Sol-gel Strategy Research Articles

Silica gels doped with gold nanoparticles and gold thiolate complexes: The effect of heating and preparation conditions

A novel sol-gel strategy for the preparation of silica nanocomposites, containing gold nanoparticles (AuNPs), Au(I)-thiolate complexes (Au-SC12) or both disperse phases is demonstrated. The color of the species depends on the size and surrounding of the AuNPs. The nanocomposites obtained are characterized with UV/Vis reflectance spectroscopy, X-Ray diffraction, TEM / EDAX and thermal conductivity measurements. An analysis of the UV/VIS spectra, based on Mie's theory, suggests the presence of 5 - 30 nm AuNPs with different chemical surroundings. Heating of the nanocomposites at 700 °C leads to red or violet colored SiO2:AuNPs powders. The thermal conductivity of the nanocomposites is about 0.05–0.07 W/m.K, depending on sintering and chemical composition. A discussion about the microstructure of the composites is also presented.

Local Charge Modulation Induced the Formation of High‐Valent Nickel Sites for Enhanced Urea Electrolysis

AbstractNi‐based electrocatalysts are considered to be significantly promising candidates for electrocatalytic urea oxidation reaction (UOR). However, their UOR activity and stability are severely enslaved by the inevitable Ni group self‐oxidation phenomenon. In this study, the glassy state NiFe LDH with uniform Cu dopant (Cu‐NiFe LDH) by a simple sol–gel strategy is successfully synthesized. When served as the UOR catalyst, Cu‐NiFe LDH required a 123 mV lower potential for UOR at both 10 and 100 mA cm−2 in comparison with the conventional anodic OER. It can also operate steadily for more than 300 h at 10 mA cm−2. The in‐depth investigation reveals that Cu incorporation can optimize the local electronic structure of Ni species to induce high‐valent Ni sites. The high‐valent Ni sites would act as the active center during the proposed energetically favorable UOR route, which directly reacts on the high‐valent Ni sites without self‐oxidation inducing the formation of NiOOH species, resulting in a boosted electrocatalytic UOR activity and stability.

Synthesis and electrochemical properties of high entropy titanate powders (La0.2X0.2Ba0.2Sr0.2Y0.2)TiO3 (X = Na or K, Y = Ca or Pb) with perovskite structure

In this paper, four new high entropy titanate powders (La0.2X0.2Ba0.2Sr0.2Y0.2)TiO3 (X = Na or K, Y = Ca or Pb) were successfully synthesized by a sol‒gel strategy. When the pH value of the sol ranged from 3 to 4, it was easier to obtain pure high entropy powders with a perovskite structure. When the calcination temperature was in the range of 700 °C–900 °C, the high entropy powders were more beneficial to form a single solid solution with high XRD diffraction intensity and crystal quality. The as-synthesized powders with uniform distribution of A-position elements had a particle size between 50–120 nm and good dispersibility. The cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) tests showed that these powders had better electrochemical properties and energy storage potential. When the discharge current was 1 A/g, the specific capacitance was higher than 136 F/g, even if the current density was 10 A/g, the specific capacity remained about 60 % of the initial.

Magnetic media synergistic carbon fiber@Ni/NiO composites for high-efficiency electromagnetic wave absorption

Electromagnetic wave (EMW) absorbing materials have garnered significant attention for their potential applications in information security and military stealth fields. However, the development of highly efficient EMW absorbing materials possessing characteristics such as being “thin, lightweight, broadband and strong” remains a considerable challenge. Addressing this challenge involves the construction of low-dimensional composite material systems, which proves to be an effective approach. In this study, we developed a simple and innovative sol–gel strategy to fabricate carbon fiber (CF)@Ni/NiO composites. The results demonstrate that the incorporation of Ni/NiO particles into CF materials substantially enhances the ferromagnetic properties of CF@Ni/NiO composites. An optimum reflection loss (RL) of CF@Ni/NiO-3 is −55.58 dB at 15.4 GHz with a corresponding thickness of merely 1.7 mm. An effective absorption bandwidth (EAB) reaches a maximum of 6.0 GHz at a thickness of 1.8 mm. Meanwhile, the radar cross section (RCS) reduction value at 6 GHz reaches 29.92 dB m2. The uniform distribution of Ni/NiO nanoparticles not only establishes a magnetic coupling network but also creates abundant heterogeneous interfaces with CF, thereby enhancing interfacial polarization. The successful fabrication of CF@Ni/NiO composites will facilitate the development and broad application of advanced EMW absorption materials in the aviation and aerospace sectors.

