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(Jinian Yang, Xuesong Feng, Shibin Nie, Yuxuan Xu, Zhenyu Li, pp. 484–497) Due to the intrinsic drawbacks of relatively high brittleness and poor wear resistance, epoxy products cannot undergo the rubbing actions under dry sliding and hard to be sate when served as engineering parts. Yang et al. propose a promising solution to solve the above problem by introducing low-content flower-like nickel phyllosilicates to yield the cost-effective epoxy nanocomposites with highly res [Detail] ...
Carbon-coated Ni, Co and Ni-Co alloy catalysts were prepared by the carbonization of the metal doped resorcinol-formaldehyde resins synthesized by the one-pot extended Stöber method. It was found that the introduction of Co remarkably reduced the carbon microsphere size. The metallic Ni, Co, and Ni-Co alloy particles (mainly 10–12 nm) were uniformly distributed in carbon microspheres. A charge transfer from Ni to Co appeared in the Ni-Co alloy. Compared with those of metallic Ni and Co, the d-band center of the Ni-Co alloy shifted away from and toward the Fermi level, respectively. In the in-situ aqueous phase hydrodeoxygenation of methyl palmitate with methanol as the hydrogen donor at 330 °C, the decarbonylation/decarboxylation pathway dominated on all catalysts. The Ni-Co@C catalysts gave higher activity than the Ni@C and Co@C catalysts, and the yields of n-pentadecane and n-C6–n-C16 reached 71.6% and 92.6%, respectively. The excellent performance of Ni-Co@C is attributed to the electronic interactions between Ni and Co and the small carbon microspheres. Due to the confinement effect of carbon, the metal particles showed high resistance to sintering under harsh hydrothermal conditions. Catalyst deactivation is due to the carbonaceous deposition, and the regeneration with CO2 recovered the catalyst reactivity.
The catalytic hydrogenation of nitroaromatics is an environmentally friendly technology for aniline production, and it is crucial to develop noble-metal-free catalysts that can achieve chemoselective hydrogenation of nitroaromatics under mild reaction conditions. In this work, zinc-modified Ni-Ti catalysts (NixZnyTi1) were fabricated and applied for the hydrogenation of nitroaromatics hydrogenation. It was found that the introduction of zinc effectively increases the surface Ni density, enhances the electronic effect, and improves the interaction between Ni and TiO2, resulting in smaller Ni particle size, more oxygen vacancies, higher dispersion and greater concentration of Ni on the catalyst surface. Furthermore, the electron-rich Niδ– obtained by electron transfer from Zn and Ti to Ni effectively adsorbs and dissociates hydrogen. The results reveal that NixZnyTi1 (Ni0.5Zn0.5Ti1) shows excellent catalytic performance under mild conditions (70 °C and 6 bar). These findings provide a rational strategy for the development of highly active non-noble-metal hydrogenation catalysts.
Surface functionalization or modification to introduce more oxygen-containing functional groups to biochar is an effective strategy for tuning the physicochemical properties and promoting follow-up applications. In this study, non-thermal plasma was applied for biochar surface carving before being used in contaminant removal and energy storage applications. The results showed that even a low dose of plasma exposure could introduce a high number density of oxygen-functional groups and enhance the hydrophilicity and metal affinity of the pristine biochar. The plasma-treated biochar enabled a faster metal-adsorption rate and a 40% higher maximum adsorption capacity of heavy metal ion Pb2+. Moreover, to add more functionality to biochar surface, biochar with and without plasma pre-treatment was activated by KOH at a temperature of 800 °C. Using the same amount of KOH, the plasma treatment resulted in an activated carbon product with the larger BET surface area and pore volume. The performance of the treated activated carbon as a supercapacitor electrode was also substantially improved by>30%. This study may provide guidelines for enhancing the surface functionality and application performances of biochar using non-thermal-based techniques.
The nanocomposites of flower-like nickel phyllosilicate particles incorporated into epoxy resin were fabricated via an in-situ mixing process. The flower-like nickel phyllosilicate particles were firstly synthesized using a mild self-sacrificial templating method, and the morphology and lamellar structure were examined carefully. Several properties of mechanical, thermal and tribological responses of epoxy nanocomposites were performed. It was demonstrated that adequate flower-like nickel phyllosilicate particles dispersed well in the matrix, and the nanocomposites displayed enhanced tensile strength and elastic modulus but decreased elongation at break as expected. In addition, friction coefficient and wear rate were increased first and then decreased along with the particle content, and showed the lowest values at a mass fraction of 5%. Nevertheless, the incorporated flower-like nickel phyllosilicate particles resulted in the continuously increasing thermal stability of epoxy resin (EP) nanocomposites. This study revealed the giant potential of flower-like particles in preparing high-quality EP nanocomposites.
