Unlocking epoxy thermal management capability via hierarchical Ce-MOF@MoS2 hybrid constructed by in-situ growth method.

This study demonstrates the preparation of needle-like Ce-MOF crystals on molybdenum disulfide (MoS2) nanosheets using in-situ growth technology. This hybrid structure significantly enhances the thermal management and mechanical properties of thermosetting epoxy resin (EP). Specifically, EP/Ce-MOF@MoS2-3 exhibits a notable increase in tensile strength (TS) to 50.87 MPa and elongation at break (EB) to 10.84 %. Moreover, Ce-MOF@MoS2 provides synergistic flame retardant benefits, reducing the peak heat release rate (pHRR) and total heat release (THR) of EP/Ce-MOF@MoS2-3 by 38 % and 12.64 %, respectively, compared to EP-0. Additionally, Ce-MOF@MoS2 suppresses smoke and reduces toxic emissions; at a 3 % loading, it decreases CO and CO2 production in EP nanocomposites by 48.8 % and 38.7 %, respectively. Thus, this Ce-MOF@MoS2 hybrid, synthesized via in-situ growth, offers a novel approach for developing EP nanocomposites with superior thermal management and mechanical properties, along with effective flame retardancy and reduced hazardous emissions during thermal events.

In Situ Built ZnS/MXene Heterostructure by a Mild Method for Inhibiting Polysulfide Shuttle in Li-S Batteries.

With high specific surface area, excellent polysulfide conversion activity, and fast electron/ion transfer at the interface, MXene-derived heterostructures can be employed as catalysts for lithium-sulfur (Li-S) batteries to accelerate sulfur redox kinetics and suppress shuttle effect. However, the preparation of MXene-derived heterostructures often requires high-temperature reactions, which can easily lead to the oxidation of MXene and sacrifice the electrical conductivity. Herein, a catalytic two-dimensional heterostructure (ZnS/MXene) was successfully synthesized via a mild method. The MXene skeleton retains the original nanosheet structure without oxidation. The in situ-grown ZnS nanospheres prevent the restacking of MXene nanosheets, which not only increases the active sites, but also guarantees channels for the fast passage of lithium ions. The interfacial built-in electric field further promotes electron/ion migration, thereby expediting the polysulfide conversion and suppressing the shuttle effect. Consequently, the batteries using ZnS/MXene modified separators exhibit a high initial discharge capacity of 1230 mAh g-1 at 0.1 C and a low decaying rate of 0.082% per cycle after 500 cycles at 0.5 C. This work offers a reference for the fabrication of MXene-based heterostructure in Li-S batteries.

Chiral-induced covalent organic framework as novel chiral stationary phase for chiral separation using open-tubular capillary electrochromatography.

As a novel class of chiral stationary phase (CPS) material, chiral covalent organic frameworks (CCOFs) have already shown great promise in open-tubular capillary electrochromatography (OT-CEC) for chiral separation. The synthesis methods of CCOFs used in OT-CEC mainly include bottom-up, post modification and chiral induction. The CCOFs synthesized by bottom-up and post modification strategies already have lots of applications in capillary electrochromatography, however, the chiral-induced synthesized via an asymmetric catalytic strategy has not yet been reported for using as the chiral stationary phase (CPS) in OT-CEC or even in chromatographic separation. Herein, the chiral-induced COF (Λ)-TpPa-1 was synthesized by asymmetric catalytic synthesis and coated on the inner surface of a capillary by an in-situ growth strategy as the CPS for chiral drug separation. The baseline separation of six enantiomers was achieved within 14 min, with a high-resolution (Rs) range from 1.85 to 6.75. Moreover, the resolution and migration time of the capillary keep stable within 160 runs, showing its superior stability and repeatability. This research provides a new idea for the development and application of novel CPS materials in the field of capillary electrochromatography separation, also shows the new application of chiral induced COFs. Furthermore, the chiral-induced CCOFs can be easily applied to other chromatographic separation fields, exhibiting its extensive application value in chiral analysis separation.

Optimization of Thermoelectric Properties and Physical Mechanisms of Cu2Se-Based Thin Films via Heat Treatment.