Cost-effective synthesis of stable CoxC@few-layered graphene nanostructures embedded in a carbon matrix

In this study, a two-step surfactant sol-gel strategy is developed to synthesize Co particles with confined sizes in the nanoscale using organic precursors. This approach does not require the use of vacuum techniques or strong reducing atmospheres, making it a simple approach economically attractive. The strategy involves the generation of few-layered graphene shells to provide chemical stability, prevent oxidation and aggregation tendencies. Additionally, the study investigates the use of precursors based on nitrates and acetates, exploring their structural and magnetic properties in densified samples. Remarkably, magnetic properties are competitive for both approaches, with coercivities reaching up to 300 Oe and saturation magnetization of ∼60 and ∼80 emu/g for samples based on nitrates and acetates prepared at 650 °C, respectively. However, it is observed that smaller and more uniformly sized nanoparticles (around ∼10 nm) are obtained with nitrate-based precursors due to an effective ligand decomposition process. Therefore, this chemical approach offers effective nanoscale confinement with intriguing magnetic properties through a cost-effective and reproducible synthesis.

A sol-gel strategy for constructing a hydroxyapatite nanowire/aramid nanofiber electric insulating composite with excellent flame retardancy and mechanical property

With the increasing demand for high power and miniaturization of modern large-scale electrical equipment, preparing high-performance electrical insulation materials with high thermal stability and excellent mechanical properties has become an urgent problem. In this study, hydroxyapatite (HAP) nanowires and aramid nanofibers (ANF) multifunctional composites were prepared by sol-gel-membrane strategy. Aramid fibers containing an amide structure and HAP can form an ordered hydrogen bonding network and exhibit strong hydrogen bonding. The prepared HAP/ANF nanocomposite films with nanowire/nanofiber network skeleton and laminate structure have good tensile strength (69.6 MPa), dielectric breakdown strength (65.7 kV mm−1), and processing properties. Particularly emphasized is that the multifunctional HAP/ANF nanocomposite films are fireproof and high-temperature resistant, and the interfacial hydrogen-bonding enhancement between HAP nanowires and aramid fibers facilitates the construction of multifunctional insulating materials.

Dynamically Reversible Gelation of Electrolyte for Efficient Wide‐Temperature Adaptable Energy Storage

AbstractQuasi‐solid‐state electrolytes (QSEs) via gelation of liquid electrolytes (LEs) are perspective protocols for constructing ingenious potassium‐ion batteries (PIBs) due to the combined advantages of both liquid and solid state. However, most of QSEs yet researched face a trade‐off among low temperature adaptability and safely high temperature operation. Herein, in situ reversible gelation of Ni‐crosslinked pentaerythritol tetrakis (3‐mercaptopropionate) (PETMP‐Ni) co‐polymerized with tyramine‐modified hyaluronic acid (HA‐Tyr) (PHA) modified B, N modified carbon spheres (BNC) enclosing by red P (RP) is backed with compatible electrode‐electrolyte interface with laponite filler (L). Such high reversible in situ gelation displays high low temperature adaptability by LEs, and extraordinary safety in high temperature steered by QSEs, benefiting from topologic space crowding effect (TSCE) and reverse trap of Ni single atoms (Ni SAs). This work enlightens the missing prospects in constructing reversible in situ sol–gel strategy coupled by topologic space crowding effect and reverse SAs trapping stimulate toward revival hybrid electrode for wide‐temperature adaptive batteries.