The electrochemical conversion of CO2-H2O into CO-H2 using renewable energy is a promising technique for clean syngas production. Low-cost electrocatalysts to produce tunable syngas with a potential-independent CO/H2 ratio are highly desired. Herein, a series of N-doped carbon nanotubes encapsulating binary alloy nanoparticles (MxNi-NCNT, M= Fe, Co) were successfully fabricated through the co-pyrolysis of melamine and metal precursors. The MxNi-NCNT samples exhibited bamboo-like nanotubular structures with a large specific surface area and high degree of graphitization. Their electrocatalytic performance for syngas production can be tuned by changing the alloy compositions and modifying the electronic structure of the carbon nanotube through the encapsulated metal nanoparticles. Consequently, syngas with a wide range of CO/H2 ratios, from 0.5:1 to 3.4:1, can be produced on MxNi-NCNT. More importantly, stable CO/H2 ratios of 2:1 and 1.5:1, corresponding to the ratio to produce biofuels by syngas fermentation, could be realized on Co1Ni-NCNT and Co2Ni-NCNT, respectively, over a potential window of –0.8 to –1.2 V versus the reversible hydrogen electrode. Our work provides an approach to develop low-cost and potential-independent electrocatalysts to effectively produce syngas with an adjustable CO/H2 ratio from electrochemical CO2 reduction.
Lithium-sulfur batteries have been regarded as the next-generation rechargeable batteries due to their high theoretical energy density and specific capacity. Nevertheless, the shuttle effect of lithium polysulfides has hindered the development of lithium-sulfur batteries. Herein, a novel zirconium-based metal-organic framework-801 film on carbon cloth was developed as a versatile interlayer for lithium-sulfur batteries. This interlayer has a hierarchical porous structure, suitable for the immobilization of lithium polysulfides and accommodating volume expansion on cycling. Moreover, the MOF-801 material is capable of strongly adsorbing lithium polysulfides and promoting their catalytic conversion, which can be enhanced by the abundant active sites provided by the continuous structure of the MOF-801 films. Based on the above advantages, the lithium-sulfur battery, with the proposed interlayer, delivers an initial discharge capacity of 927 mAh·g–1 at 1 C with an extremely low decay rate of 0.04% over 500 cycles. Additionally, a high area capacity of 4.3 mAh·cm–2 can be achieved under increased S loading.
Solubility has been widely regarded as a fundamental property of small molecule drugs and drug candidates, as it has a profound impact on the crystallization process. Solubility prediction, as an alternative to experiments which can reduce waste and improve crystallization process efficiency, has attracted increasing attention. However, there are still many urgent challenges thus far. Herein we used seven descriptors based on understanding dissolution behavior to establish two solubility prediction models by machine learning algorithms. The solubility data of 120 active pharmaceutical ingredients (APIs) in ethanol were considered in the prediction models, which were constructed by random decision forests and artificial neural network with optimized data structure and model accuracy. Furthermore, a comparison with traditional prediction methods including the modified solubility equation and the quantitative structure-property relationships model was carried out. The highest accuracy shown by the testing set proves that the ML models have the best solubility prediction ability. Multiple linear regression and stepwise regression were used to further investigate the critical factor in determining solubility value. The results revealed that the API properties and the solute-solvent interaction both provide a nonnegligible contribution to the solubility value.
Many scientific efforts have been made to penetrate the blood-brain barrier and target glioblastoma cells, but the outcomes have been limited. More attention should be given to local inhibition of recurrence after glioblastoma resection to meet real medical needs. A biodegradable wafer containing the chemotherapeutics carmustine (1,3-bis(2-chloroethyl)-1-nitrosourea, BCNU) was the only local drug delivery system approved for clinical glioblastoma treatment, but with a prolonged survival time of only two months and frequent side effects. In this study, to improve the sustained release and prolonged therapeutic effect of drugs for inhibiting tumor recurrence after tumor resection, both free BCNU and BCNU- poly (lactic-co-glycolic acid) (the ratio of lactic acid groups to glycolic acid groups is 75/25) nanoparticles were simultaneously loaded into natural extracellular matrix hydrogel from pigskin to prepare BCNU gels. The hydrogel was injected into the resection cavity of a glioblastoma tumor immediately after tumor removal in a fully characterized resection rat model. Free drugs were released instantly to kill the residual tumor cells, while drugs in nanoparticles were continuously released to achieve a continuous and effective inhibition of the residual tumor cells for 30 days. These combined actions effectively restricted tumor growth in rats. Thus, this strategy of local drug implantation and delivery may provide a reliable method to inhibit the recurrence of glioblastoma after tumor resection in vivo.
Semi-batch operated reaction processes are necessary for some competitive reaction systems to achieve a desirable process selectivity and productivity of fine chemical products. Herein the structural and operating parameters of the teethed high shear mixers were adjusted to study the micromixing performance in the semi-batch operated system, using the Villermaux/Dushman reaction system. The results indicate that the rising of the rotor speed and the number of rotor teeth, the decrease of the width of the shear gap and the radial distance between the feed position and the inner wall of stator can enhance the micromixing level and lead to the decrease of the segregation index. Additionally, computational fluid dynamics calculations were carried out to disclose the evolution of the flow pattern and turbulent energy dissipation rate of the semi-batch operated high shear mixer. Furthermore, the correlation was established with a mean relative error of 8.05% and R2 of 0.955 to fit the segregation index and the parameters studied in this work, which can provide valuable guidance on the design and optimization of the semi-batch operated high shear mixers in practical applications.
