The catalytic effect of rare-earth hydrogen storage alloy is investigated for dehydrogenation of alane, which shows a significantly reduced onset dehydrogenation temperature (86 °C) with a ...high-purity hydrogen storage capacity of 8.6 wt% and an improved dehydrogenation kinetics property (6.3 wt% of dehydrogenation at 100 °C within 60 min). The related mechanism is that the catalytic sites on the surface of the hydrogen storage alloy and the hydrogen storage sites of the entire bulk phase of the hydrogen storage reduce the dehydrogenation temperature of AlH3 and improve the dehydrogenation kinetic performance of AlH3. This facile and effective method significantly improves the dehydrogenation of AlH3 and provides a promising strategy for metal hydride modification.
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•The dehydrogenation performance of the LaNi5-doped AlH3 was investigated.•The onset dehydrogenation temperature of the composite decreased to 86 °C.•The composite released 6.3 wt% of hydrogen within 60 min at 100 °C.•The mechanism was provided according to the characterization.
In this work, the solid-liquid phase equilibria of griseofulvin (GSF) in three binary solvent systems were investigated by both experimental and molecular dynamic simulation approaches. The ...equilibrium solubility of griseofulvin (GSF) in three binary solvent mixtures of isopropanol + acetone, isopropanol + 2-butanone, and isopropanol + 4-methyl-2-pentanone was determined by the gravimetric method at temperatures ranging from 283.15 K to 323.15 K under atmospheric pressure. The equilibrium solubility increases monotonously as the temperature increases at a given solvent composition or increases with increasing the solvent composition of good solvent acetone (2-butanone) in binary solvent mixtures, whereas there exists a maximum solubility value in isopropanol + 4-methyl-2-pentanone system. These solubility behaviors were found complying well with the empirical rule “like dissolves likes”. The experimental data were then correlated by the modified Apelblat equation, λh equation, modified Jouyban-Acree equation, and NRTL model, and the modified Apelblat equation receives the best fitting performance. Moreover, the thermodynamic functions including enthalpy, entropy, and Gibb free energy of mixing were derived and expectedly suggested an exothermic and spontaneous process of mixing. Molecular dynamic (MD) simulation was further employed to investigate the solute-solvent interactions behind the dissolution behaviors of griseofulvin. Radial distribution function (RDF) analysis reveals that the rank of solute-solvent interactions can be well correlated with solubility order in binary solvent mixtures and the intermolecular interactions between solute molecules and good solvent molecules are dominant. All the thermodynamic data and models presented here will certainly provide fundamental basis for designing and optimizing the crystallization of griseofulvin, a classic antifungal drug. Our MD simulation results are also helpful to understand the solid-liquid phase equilibrium behaviors in binary solvent systems.
The local structure of solvation and binding tendency of griseofulvin in isopropanol + acetone binary solvent mixtures at different solvent compositions of isopropanol were explored by radial distribution function (RDF) to examine the strength of solute-solvent interactions, which reveals that the rank of solute-solvent interactions correlates well with solubility order in binary solvent mixtures. Display omitted
•Solubility of griseofulvin was measured by static method in three binary solvent mixtures.•Four thermodynamic models were used to correlate the solubility data.•Thermodynamic properties were analyzed by mixing functions.•Solute-solvent interactions were analyzed by radial distribution function (RDF).
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•Through vacuum arc melting, a series of Cu doping Ti-Mn-based AB2-type alloys are obtained.•Cu doping enlarges the crystal cells of the alloys and increases the hydrogen storage ...capacity of the alloys.•The alloys with Cu doping can improve the activation performance, reduce hysteresis coefficient and optimize cycle life.•First-principles Simulations prove that Cu doping is beneficial to the hydrogen storage properties.•The introduction of Cu to optimize the properties of hydrogen storage alloys is universal.