Construction and modularization of porous sulfur-doped carbon nitride nanotubes with excellent photocatalytic activity and potential engineering application value

In this paper, we successfully fabricate a porous sulfur-doped carbon nitride nanotubes (p-C3N4-xSx NTs) for the first time with melamine (C3H6N6), trithiocyanuric acid (C3H3N3S3), and sodium chloride (NaCl) as precursors by a simple thermal polymerization strategy. The doping of sulfur element and the construction of porous nanotube microstructure can effectively improve the transmission efficiency of photogenerated electrons in p-C3N4-xSx NTs. Therefore, the as-prepared p-C3N4-xSx NTs shows excellent visible-light photocatalytic performance in the photocatalytic reactions of hydrogen peroxide (H2O2) production and Rhodamine B (RhB) degradation. The proposed micro-path indicates that C3H3N3S3 acts as both sulfur source and pore-forming agent, while NaCl acts as the structural guide agent to form tubular nanostructures during p-C3N4-xSx NTs preparation. In addition, we also successfully prepare modular p-C3N4-xSx NTs@SA with potential engineering application value through a simple sol-gel strategy by using sodium alginate (SA) as a precursor in order to solve the difficult problem of separation and recovery of powder photocatalysts.

Synthesis of novel MOF-on-MOF composite as a magnetic sorbent to dispersive micro solid phase extraction of benzodiazepine drugs prior to determination with HPLC-UV

Diazepam and lorazepam are two benzodiazepine drugs widely prescribed as antidepressants and antiepileptics. A straightforward and time-save dispersive micro solid phase extraction method as a sample preparation strategy was developed to extract these drugs in human urine and real water samples prior to their determination by HPLC-UV. A novel sorbent based on growing Co-MOF on Fe-MOF was synthesized and then magnetized using magnetic Fe3O4 nanoparticles and a sol–gel strategy. The sorbent (Fe3O4@SiO2@Co-MOF@Fe-MOF composite) showed the highest extraction efficiency toward diazepam and lorazepam compared to Fe-MOF and Co-MOF@Fe-MOF as sorbents. The effects of various factors on diazepam and lorazepam determination were studied by experimental design, in which a Plackett-Burman design and Box-Behnken design were used for screening the factors and optimizing the significant factors, respectively. Under optimum conditions, the method linearity for the diazepam and lorazepam determination was 0.3–450 and 0.2–400 ng mL−1 with an R2 of 0.9926 and 0.9943, respectively. Proper detection limits of 0.09 and 0.06 ng mL−1 were obtained for the diazepam and lorazepam determination. Also, intra-day and inter-day RSDs (n = 3) were in the range of 3.42–3.75 % and 4.76–5.39 % for the diazepam and lorazepam determination, respectively. The method exhibits a high preconcentration factor of 654.3 and 719.1 for the diazepam and lorazepam determination. Besides, the recoveries and RSDs were evaluated by analysis of tap, river, and well water, and two human urine samples using the method. RSDs were in the range of 3.09–6.80 %, with recoveries between 88.2 and 97.5 % for analysis of spiked real water and urine samples.

Hybrid mesoporous silica materials templated with surfactant polyion complex (SPIC) micelles for pH-triggered drug release

New Surfactant PolyIon Complex (SPIC) micelles were assembled by electrostatic complexation of an antibacterial cationic surfactant, cetylpyridinium chloride (CPC), and a double hydrophilic block copolymer (DHBC) containing a neutral comb block of poly(oligo(ethylene glycol)) methyl ether acrylate (PEOGA) and a weak polyacid block of poly(acrylic acid) (PAA). The corresponding SPIC micelles, with a CPC/PAA core and a PEOGA corona, were successfully used as structure directing and functionalizing agents in a soft and sustainable sol-gel strategy, yielding hybrid mesoporous silica (MS) materials with a monomodal pore size distribution centred at 2.8 nm. The influence of synthesis parameters, including the pH, concentrations and ratios of components, was systematically investigated. The obtained hybrid MS materials were intrinsically functional, with PEOGA blocks anchored in silica walls via H-bonding, while weak polyacid blocks, complexed with CPC, were confined within the mesopores. The response of the materials to pH changes (pH 7.4, 4.2 and 3) indicated remarkable stability of the anchored DHBC, while CPC was selectively released under the acidic conditions typical of orodental biofilm microenvironments. This result is noteworthy, since the release of encapsulated amphiphilic drugs into water is less favorable than that of hydrophilic drugs. Owing to the control of their pore and functionality properties, ordered hybrid silica materials templated and functionalized with SPIC systems will be materials of choice for developing pH-responsive biomedical devices using wet processing techniques.

