Construction of Trisubstituted Hydrazones via Base-Mediated Cascade Condensation N-Alkylation.

A practical base-promoted tandem condensation N-alkylation reaction for the formation of trisubstituted hydrazones has been developed employing aldehydes and hydrazines with alkyl halides. Crucially, this reaction successfully overcomes chemoselectivity problems, allowing for the reaction of multiple components in a one-pot manner. Halo- and heterofunctional groups, as well as free hydroxyl and amino groups, are tolerated in this transformation to produce a wide range of trisubstituted hydrazones in good to excellent yields.

Evaluation of sustainable development capacity of water sources: a case study of China.

The issue of water scarcity has drawn attention from all over the world. The coordination of the interaction between ecological and environmental development of water sources and socio-economic development is currently an essential issue that needs to be solved in order to safeguard the water resources environment for human survival. In this essay, we suggest a paradigm for assessing the sustainable exploitation of water resources. First, three ecological, economic, and social factors are investigated. Twenty essential evaluation indexes are then constructed using the Delphi approach, along with an index system for assessing the potential of water sources for sustainable development. The weights of each evaluation index were then determined using the combination assignment approach, which was then suggested. The coupled degree evaluation model of the capability for sustainable development of water sources was then developed. In order to confirm the viability and validity of the suggested model, the model was used to assess the Liwu River water source's capacity for sustainable growth in the context of the South-North Water Transfer in Shandong, China. It is believed that the aforementioned study would serve as a helpful resource when evaluating the capacity of water sources for sustainable development.

Platform for the Immobilizing of Ultrasmall Pd Clusters for Carbonylation: In Situ Self-Templating Fabrication of ZIF-8 on ZnO.

Incorporating metal clusters into the confined cavities of metal-organic frameworks (MOFs) to form MOF-supported catalysts has attracted considerable research interest with regard to carbonylation reactions. Herein, a self-templating method is used to prepare the zinc oxide (ZnO)-supported core-shell catalyst ZnO@Pd/ZIF-8. This facile strategy controls the growth of metal sources on the ZIF-8 shell layer and avoids the metal diffusion or aggregation problems of the conventional synthesis method. The characteristics of the catalysts show that the palladium (Pd) clusters are highly dispersed with an average particle size of ≈1.2 nm, making them excellent candidates as a catalyst for carbonylation under mild conditions. The optimal catalyst (1.25-ZnO@Pd/ZIF-8) exhibits excellent activity in synthesizing α, ß-alkynyl ketones under 1 atm of carbon monooxide (CO), and the conversion rate of 1, 3-diphenylprop-2-yn-1-one is 3.09 and 3.87 times more than those of Pd/ZIF-8 and Pd2+ , respectively, for the first 2 h. Moreover, the 1.25-ZnO@Pd/ZIF-8 is recyclable, showing negligible metal leaching, and, under the conditions used in this investigation, can be reused at least five times without considerable loss in its catalytic efficiency. This protocol can also be applied with other nucleophile reagents to synthesize esters, amides, and acid products.

Nanocellulose-based composite aerogels toward the environmental protection: Preparation, modification and applications.

Nanocellulose aerogel has the advantages of porosity, low density and high specific surface area, which can effectively realize the adsorption and treatment of wastewater waste gas. The methods of preparing nanocellulose mainly include mechanical, chemical and biological methods. Nanocellulose is formed into nanocellulose aerogel after gelation, solvent replacement and drying processes. Based on the advantages of easy modification of nanocellulose aerogels, nanocellulose aerogels can be functionalized with conductive fillers, reinforcing fillers and other materials to give nanocellulose aerogels in electrical, mechanical and other properties. Through functionalization, the properties of nanocellulose composite aerogel such as hydrophobicity and adsorption are improved, and the aerogel is endowed with the ability of electrical conductivity and electromagnetic shielding. Through functionalization, the applicability and general applicability of nanocellulose composite aerogel in the field of environmental protection are improved. In this paper, the preparation and functional modification methods of nanocellulose aerogels are reviewed, and the application prospects of nanocellulose composite aerogels in common environmental protection fields such as dye adsorption, heavy metal ion adsorption, gas adsorption, electromagnetic shielding, and oil-water separation are specifically reviewed, and new solutions are proposed.

Hierarchically Porous Carbon Nanosheets from One-Step Carbonization of Zinc Gluconate for High-Performance Supercapacitors.

