllable EC method can be effectively applied to the industrial‐scale production of 2D MOF films on Cu foil. [ABSTRACT FROM AUTHOR]

In this paper, a facile route is reported for the synthesis of MIL-53(Al) particles with different sizes and morphologies via the addition of various ratios of an esterified ligand to realize the deferred release of the ligand. Detailed proof indicates that the hydrolysis and deferred release of the ligand play a crucial role in modulating the morphology and size of the obtained MIL-53 nanoparticles without disrupting the original structure and framework of MIL-53. A possible mechanism for the growth of MIL-53 crystals with different exposed facets is proposed based on the structure of MIL-53 and BFDH (Bravais, Friedel, Donnay and Harker) theory. In addition, the influence of the crystal morphologies or exposed surfaces on the breathing effect and gas adsorption performance was evaluated using N2 and CO2 adsorption, and the as-prepared MIL-53 particles showed different adsorption isotherms and adsorption behavior under the same conditions. The MIL-53 particles synthesized using an appropriate amount of an esterified ligand could present an enhanced surface area when compared to that of bulk MIL-53, and the breathing effect during CO2 adsorption was moderate, while excessive amounts of the esterified ligand resulted in a decrease in the porosity and the formation of boehmite. Based on the experiment, the discrepancy in the breathing effect is mainly attributed to the stability of the narrow pore form with different exposed facets, but not the decreased particle size. [ABSTRACT FROM AUTHOR]

Over the past decades, extensive efforts have been devoted to modulating the textural properties, morphology and microstructure of γ-Al2O3, since the physiochemical properties of γ-Al2O3 have close correlations with the performance of hydrotreating catalysts. In this work, a spongy mesoporous γ-alumina (γ-Al2O3) was synthesized using Al-based metal-organic frameworks (Al-MOFs) as precursor by two-step pyrolysis, and this Al-MOF-derived γ-Al2O3 was used as hydrodesulfurization (HDS) catalyst support, to explore the effect of support on the HDS performance. Compared with industrial γ-Al2O3, the spongy alumina displayed well-developed porosity with relatively high surface area, large pore volume, and abundant weak Lewis acid sites. Based on catalyst characterization and performance evaluation, sulfurized molybdenum and cobalt molecules were able to incorporate and highly disperse into channels of the spongy mesoporous alumina, increasing the dispersion of active catalytic species. The spongy γ-Al2O3 was also able to enhance the diffusion efficiency and mass transfer of reactant molecules due to its improved texture properties. Therefore, the corresponding catalyst presented higher activities toward HDS of dibenzothiophene (DBT) than that from industrial alumina. The spongy mesoporous γ-alumina synthesized by Al-MOFs provides a new alternative to further develop novel γ-alumina materials with different texture and various nanoporous structures, considering the diversity of MOFs with different compositions, topological structures, and morphology. [ABSTRACT FROM AUTHOR]

Revealing the mechanism for effective furan ring-opening process on transitional metal catalyst is critical for realizing the production of 1,5-pentanediol (1,5-PeO) through furfural alcohol (FOL). Herein, a Co-CoO x metal-metal oxide catalyst derived from 2D Co-MOF was synthesized, exhibiting high selectivity for 1,5-PeO (46%) and suppressing the selectivity of 1,2-PeO to 3.74% at 170 °C, 3 MPa H 2 for 1.5 h. The coordination between Co2+ and ligand in MOF could form highly dispersed Co nanoparticles associated with CoO x containing oxygen vacancy, and the inherited flower-like 2D nanosheets exposed more accessible Co-CoO x active sites. Due to the proximity and synergistic effect between Co0 and oxygen vacancy in CoO x , the catalyst also realized the ring-opening of 2-methylfuran, and a mechanism based on dual O adsorption was proposed. This work demonstrates the decisive effect of oxygen vacancy during the formation of 1,5-PeO through FOL route, and deepen the understanding the mechanism of transition metal catalysts. [Display omitted] • Monometallic Co-based catalysts with Co-CoO x active sites were prepared from MOF. • The route to 1,2-PeO was suppressed (S 1,5-PeO : 46%, S 1,2-PeO : 3.7%) during reaction. • The dual O atoms adsorption of FOL on Coδ+ next to oxygen vacancy was investigated. • The synergistic mechanism of metallic Co and CoO x for hydrogenolysis was explored. [ABSTRACT FROM AUTHOR]

In this work, the block-shaped Al-based metal–organic frameworks (Al-MOFs) MIL-53 have been synthesized by hydrothermal method. To detect the correlation between the structure of Al-MOFs and the formation of alumina, the ligands are eliminated by thermal treatment. MIL-53 and the calcination products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption and solid-state 27 Al nuclear magnetic resonance ( 27 Al NMR). It was found that after calcination, the block-shaped Al-MOFs precursor turns into high-crystallinity mesoporous alumina nanosheets, and the thermal treatment product γ -alumina possesses a dual pore system and a large surface area (146 m 2 /g), with five-fold aluminum. During the thermal treatment process, the structure of MIL-53 and its secondary building units have structure-directed effect in the formation of alumina. [ABSTRACT FROM AUTHOR]

The anchoring of Weakley-type polyoxometalate (POM) Na 7 [H 2 LaW 10 O 36 ] in mesoporous metal-organic framework (MOF) MIL-101(Cr) to prepare a novel host-guest composite is here reported for the first time. The successful encapsulation of LaW 10 into MIL-101(Cr) has been achieved via facile tandem post-synthetic modification strategy and confirmed by several instrumental techniques. The LaW 10 guests were dispersed homogeneously in MIL-101(Cr) nanocages at molecular level. The as-synthesized composite combines both the merits of the POMs (remarkable efficiency and reversible redox) and MOF (sufficient recyclability and exceptional porosity), thus displaying obvious host-guest synergistic effect. The LaW 10 O 36 @MIL-101(Cr) composite served as heterogeneous single-site catalyst for ODS process and exhibited excellent catalytic performance, with removal efficiency of 99.1, 94.5 and 84.7% for DBT, 4,6-DMDBT and BT, respectively. Thanks to the confinement effect from Cr···O W coordinative interaction, the catalyst provided outstanding recyclability and stability, and can be reused for seven times without leaching, structural alteration and deactivation. Moreover, the structure-activity relationship was investigated in detail, as well as the proposed mechanism. Image 1 • The Weakley structure POMs were encapsulated into MIL-101(Cr) for the first time. • The LaW 10 O 36 were dispersed uniformly within MIL-101(Cr) at molecular level. • The host-guest synergistic effect enhanced remarkably ODS efficiency and durability. • The confinement effect of MIL-101(Cr) on LaW 10 O 36 results in excellent ODS recyclability. [ABSTRACT FROM AUTHOR]