Porous polypyrrole Nanotube-Based Organohydrogels: Versatile materials for robust electromagnetic interference shielding in harsh environments

Wearable and multi-functional electromagnetic interference (EMI) shielding materials are an inevitable trend in order to cope with increasingly complex practical applications. In the present work, polypyrrole nanotube (PNT)-based organohydrogels (POGs) with excellent electromagnetic shielding effectiveness (SE) were synthesized through a facile sol–gel strategy. The obtained POGs offer distinct shielding performance, anti-drying, anti-freezing, plasticity and recyclable ability. The POG with a 20 wt% PNTs filling exhibits a SET of 63.6 dB in the X-band at a thickness of 2.0 mm. After being placed at ambient temperature for 30 days and − 40 ℃ for 4 h, its SE values still retained at 50.3 dB and 59.3 dB, respectively. Moreover, after being immersed in the solvents, the POG (left in the air for 30 days) can recover flexibility and 92 % of its original EMI shielding performance. Importantly, crushing the fully dried organohydrogels into the powder and placing it again in the solvents fully restores its flexibility and EMI shielding properties. The glorious shielding and mechanical characteristics can be ascribed to the superior conductivity of PNTs and the highly crosslinked stable network of PVA, as well as the further enhancement of the crosslinked network by cellulose nanofibers. In addition, ​sensors based on POGs can effectively detect human movement and strain deformations. This work thus provides fresh insight into exploring the sustainability of flexible and wearable EMI shielding materials for handling extreme environments.

Development of a disposable hollow fibre-solid phase microextraction device using chitosan functionalised MWCNTs and a polyoxometalate for the simultaneous extraction of angiotensin II receptor blocker drugs

ABSTRACT Valsartan and Losartan are two angiotensin II receptor blocker drugs used to treat heart failure and high blood pressure. A straightforward and disposable hollow fibre-solid phase microextraction device was developed to extract these drugs from real water and urine samples. A green sorbent was synthesised by functionalised MWCNTs with chitosan through a chemical route method. Besides, a polyoxometalate (Ni-CoWO4 nanoparticles) was prepared as a modifier using the hydrothermal procedure. Using the sol-gel strategy, the sorbent and modifier were reinforced in the hollow fibre pores and lumen. The approach leads to an increase in the sorbent coating stability on/in hollow fibre. The influential factors were optimised with an experimental design, indicating that pH, extraction time, and desorption time significantly affect the Valsartan and Losartan extraction. The linearity of the method to determine Valsartan and Losartan was 3.4–1850 and 3.1–1800 ng mL−1, with R squared of 0.9929 and 0.9947, respectively. The detection and quantification limits were lower than 0.9 ng mL−1 and 3.4 ng mL−1, respectively. The pre-concentration factors for determining Valsartan and Losartan with a concentration of 20 ng mL−1 were 654.2 and 546.3, respectively. The intra-day and inter-day RSDs were lower than 3.11% and 3.87% for measuring Valsartan and Losartan. The recoveries and RSDs for analysing spiked eal water and urine samples were between 91.8–97.8% and 3.16–4.10%, respectively.

Synthesis of Single Crystalline Spike Shaped Nano-Rod Structured Cathode for High Performance SIB