Supercapacitors, with high energy density, rapid charge-discharge capabilities, and long cycling ability, have gained favor among many researchers. However, the universality of high-performance carbon-based electrodes is often constrained by their complex fabrication methods. In this study, the common industrial materials, zinc gluconate and ammonium chloride, are uniformly mixed and subjected to a one-step carbonization strategy to prepare three-dimensional hierarchical porous carbon materials with high specific surface area and suitable nitrogen doping. The results show that a specific capacitance of 221 F g-1 is achieved at a current density of 1 A g-1. The assembled symmetrical supercapacitor achieves a high energy density of 17 Wh kg-1, and after 50,000 cycles at a current density of 50 A g-1, it retains 82% of its initial capacitance. Moreover, the operating voltage window of the symmetrical device can be easily expanded to 2.5 V when using Et4NBF4 as the electrolyte, resulting in a maximum energy density of up to 153 Wh kg-1, and retaining 85.03% of the initial specific capacitance after 10,000 cycles. This method, using common industrial materials as raw materials, provides ideas for the simple preparation of high-performance carbon materials and also provides a promising method for the large-scale production of highly porous carbons.

In Situ Fabrication of High Dielectric Constant Composite Films with Good Mechanical and Thermal Properties by Controlled Reduction.

As a common two-dimensional carbon material, graphene has been widely doped into polymers to prepare high-performance dielectric materials. However, the shortcomings of graphene, such as large specific surface area and poor dispersion, limit its further application. Therefore, in this work, to solve the problem regarding the uniform dispersion of graphene in the matrix, in situ polymerization was used to prepare graphene/polyimide films, in which 1,4-diiodobutane was used as a reduction agent to prevent the aggregation of graphene oxide (GO) during imidization. High dielectric constant composite films were obtained by adjusting the ratio of 1,4-diiodobutane in GO. The results show that the resulting graphene/polyimide composite film possessed a dielectric constant of up to 197.5, which was more than 58 times higher than that of the polyimide (PI) film. Furthermore, compared to the pure PI film, the composite films showed better thermal stability and mechanical properties. Thermal performance tests showed that the 1,4-diiodobutane added during the preparation of the composite film was thermally decomposed, and there was no residue. We believe our preparation method can be extended to other high dielectric composite films, which will facilitate their further development and application in high power density energy storage materials.

Performance of Rod-Shaped Ce Metal-Organic Frameworks for Defluoridation.

The performance of a Ce(III)-4,4',4″-((1,3,5-triazine-2,4,6-triyl) tris (azanediyl)) tribenzoic acid-organic framework (Ce-H3TATAB-MOFs) for capturing excess fluoride in aqueous solutions and its subsequent defluoridation was investigated in depth. The optimal sorption capacity was obtained with a metal/organic ligand molar ratio of 1:1. The morphological characteristics, crystalline shape, functional groups, and pore structure of the material were analyzed via SEM, XRD, FTIR, XPS, and N2 adsorption-desorption experiments, and the thermodynamics, kinetics, and adsorption mechanism were elucidated. The influence of pH and co-existing ions for defluoridation performance were also sought. The results show that Ce-H3TATAB-MOFs is a mesoporous material with good crystallinity, and that quasi-second kinetic and Langmuir models can describe the sorption kinetics and thermodynamics well, demonstrating that the entire sorption process is a monolayer-governed chemisorption. The Langmuir maximum sorption capacity was 129.7 mg g-1 at 318 K (pH = 4). The adsorption mechanism involves ligand exchange, electrostatic interaction, and surface complexation. The best removal effect was reached at pH 4, and a removal effectiveness of 76.57% was obtained under strongly alkaline conditions (pH 10), indicating that the adsorbent has a wide range of applications. Ionic interference experiments showed that the presence of PO43- and H2PO4- in water have an inhibitory effect on defluoridation, whereas SO42-, Cl-, CO32-, and NO3- are conducive to the adsorption of fluoride due to the ionic effect.

Recent Progress in Modifications, Properties, and Practical Applications of Glass Fiber.

As a new member of the silica-derivative family, modified glass fiber (MGF) has attracted extensive attention because of its excellent properties and potential applications. Surface modification of glass fiber (GF) greatly changes its performance, resulting in a series of changes to its surface structure, wettability, electrical properties, mechanical properties, and stability. This article summarizes the latest research progress in MGF, including the different modification methods, the various properties, and their advanced applications in different fields. Finally, the challenges and possible solutions were provided for future investigations of MGF.

High Value Utilization of Waste Wood toward Porous and Lightweight Carbon Monolith with EMI Shielding, Heat Insulation and Mechanical Properties.