The Ti-Mn-based AB2-type hydrogen storage alloy has been widely researched and applied because of their higher hydrogen storage capacity, appropriate service temperature and low cost. However, before this hydrogen storage material becomes a mature technology, the essential issues of activation difficulty and high plateau pressure in hydrogen absorption/desorption process, need to be completely reformed by radical transformation in composition design and structure optimization. This work investigates the microstructure and hydrogen storage performances of Ti0.8Zr0.2Mn0.92Cr0.87Fe0.21 + x Cu (x = 0, 3, 5 and 8 wt%) by vacuum arc melting. Profiting from the excellent hydrogen transfer rate and structure optimization, the Ti0.8Zr0.2Mn0.92Cr0.87Fe0.21 alloys with the increasing of Cu doping result in the unique C14 Laves phase with the increased lattice volume. As a beneficial result, the decrease of the hydrogen absorption platform of Ti0.8Zr0.2Mn0.92Cr0.87Fe0.21 + 8 wt% Cu alloy is accompanied by the increase of the hydrogen desorption platform, thereby reducing the overall hysteresis coefficient of the material. Through Van't Hoff thermodynamic calculation results, it is found that the absolute values of hydrogenation enthalpy and entropy increase with the increasing of Cu doping. It is crucial to doping Cu inside the alloy by the accurate control of stoichiometric proportion and Cu content, which can improve the hydrogen storage performance of the alloy through theoretical analysis and First-principles simulation. This attempt enables new insights into the optimization of the hydrogen storage properties of Ti-Mn-based AB2-type hydrogen storage alloy, which can be generalized to the design of other new hydrogen storage materials.
The high dehydrogenation temperature of aluminum hydride (AlH
) has always been an obstacle to its application as a portable hydrogen source. To solve this problem, lithium nitride is introduced into ...the aluminum hydride system as a catalyst to optimize the dehydrogenation drastically, which reduces the initial dehydrogenation temperature from 140.0 to 66.8 °C, and provides a stable hydrogen capacity of 8.24, 6.18, and 5.75 wt.% at 100, 90, and 80 °C within 120 min by adjusting the mass fraction of lithium nitride. Approximately 8.0 wt.% hydrogen can be released within 15 min at 100 °C for the sample of 10 wt.% doping. Moderate dehydrogenation temperature slows down the inevitable self-dehydrogenation process during the ball-milling process, and the enhanced kinetics at lower temperature shows the possibility of application in the fuel cell.
Herein, carbon-coated MnO QDs decorated on a graphene aerogel (GA, C@MnO QDs/GA) were fabricated by forming a manganese oxide gel in situ on the GA, followed by supercritical drying and ...carbonization. The composite combines the uniform distribution of ultra-small MnO QDs and the conducting GA with the 3D porous interconnected network structure. The well-dispersed tiny MnO quantum dots can buffer the volume change and shorten the ion diffusion path to improve the reaction kinetics. The GA can provide a 3D conductive channel for rapid electron transfer and Li+ diffusion. When used as anodes for Li-ion batteries, C@MnO QDs/GA electrodes displayed superior electrochemical performance, such as ultra-high discharge capacity, excellent cycling stability, and outstanding rate performance. A high discharge capacity of 1698 mA h g–1 was delivered after 100 cycles at 200 mA g–1, and a capacity of 702 mA h g–1 can be retained at a high current density of 2000 mA g–1. The results suggest that the C@MnO QDs/GA materials designed in this work can be potential anodes for high-performance LIBs, providing meaningful implications for further exploration of oxide anodes for next-generation alkali metal-ion batteries.
The structure and properties of griseofulvin (GSF) were investigated in both solution and solid phases. The intermolecular interactions within griseofulvin crystal structure probed by Hirshfeld ...surface analysis reveal that the H⋯H and O⋯H contacts apparently dominate in the solid-state structure. The solution thermodynamic properties including solid-liquid phase equilibrium solubility and thermodynamic functions of mixing were determined in twelve solvents (methanol, ethanol, n-propanol, n-butanol, isobutanol, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, isopropyl acetate, isobutyl acetate and acetonitrile). The equilibrium solubility data was measured by gravimetric method at temperature ranging from 283.15 to 323.15 K, and the measurement results show the solubility is monotonously rising with increasing temperature as expected in all solvents. Besides, the investigations over the effect of solvent properties in terms of solvent polarity, hydrogen bonding donor and acceptor propensity, as well as cohesive energy density on solid-liquid phase equilibrium behaviors reveal that the solvent polarity determines the solubility of griseofulvin in the studied solvent systems. Further, the statistical correlations were well performed by the modified Apelblat equation, λh equation, and NRTL model, in which the modified Apelblat equation receives the best fitting performance. Finally, thermodynamic functions of mixing (enthalpy, entropy, and Gibbs energy) were derived, and the results suggest a spontaneous, exothermic and entropy-driven mixing process. All the thermodynamic data and models presented here will certainly provide fundamental basis for separation and purification of griseofulvin in industrial production.