The increasing need for energy, the widespread adoption of electric vehicles and renewable energy storage systems, and the search for cost-effective, reliable energy storage options are all factors in the dynamic nature of the global energy landscape and energy storage industry. As more and more people switch to using electric vehicles and other kinds of renewable energy storage, there has been a corresponding increase in demand for LIBs all around the globe. Despite increasing demand, there are geopolitical and supply-chain risks as most LIBs are still manufactured in only a few countries, namely China, Japan, and South Korea. Sodium-ion batteries, also known as SIBs, have recently come to the forefront as a potentially advantageous candidate for the large-scale storage of electric energy due to the potential advantages of widespread availability and low cost of sodium resources. SIB research and development are still at an early stage, and there are few opportunities for their commercialization. SIBs do, however, confront a number of issues that need to be addressed, including as their short cycle life and rate capability, the restricted availability of high-performance materials, and the need for more research and development to maximize their performance and dependability. Nonetheless, tremendous progress has been made recently, and several businesses and research centers across the globe are attempting to enhance SIB technology. The high theoretical specific capacity and quantity of component elements make layered metal oxides suitable cathode materials for SIBs. In order to enhance their electrochemical performance, however, further exploration is required to deal with their drawbacks, such as limited rate capability and voltage fading. As the cathode materials play such a large role in determining the energy density of SIBs, the primary issue in developing high-energy SIBs is discovering cathode materials with plentiful active sites, high reaction potential, unhindered ionic channels, and stable structures. Tailoring the morphology of materials using nanostructure engineering opens up hitherto unimagined possibilities for exploiting the functional features such as enhanced electrode's specific surface area, decreased sodium-ion diffusion distance, and boost in electronic conductivity. This study demonstrates a quaternary 1D layered transition metal oxide-based cathode with a composition of Na0.67Fe0.25Mn0.5Ti0.2V0.05O2 synthesized by a facile sol-gel strategy. From the SEM results, it is seen that 1D spoke like nanorods are evolved with a tiny fraction of 3D hexagonal lattice which is due to the excessive presence of vanadium in the stoichiometry ratio of the composite. Such nanorod framework configuration facilitates large surface area in contact with the electrolyte that is suitable for charge migration and rapid diffusion of sodium ions through short solid-state route. The P2- Na0.67Fe0.25Mn0.5Ti0.2V0.05O2 microstructure, with its high crystallinity and nanorod structure, showed off a high specific capacity and outstanding rate capability which is visible through electrochemical analysis results.

Sol-gel synthesis, physico-chemical characterization and investigations on ion exchange performance of atypical conducting polymer integrated composite cation exchangers

ABSTRACT Herein, an effective sol-gel strategy was utilized for the synthesis of atypical Polypyrrole/EDTA-Zirconium(IV) phosphate (PYZP) and Polypyrrole/EDTA-Zirconium(IV) iodate (PYZI) composite cation exchangers. The structural aspects, surface morphology, elemental composition and thermal constancy of the aforementioned composite cation exchangers were scrutinized through UV-Visible, FT-IR, XRD, SEM with EDAX, TEM and TGA studies. As-prepared conducting polymeric composite materials divulged not only excellent ion exchange capacity but also better thermal stability, electrical conductivity and notable selectivity toward Pb(II) ions as compared to their individual inorganic moieties. The improvement in ion exchange capacities (IEC) for distinct alkali metal ions of PYZP composite cation exchanger were Li+, 2.89; Na+, 3.15; K+, 3.34 meq/g and PYZI composite cation exchanger were Li+, 2.60; Na+, 2.86; K+, 3.21 meq/g, separately. It was concluded that PYZP composite acts as an excellent cation exchanger compared to PYZI composite due to the presence of ionogenic phosphate anions. The partition competency of the composite materials toward distinct metal ions in diverse solvent systems exposed the separation potentials of metal ions of systematic prominence from a specified binary combinations encompassing Cd(II) – Pb(II), Hg(II) – Pb(II), Cu(II) – Pb(II), Zn(II) – Pb(II), Ni(II) – Pb(II) and Fe(III) – Pb(II) metal ions. Subsequently, the conducting competency was examined through AC-Impedance spectroscopy.