With the increasing pollution of electromagnetic (EM) radiation, it is necessary to develop low-cost, renewable electromagnetic interference (EMI) shielding materials. Herein, wood-derived carbon (WC) materials for EMI shielding are prepared by one-step carbonization of renewable wood. With the increase in carbonization temperature, the conductivity and EMI performance of WC increase gradually. At the same carbonization temperature, the denser WC has better conductivity and higher EMI performance. In addition, due to the layered superimposed conductive channel structure, the WC in the vertical-section shows better EMI shielding performance than that in the cross-section. After excluding the influence of thickness and density, the specific EMI shielding effectiveness (SSE/t) value can be calculated to further optimize tree species. We further discuss the mechanism of the influence of the microstructure of WC on its EMI shielding properties. In addition, the lightweight WC EMI material also has good hydrophobicity and heat insulation properties, as well as good mechanical properties.

Research Progress of the Ion Activity Coefficient of Polyelectrolytes: A Review.

Polyelectrolyte has wide applications in biomedicine, agriculture and soft robotics. However, it is among one of the least understood physical systems because of the complex interplay of electrostatics and polymer nature. In this review, a comprehensive description is presented on experimental and theoretical studies of the activity coefficient, one of the most important thermodynamic properties of polyelectrolyte. Experimental methods to measure the activity coefficient were introduced, including direct potentiometric measurement and indirect methods such as isopiestic measurement and solubility measurement. Next, progress on the various theoretical approaches was presented, ranging from analytical, empirical and simulation methods. Finally, challenges for future development are proposed on this field.

Bio-Template Synthesis of V2O3@Carbonized Dictyophora Composites for Advanced Aqueous Zinc-Ion Batteries.

In terms of new-generation energy-storing devices, aqueous zinc-ion batteries (AZIBs) are becoming the prime candidates because of their inexpensive nature, inherent safety, environmental benignity and abundant resources. Nevertheless, due to a restrained selection of cathodes, AZIBs often perform unsatisfactorily under long-life cycling and high-rate conditions. Consequently, we propose a facile evaporation-induced self-assembly technique for preparing V2O3@carbonized dictyophora (V2O3@CD) composites, utilizing economical and easily available biomass dictyophora as carbon sources and NH4VO3 as metal sources. When assembled in AZIBs, the V2O3@CD exhibits a high initial discharge capacity of 281.9 mAh g-1 at 50 mA g-1. The discharge capacity is still up to 151.9 mAh g-1 after 1000 cycles at 1 A g-1, showing excellent long-cycle durability. The extraordinary high electrochemical effectiveness of V2O3@CD could be mainly attributed to the formation of porous carbonized dictyophora frame. The formed porous carbon skeleton can ensure efficient electron transport and prevent V2O3 from losing electrical contact due to volume changes caused by Zn2+ intercalation/deintercalation. The strategy of metal-oxide-filled carbonized biomass material may provide insights into developing high-performance AZIBs and other potential energy storage devices, with a wide application range.

Al Foil-Supported Carbon Nanosheets as Self-Supporting Electrodes for High Areal Capacitance Supercapacitors.

Self-supporting electrode materials with the advantages of a simple operation process and the avoidance of the use any binders are promising candidates for supercapacitors. In this work, carbon-based self-supporting electrode materials with nanosheets grown on Al foil were prepared by combining hydrothermal reaction and the one-step chemical vapor deposition method. The effect of the concentration of the reaction solution on the structures as well as the electrochemical performance of the prepared samples were studied. With the increase in concentration, the nanosheets of the samples became dense and compact. The CNS-120 obtained from a 120 mmol zinc nitrate aqueous solution exhibited excellent electrochemical performance. The CNS-120 displayed the highest areal capacitance of 6.82 mF cm-2 at the current density of 0.01 mA cm-2. Moreover, the CNS-120 exhibited outstanding rate performance with an areal capacitance of 3.07 mF cm-2 at 2 mA cm-2 and good cyclic stability with a capacitance retention of 96.35% after 5000 cycles. Besides, the CNS-120 possessed an energy density of 5.9 µWh cm-2 at a power density of 25 µW cm-2 and still achieved 0.3 µWh cm-2 at 4204 µW cm-2. This work provides simple methods to prepared carbon-based self-supporting materials with low-cost Al foil and demonstrates their potential for realistic application of supercapacitors.