The crystal structure analysis reveals that the H⋯H and O⋯H contacts apparently dominate in the solid-state structure and the solubility of griseofulvin is monotonously rising with increasing temperature in all the twelve mono-solvents. The solubility spectra reveal that the solvent polarity plays a key role in the solid-liquid phase equilibrium behavior of griseofulvin in the studied solvent systems. Display omitted
•The equilibrium solubility of griseofulvin was determined by the static method in twelve mono-solvents.•The intermolecular interactions within crystal structure were probed by Hirshfeld surface analysis.•The effect of solvent properties on solid-liquid phase equilibrium of griseofulvin was investigated.•Thermodynamic analyses were performed on the basis of thermodynamic functions of mixing.
The dispersibility of silica sol particles modified by γ-methacryloxy propyl trimethoxyl silane (γ-MPS) in an ethanol–water mixed solvent was investigated. In the modification process, the ...hydrolysate of γ-MPS condensed to form oligomers, which further formed hydrogen bonds with the hydroxyl groups on the surface of the silica sol particles to cause agglomeration. Increasing the ethanol concentration inhibited the hydrolysis of γ-MPS and the formation of oligomers, thus inhibiting the agglomeration of silica sol particles. When the ethanol concentration was above 74 wt%, the γ-MPS-modified silica sol slurry was transparent and with a TEM image in a single-particle dispersed state. The dispersibility of the silica sol particles was determined by a double electric layer repulsion mechanism before modification and a steric hindrance mechanism by organic molecules grafted on the surface of the particles after modification. The grafting density of γ-MPS on the surface of silica sol particles affected the hydrophobicity of the modified particles, which can be effectively controlled.
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•High ethanol concentration facilitates high dispersibility of particles.•High ethanol concentration inhibits γ-MPS hydrolysis and particle agglomeration.•Modified particles are single-particle dispersed by steric-hindrance.•Particle hydrophobicity has a positive correlation with γ-MPS grafting density.
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•The AlH3 catalyzed by Ti3C2@Pt is prepared facilely in short time.•The initial dehydrogenation temperature is reduced 50% to 62 °C.•The hydrogen supplying performance could achieve ...as high as 9.3 wt%.•The catalytic activity comes from the synergy of multivalent Ti and the Pt.
Designing highly efficient catalysts is a major challenge for realizing the practical application of high-capacity hydride in the fuel-cell-based hydrogen economy. Herein, platinum-functionalized Ti3C2 material with an accordion-like structure, interlayer, and surface-dispersed nanoparticles was designed and synthesized. The initial dehydrogenation temperature of high-density hydride AlH3 catalyzed by Ti3C2@Pt could be reduced by 50% to 62 °C, comparable to commercial AlH3. Simultaneously, the hydrogen supplying performance and retention ratio could achieve as high as 9.3 wt% and 98% respectively, which is much higher than that of the best catalysts so far reported. It can be attributed to the high activity of the catalyst originates from the multivalent Ti and the Pt, which promotes the transfer of electrons and hydrogen. The material with excellent dehydrogenation performance provides a practical candidate for mobile device applications under the action of high-efficiency catalysts.
Fertilizing controlled-release fertilizer is apt to keep a reasonable concentration of nutrient in soil and increase the efficiency of fertilizer utilization. The production of film-coated ...controlled-release fertilizer using polymer latex is a green process. However, the release period is usually short because the film crosslinking density is low during the fast film formation of the dynamic granule coating. In this study, numerous epoxy groups were grafted onto the nanoparticle surface of single-particle-dispersed silica to prepare particulate crosslinker with abundant crosslinking sites. The epoxy groups on the surface of the particulate crosslinker reacted with the carboxyl groups on the surface of the styrene-acrylate latex particles during film formation, enhancing film crosslinking. With the addition of the particulate crosslinker, the polymer latex was used to coat urea granules in a fluidized bed via spray coating at a low coating content of 4 wt%. The release period of film-coated urea granules with an enhanced crosslinking film reached 40 d, which was five times longer than that in the absence of particulate crosslinker.
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•Particulate crosslinker was fabricated by grafting KH560 on silica sol particles.•Crosslinking of polymer latex film was enhanced by particulate crosslinker.•Release period of enhanced crosslinking film-coated urea granules was prolonged.•Provide a new route for producing controlled-release fertilizer.