Construction of anchor points in metal-organic framework-based membranes for high flux separations and high-efficient anticancer drug intermediates capture

Mixed matrix membranes (MMMs) have attracted tremendous attentions as valuable materials to realize energy-efficiency micro-molecule separation. Nonetheless, traditional MMMs inevitably faced low-level substrate-polymer interfacial consistency, functional loadings agglomeration, limited attachment of active reactor and so on, causing poor selectivity of molecular transport in nanochannels. Herein, incorporating ideas from mussel biomimetic chemistry, a bottom-up approach was developed for in situ assembling nanosized metal–organic frameworks (MOFs) in polydopamine-adhesive nanoparticles, followed by boron-affinity sol–gel strategy driven anchoring points formation in electrospinning nanofiber membranes to achieve effectively separate shikimic acid (SA) with great medicinal value. Our approach simultaneously improved permeability and selectivity for the membrane adsorbent to nanoscale molecules, and superior SA affinity stability was maintained even during long-term cyclic tests that of only less than 14.97% of rebinding selective capacity loss and 9.83% of perm-selectivity damage. In addition, the antifouling durability as well as antibacterial persistence were retained with ultrahigh UiO-66-functionalized polydopamine (PDA)-connected nanoparticle loadings. This symbiosis-driven de novo strategy could potentially draw bright blueprint for burgeoning MMMs that could realize precise separation to molecules of medical value.

Membrane adsorbers with ultrahigh metal–organic framework loading for high flux selective separations to isomer

Membrane-based separation processes have received significant attention as promising schemes realizing energy-efficiency micro-molecule separation. However, traditional Mixed Matrix Membranes (MMMs) inevitably faced the restriction that of low-level substrate-polymer interfacial consistency, functional loaders agglomeration, instability under long-term reaction and so on, causing it extremely challengeable to construct high-performance membrane-based separation system. Here, incorporating ideas of mussel biomimetic chemistry, a 3D nano-hybrid seeding strategy was designed for in situ assembling nanosized zeolitic imidazolate frameworks (ZIFs) to polydopamine-adhesive nanofibers, followed by the construction of specific imprinting sites within nanofiber membranes driven by boron-affinity sol–gel strategy, which achieved high-efficiency selective separation to shikimic acid (SA) with great medicinal value. This strategy simultaneously improved permeability and selectivity of separation membrane to nanoscale molecules. And superior SA affinity stability was maintained with the ultrahigh ZIF-8 loadings (73 %) even during long-term cyclic tests, where only less than 10.09 % of rebinding selective capacity loss and 6.50% of perm-selectivity damage existed. In addition, the antifouling durability as well as antibacterial persistence were obtained due to ZIF-8-functionalized polydopamine (PDA)-connected nanofibers construction. This symbiosis-inspired de novo strategy could promisingly draw bright blueprint for burgeoning MMMs to realize specifical separation of molecules with medical value against isomer mixture.

Bioinspired SiO2/PDA/PTFE membrane with high corrosion-resistance for long-term efficient oil/water separation

Oil spills and oily wastewater from various industries caused severe harm to the environment and human life. Then the effective treatment of oily wastewater is extremely urgent. Superhydrophilicity/underwater superoleophobicity membranes are considered as a favorable choice for the separation of oily wastewater. In this work, inspired by mussel adhesive protein chemistry, the SiO2/PDA/PTFE membrane (SPP) with hydrophilic chemical components and multi-scale rough structures was prepared by the facile combination of dopamine self-polymerization and sol-gel strategy. The hydrophilic SiO2 nanoparticles (NPs) and polydopamine layer can be co-deposited on the membrane surface through Michael addition reaction, thus avoiding the problem of coating damage during oil/water separation. Moreover, the SiO2/PDA layer has hydrophilic groups and micro/nano rough structure, which makes the SPP membrane possess superhydrophilic and underwater superoleophobic properties. The properties of SPP membrane facilitate the formation of a hydration layer on the membrane surface, thus minimizing direct contact with oil droplets. During the experiment of oil/water separation, SPP membrane demonstrated excellent separation ability, the permeation flux of SPP membrane was measured to be 6183 and 4389 L m−2 h−1 for oil-water mixture and oil-in-water emulsion, respectively. The oil/water separation efficiency had also reached more than 99.7%. In addition, the SPP membrane exhibited brilliant chemical stability under harsh environments. It is worth mentioning that the SPP membrane showed superior cycling and anti-fouling performance in the separation process. These excellent performances demonstrate the great potential of SPP membranes in the industrial applications.