Rhodamine-Anchored Polyacrylamide Hydrogel for Fluorescent Naked-Eye Sensing of Fe3.

A fluorescent and colorimetric poly (acrylamide)-based copolymer probe P(AAm-co-RBNCH) has been designed via free radical polymerization of a commercial acrylamide monomer with a rhodamine-functionalized monomer RBNCH. Metal ion selectivity of RBNCH was investigated by fluorescence and colorimetric spectrophotometry. Upon addition of Fe3+, a visual color change from colorless to red and a large fluorescence enhancement were observed for the ring-opening of the rhodamine spirolactam mechanism. The monomer gives a sensitive method for quantitatively detecting Fe3+ in the linear range of 100-200 µM, with a limit of detection as low as 27 nM and exhibiting high selectivity for Fe3+ over 12 other metal ions. The hydrogel sensor was characterized by FTIR, and the effects of RBNCH amount on gel content and swelling properties were explored. According to the recipe of 1.0 mol% RBNCH to the total monomers, the fabricated hydrogel sensor displayed a good swelling property and reversibility performance and has potential for application in the imaging of Fe3+ level in industrial wastewater.

Wood-Derived High-Mass-Loading MnO2 Composite Carbon Electrode Enabling High Energy Density and High-Rate Supercapacitor.

The simple design of a high-energy-density device with high-mass-loading electrode has attracted much attention but is challenging. Manganese oxide (MnO2 ) with its low cost and excellent electrochemical performance shows high potential for practical application in this regard. Hence, the high-mass-loading of the MnO2 electrode with wood-derived carbon (WC) as the current collector is reported through a convenient hydrothermal reaction for high-energy-density devices. Benefiting from the high-mass-loading of the MnO2 electrode (WC@MnO2 -20, ≈14.1 mg cm-2 ) and abundant active sites on the surface of the WC hierarchically porous structure, the WC@MnO2 -20 electrode shows remarkable high-rate performance of areal/specific capacitance ≈1.56 F cm-2 /45 F g-1 , compared to the WC electrode even at the high density of 20 mA cm-2 . Furthermore, the obtained symmetric supercapacitor exhibits high areal/specific capacitances of 3.62 F cm-2 and 87 F g-1 at 1.0 mA cm-2 and high energy densities of 0.502 mWh cm-2 /12.2 Wh kg-1 with capacitance retention of 75.2% after 10 000 long-term cycles at 20 mA cm-2 . This result sheds light on a feasible design strategy for high-energy-density supercapacitors with the appropriate mass loading of active materials and low-tortuosity structural design while also encouraging further investigation into electrochemical storage.

Thermal, Mechanical and Dielectric Properties of Polyimide Composite Films by In-Situ Reduction of Fluorinated Graphene.

Materials with outstanding mechanical properties and excellent dielectric properties are increasingly favored in the microelectronics industry. The application of polyimide (PI) in the field of microelectronics is limited because of the fact that PI with excellent mechanical properties does not have special features in the dielectric properties. In this work, PI composite films with high dielectric properties and excellent mechanical properties are fabricated by in-situ reduction of fluorinated graphene (FG) in polyamide acid (PAA) composites. The dielectric permittivity of pure PI is 3.47 and the maximum energy storage density is 0.664 J/cm3 at 100 Hz, while the dielectric permittivity of the PI composite films reaches 235.74 under the same conditions, a 68-times increase compared to the pure PI, and the maximum energy storage density is 5.651, a 9-times increase compared to the pure PI films. This method not only solves the problem of the aggregation of the filler particles in the PI matrix and maintains the intrinsic excellent mechanical properties of the PI, but also significantly improves the dielectric properties of the PI.

Highly Stretchable Composite Foams via Sustainable Utilization of Waste Tire Rubbers for Temperature-Dependent Electromagnetic Wave Absorption.

Recently, the sustainable utilization of waste resources has become a low-cost and effective strategy to design high-performance functional materials to solve the increasingly serious environmental pollution problem. Herein, the flexible and highly stretchable polyurethane (PU) composite foams assisted by one-dimensional carbon nanotubes (CNTs) and zero-dimensional Fe3O4 were fabricated using waste tire rubbers (WTRs) as reinforcements during a simple self-foaming process. The collaborative introduction of conductive CNTs, magnetic Fe3O4, and WTRs with three-dimensional cross-linked structures enabled the construction of an efficient electronic transmission path and heterointerfaces inside the composite foam. The resulting composite foam possessed a desired minimum reflection loss (RLmin) of −47.43 dB, and also exhibited superior mechanical properties with a tensile strength of >3 MPa and multiple tensile deformation recovery abilities. In addition, increasing the temperature could significantly improve the electromagnetic wave absorption performance of the composite foam. This comprehensive composite foam derived from WTRs has shown a promising development potential for using waste materials to relieve electromagnetic pollution.