Cu2Se is an attractive thermoelectric material due to its layered structure, low cost, environmental compatibility, and non-toxicity. These traits make it a promising replacement for conventional thermoelectric materials in large-scale applications. This study focuses on preparing Cu2Se flexible thin films through in situ magnetron sputtering technology while carefully optimizing key preparation parameters, and explores the physical mechanism of thermoelectric property enhancement, especially the power factor. The films are deposited onto flexible polyimide substrates. Experimental findings demonstrate that films grown at a base temperature of 200 °C exhibit favorable performance. Furthermore, annealing heat treatment effectively regulates the Cu element content in the film samples, which reduces carrier concentration and enhances the Seebeck coefficient, ultimately improving the power factor of the materials. Compared to the unannealed samples, the sample annealed at 300 °C exhibited a significant increase in room temperature Seebeck coefficient, rising from 9.13 µVK-1 to 26.73 µVK-1. Concurrently, the power factor improved from 0.33 µWcm-1K-2 to 1.43 µWcm-1K-2.

Ambient Synthesis of Vanadium-based Prussian Blue Analogues Nanocubes for High-performance and Durable Aqueous Zinc-ion Batteries with Eutectic Electrolytes.

Prussian blue analogues (PBAs) have been widely studied in aqueous zinc-ion batteries (AZIBs) due to the characteristics of large specific surface area, open aperture, and straightforward synthesis. In this work, vanadium-based PBA nanocubes were firstly prepared using a mild in-situ conversion strategy at room temperature without the protection of noble gas. Benefiting from the multiple-redox active sites of V3+/V4+, V4+/V5+ and Fe2+/Fe3+, the cathode exhibited an excellent discharge specific capacity of 200 mA h g-1 in AZIBs, which is much higher than those of other metal-based PBAs nanocubes. To further improve the long-term cycling stability of the V-PBA cathode, a high concentration water-in-salt electrolyte (4.5 M ZnSO4 + 3 M Zn(OTf)2), and a water-based eutectic electrolyte (5.55 M glucose + 3 M Zn(OTf)2) were designed to successfully inhibit the dissolution of vanadium and improve the deposition of Zn2+ onto the zinc anode. More importantly, the assembled AZIBs maintained 55% of their highest discharge specific capacity even after 10000 cycles at 10 A g-1 with superior rate capability. This study provides a new strategy for the preparation of pure PBA nanostructures and a new direction for enhancing the long-term cycling stability of PBA-based AZIBs at high current densities for industrialization prospects.

In-situ growth of a covalent organic framework-based matrix-compatible microextraction coating for sensitive extraction of multiple pesticides.

The potential pesticide hazard to non-target organisms is a global concern. It is critical to develop the sensitive detection methods of multiple pesticides in various complex matrices. Here, benzene-1,3,5-tricarbaldehyde (BTCA) and 1,3,5-Tri (4-aminophenyl) benzene (TAPB) were employed as precursors for the in-situ growth of COFTAPB-BTCA on the surface of amino-functionalized stainless steel wire (SS) via a solvothermal method. The successful COFTAPB-BTCA bonded fiber exhibited significant enrichment capability of pyrethroids insecticides (PYs), organophosphorus (OPPs), and organochlorine (OCPs), with enrichment factors (EFs) ranging from 1133-7762, 1319-7291, and 734.1-2882, respectively. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations indicated that various interactions contributed to its high enrichment capacity. Automated detection of PYs, OPPs, and OCPs in water, foods, and biological samples was realized by coupling this fiber with gas chromatography-mass spectrometry (GC-MS). The detection limits were as low as 0.0370-0.657 ng/L, 0.0128-0.400 ng/L, and 0.0329-0.202 ng/L for PYs, OPPs, and OCPs, respectively. In addition, the environmental risks of these samples were assessed based on the above data. This work not only provided a straightforward technique for sensitive monitoring of pesticides in complex matrices but also presented a novel approach for the in-situ controlled growth of versatile adsorbents with broad-spectrum properties.

Impregnate Carbonation: CO2-Guided In Situ Growth of Robust Superhydrophobic Structures on Concrete Surfaces.

Superhydrophobic surfaces applying on concrete can greatly improve the durability of concrete by preventing the damage from water. However, traditional design of superhydrophobic concrete surfaces by external coating encounters to problems of flaking and poor surface robustness, while that by adding hydrophobic agents or particles faces the challenges of strength damage of concrete. Drawing inspiration from the carbonation phenomenon of concrete, here a new design of in situ growing superhydrophobic structures on concrete is proposed: The concrete sample is impregnated into Mg2+-containing silane-water system with continuous CO2 injection. The contact angle of the concrete surface achieves 171.9° without obvious strength decrease after 120 min, which are mainly attributed to the formation of CaxMg1-xCO3 crystals with micro-nano-structures and the reduction of carbonates surface energy by silane. This superhydrophobic concrete structure can be divided into a superhydrophobic-hydrophobic-hydrophilic three layers structure, providing the stable water-proof protection under mechanical fatigue, capillary water absorption, UV aging, sulfate attack, and impurity water impact tests due to the in situ growing robust superhydrophobic structures. Furthermore, it captures 29.80 g m-2 CO2 during the reaction process, providing new insights for the design and preparation of eco-friendly superhydrophobic concrete.