Proton Conducting Organic-Inorganic Composite Membranes for All-Vanadium Redox Flow Battery.

The quest for a cost-effective, chemically-inert, robust and proton conducting membrane for flow batteries is at its paramount. Perfluorinated membranes suffer severe electrolyte diffusion, whereas conductivity and dimensional stability in engineered thermoplastics depend on the degree of functionalization. Herein, we report surface-modified thermally crosslinked polyvinyl alcohol-silica (PVA-SiO2) membranes for the vanadium redox flow battery (VRFB). Hygroscopic, proton-storing metal oxides such as SiO2, ZrO2 and SnO2 were coated on the membranes via the acid-catalyzed sol-gel strategy. The membranes of PVA-SiO2-Si, PVA-SiO2-Zr and PVA-SiO2-Sn demonstrated excellent oxidative stability in 2 M H2SO4 containing 1.5 M VO2+ ions. The metal oxide layer had good influence on conductivity and zeta potential values. The observed trend for conductivity and zeta potential values was PVA-SiO2-Sn > PVA-SiO2-Si > PVA-SiO2-Zr. In VRFB, the membranes showcased higher Coulombic efficiency than Nafion-117 and stable energy efficiencies over 200 cycles at the 100 mA cm-2 current density. The order of average capacity decay per cycle was PVA-SiO2-Zr < PVA-SiO2-Sn < PVA-SiO2-Si < Nafion-117. PVA-SiO2-Sn had the highest power density of 260 mW cm-2, while the self-discharge for PVA-SiO2-Zr was ~3 times higher than Nafion-117. VRFB performance reflects the potential of the facile surface modification technique to design advanced membranes for energy device applications.

A novel sol-gel strategy for constructing wood fibers and aramid nanofiber nanocomposite with strong, tough and recyclable properties

Recently, biomass-based materials derived from wood processing residues have been developed to resolve the white pollution. However, the poor mechanical strength, weak water resistance, and non-recyclability still limit their practical applications. Aramid nanofiber (ANF) is a promising reinforcement due to the unique structural characteristics and exceptional mechanical properties. Here, a high-performance wood fibers-based nanocomposite was assembled based on chemically-modified wood fiber (CWF) and ANF via a sol-gel strategy with the solvent exchange. The dynamic noncovalent cross-linking with 3D reticular networks between CWF and ANF endow the as-prepared film with high tensile strength of 591.96 ± 11.05 MPa, high toughness of 38.68 ± 2.15 MJ/m3, and excellent solvent resistance. Moreover, the CWF-ANF gel can effectively repair the fractured CWF-ANF film under heating and maintain competitive mechanical properties after several dissolution-reconstruction, which shows the fascinating sustainability potential. Simultaneously, the as-prepared film is considered as a strong substrate to advance excellently conductive and anti-counterfeiting composite with double-layered structures. This effective strategy provides a novel pathway to reuse plant waste resources with competitive mechanical properties and high value-added utilization.

Composition of Organically Modified Silica for the Superhydrophobic Surface with Low Sliding Angle

Extremely water-repellent surfaces with low sliding angle (SA) have been obtained with a facile single-step sol-gel strategy via co-condensation of tetraethoxysilane (TEOS) and hexadecyltrimethoxysilane (HDTMS) in basic media with an efficient self-cleaning property. We investigated the effect of the molar ratio of HDTMS and TEOS on the properties of the modified silica-coated poly(ethylene terephthalate) (PET) film. A high water contact angle (WCA) of 165° and a low SA of 1.35° were obtained at a molar ratio of 0.125. The dual roughness pattern for the low SA was developed by a one-step coating of the modified silica with a molar ratio of 0.125. The evolution of the surface to the dual roughness pattern by nonequilibrium dynamics depended on the size and shape factor of modified silica. The primitive size and the shape factor of the organosilica with a molar ratio of 0.125 were 70 nm and 0.65, respectively. We also presented a new method to determine the superficial surface friction (ζ) of the superhydrophobic surface. The ζ was a physical parameter that characterized the slip and rolling behavior of water droplets on the superhydrophobic surface along with the equilibrium property WCA and the static frictional property SA.