Wood-Derived, Conductivity and Hierarchical Pore Integrated Thick Electrode Enabling High Areal/Volumetric Energy Density for Hybrid Capacitors.

For the proliferation of the supercapacitor technology, it is essential to attain superior areal and volumetric performance. Nevertheless, maintaining stable areal/volumetric capacitance and rate capability, especially for thick electrodes, remains a fundamental challenge. Here, for the first time, a rationally designed porous monolithic electrode is reported with high thickness of 800 µm (46.74 mg cm-2 , with high areal mass loading of NiCo2 S4 6.9 mg cm-2 ) in which redox-active Ag nanoparticles and NiCo2 S4 nanosheets are sequentially decorated on highly conductive wood-derived carbon (WC) substrates. The hierarchically assembled WC@Ag@NiCo2 S4 electrode exhibits outstanding areal capacitance of 6.09 F cm-2 and long-term stability of 84.5% up to 10 000 cycles, as well as exceptional rate capability at 50 mA cm-2 . The asymmetric cell with an anode of WC@Ag and a cathode of WC@Ag@NiCo2 S4 delivers areal/volumetric energy density of 0.59 mWh cm-2 /3.93 mWh cm-3 , which is much-improved performance compared to those of most reported thick electrodes at the same scale. Theoretical calculations verify that the enhanced performance could be attributed to the decreased adsorption energy of OH- and the down-shifted d-band of Ag atoms, which can accelerate the electron transport and ion transfer.

Robust Superamphiphobic Coatings Based on Raspberry-like Hollow SnO2 Composites.

Good mechanical and chemical stabilities are the key factors for the wide application of superhydrophobic surfaces. In this work, we first prepared raspberry-like hollow structured SnO2 nanoparticles using a simple hydrothermal method, followed by an annealing step. Then, the intrinsic raspberry-like hollow SnO2 nanoparticles were combined with hydrophilic SiO2 nanoparticles to construct rough surfaces with suitable hierarchical structures, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS-17) was used as a hydrophobic modifier of SnO2, while epoxy resin was used as an adhesive to prepare a superamphiphobic coating with good stability and durability. Such a coating can be applied on various substrates using a simple spray-coating or drop-coating method. The water contact angle and diiodomethane contact angle of the coating could reach up to ∼165 and ∼151°, respectively. After various chemical and mechanical stability tests including hot water treatment, salt water corrosion, strong adhesive tape peeling, and kneading, the coatings still remained amphiphobic. The facile fabrication of the robust superhydrophobic coating has great potential for applications in real life and industrial production.

Bismaleimide bridged silsesquioxane aerogels with excellent heat resistance: effect of sol-gel solvent polarity.

Due to the poor heat-resistance and intrinsic weakness of the bridging moieties in aerogel matrixes, it remains greatly challenging to fabricate highly thermostable and toughened silsesquioxane aerogels. By utilizing bismaleimide as the bridging part and optimizing the solvent polarity, lightweight (ρ < 0.09 g cm-3), compressible (80% strain) and superhydrophobic (CA ≈ 150°) bismaleimide bridged silsesquioxane aerogels (BMIT-BSAs) are constructed. The microstructure and compressive modulus of BMIT-BSAs can be tuned by the sol-gel solvents with different polarities. Moreover, stable low-temperature wettability at -196 °C and a significantly increased initial deposition temperature of 336 °C for both N2 and O2 atmospheres were measured, demonstrating the wide temperature tolerance of BMIT-BSAs.

Access to Substituted Thiophenes through Xanthate-Mediated Vinyl C(sp2)-Br Bond Cleavage and Heterocyclization of Bromoenynes.

An environmentally sustainable strategy for the chemoselective heterocyclization of bromoenynes through a transition-metal-free sulfuration/cyclization process is reported. Using inexpensive and safe EtOCS2K as a thiol surrogate and tetrabutylphosphonium bromide and H2O as a mixed solvent, the reaction provided a range of substituted thiophenes in moderate to good yields. In addition, 2,3,4,5-tetrasubstituted thiophenes were able to be prepared under mild reaction conditions by electrophilic heterocyclization with NH4I and EtOCS2K in good yields.