In Situ Synthesis of Hierarchical Co(CO3)0.5(OH)·0.11H2O@ZIF-67/WO3 With High Humidity Immunity and Response to H2S Sensing.

H2S gas sensors with facile preparation, low detection limits, and high selectivity are crucial for environmental and human health monitoring. However, it is difficult to maintain a high response of H2S gas sensors under high humidity in practical applications. To face this dilemma, a layer-by-layer growth method is applied to in situ prepare a nanostructured Co(CO3)0.5(OH)·0.11H2O/WO3 coated by a hydrophobic hierarchical ZIF-67 as the H2S sensor. This novel composite exhibits excellent humidity immunity without sacrificing the excellent sensitivity and selectivity of H2S. At a low operating temperature of 90 °C, a remarkable response value of 1052.3 to 100 ppm H2S has been achieved, which is 779 and 9.36 times higher than that of pure WO3 and Co(CO3)0.5(OH)·0.11H2O/WO3, respectively. More importantly, an 82.2% relative response value remains at a high humidity of 75%RH. The sensing mechanisms are investigated using gas chromatography-mass spectrometry (GC-MS), which revealed that the reaction products are H2O and SO2. The high humidity immunity and fast response of the Co(CO3)0.5(OH)·0.11H2O@ZIF-67/WO3 demonstrate the layer-by-layer in situ synthesis method holds the potential application for the development of high-performance WO3-based H2S sensors.

Self-supporting and hierarchical porous membrane of bacterial nanocellulose@metal-organic framework for ultra-high adsorption of Congo red.

The widespread use of synthetic dyes has serious implications for both the environment and human health. Therefore, there is an urgent need for the development of novel, high-efficiency adsorbents for these dyes. In this study, a Zirconium-based metal-organic framework (MOF) with controllable morphology was in-situ grown on bacterial nanocellulose (BC) via a solvothermal method. The resulting BC@MOF composite nanofibers have a high specific surface area of 651 m2/g and can be assembled into a self-supported porous membrane (BMMCa) through vacuum filtration with the assistance of calcium ions. The addition of Ca(II) significantly enhanced the mechanical properties of the membrane through dispersion effect and electrostatic interactions, as well as enhancing its adsorption performance through the salting-out effect. The BMMCa membrane, with its hierarchical porous structure and high flux, exhibits high selectivity for Congo red (CR) with an ultra-high adsorption capacity of 3518.6 mg/g. Furthermore, the self-supporting membrane achieved rapid and convenient removal of CR through circulating filtration adsorption. The adsorption mechanism and selectivity were verified through the molecular dynamics simulation calculations by Materials Studio (MS) software. This membrane-based adsorbent, with its ultra-high adsorption capacity, good selectivity, and recycling ability, has great potential for practical wastewater treatment applications.

Tough Self-Healing Materials via In Situ Growth of Zeolitic Imidazolate Framework-8 Nanocrystals in Polymers.

Construction of self-healing materials with improved mechanical performance is a great challenge. A strong and tough self-healing composite is fabricated via in situ growth of zeolitic imidazole framework-8 (ZIF-8) nanocrystals in imidazole-containing polymer networks. By adjusting the stoichiometric ratio of the zinc salt to 2-methylimidazole, composites with various mechanical performances are obtained. The existence of ZIF-8 nanocrystals via in situ growth in the polymer networks is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The zinc-imidazole interactions between the ZIF-8 nanocrystals and the polymer are confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. The composites can repair themselves under mild conditions owing to dynamic zinc-imidazole interactions. The self-healing efficiency of composites can reach up to 91% under the condition of 60 °C for 48 h. In contrast to the pure zinc cation crosslinking system, the composite containing ZIF-8 nanocrystals prepared via in situ growth exhibited enhanced tensile strength and toughness by 43% and 100%, respectively. This study proves that incorporating the metal-organic frameworks (MOFs) materials into a self-healing system via an in situ growth strategy is highly promising for designing self-healing materials with improved mechanical performance.