Design and fabrication of novel optimized electrode materials are important for the development of new batteries for energy storage applications. Herein, we report on a hierarchical bulk electrode material with a tail...
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Design and fabrication of novel optimized electrode materials are important for the development of new batteries for energy storage applications. Herein, we report on a hierarchical bulk electrode material with a tailored nanostructure that which consists of three components: a NH 4 V 4 O 10 nanowire as an active skeleton, an intermediate polymer layer (polypyrrole, PPy), and a metal oxide layer (MnO 2 ) as the outside shell. The NH 4 V 4 O 10 -PPy-MnO 2 nanowires exhibit present higher capacitance than that of the simple NH 4 V 4 O 10 -PPy [email protected] or NH 4 V 4 O 10 nanowires. The structure of double shells of combined PPy and MnO 2 is a key factor in enhancing their electrochemical performance including high specific capacitance and excellent cycling stability. Our V-based [email protected] @shell structure can serve as freestanding, compressible electrodes for various energy devices.
Adopting a ceramic/polymer multilayer structure design to simulate the structure of nacre is usually believed to be an effective way to increase the toughness of ceramic composites at the expense of the material’s be...
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Adopting a ceramic/polymer multilayer structure design to simulate the structure of nacre is usually believed to be an effective way to increase the toughness of ceramic composites at the expense of the material’s bending strength. However, in this study, we found that both the bending strength and the toughness could be improved simultaneously when using a certain Al2O3/Kevlar multilayer composite design compared to pure alumina samples with the same dimensions. The fracture behaviour of the Al2O3/Kevlar multilayer composite was studied to find a reason for this improvement. The results showed that the complex and asymmetrical stresses occurring in the Kevlar-reinforced layers were the main reason for the differences in fracture behaviour. We expect our results to open up new ways for the design of future high performance ceramic composites.
High quality nano-sized zirconium carbide (ZrC) powders were successfully fabricated via a developed chemical active dilution self-propagating high-temperature synthesis (SHS) method assisted by ball milling pretr...
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High quality nano-sized zirconium carbide (ZrC) powders were successfully fabricated via a developed chemical active dilution self-propagating high-temperature synthesis (SHS) method assisted by ball milling pretreatment process using traditional cheap zirconium dioxide powder (ZrO2), magnesium powder (Mg) and sucrose (C12H22Oll) as raw materials. FSEM, TEM, HRTEM, SAED, XRD, FTIR and Raman, ICP- AES, laser particle size analyzer, oxygen and nitrogen analyzer, carbon/sulfur determinator and TG-DSC were employed for the characterization of the morphology, structure, chemical composition and thermal stability of the as-synthesized ZrC samples. The as-synthesized samples demonstrated high purity, low oxygen content and evenly distributed ZrC nano-powders with an average particle size of 50nm. In addition, the effects of endothermic rate and the possible chemical reaction mechanism were also discussed.
An improved multi-step sintering process was used to in-situ prepare TiB2-TiB-Ti FGMs. According to the sintering temperatures, the functionally graded materials (FGMs) were divided into three sections. After sinter...
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An improved multi-step sintering process was used to in-situ prepare TiB2-TiB-Ti FGMs. According to the sintering temperatures, the functionally graded materials (FGMs) were divided into three sections. After sintering at a proper temperature, the three sections were sintered together in turn. The experimental results showed that there were no obvious pores and cracks in the whole TiB2-TiB-Ti FGMs, and no delamination was found in the impacting test with good performance features, which indicated that there were no interface effects in FGMs during penetration, so that the TiB2-TiB-Ti FGMs were an ideal FGM.
The rapid synthesis of Kagomé net layer pillared metal organic frameworks(MOFs) structure at room temperature was developed. Although this MOF series [M(bdc)(dabco)] varies in metal center(M= Co, Ni, Zn), the str...
The rapid synthesis of Kagomé net layer pillared metal organic frameworks(MOFs) structure at room temperature was developed. Although this MOF series [M(bdc)(dabco)] varies in metal center(M= Co, Ni, Zn), the structure remains [the MOF is denoted as MBD;M = metal(Co, Ni, Zn);B = bdc(1,4-bicarboxylic acid);D = dabco(1,4-diazabicyclo[2.2.2]octane)]. The Kagomé net pillared structures are determined using comparable XRD patterns and confirmed by SEM. N adsorption isotherms at 77 K are used to evaluate their surface area and porosity properties. Furthermore, the gas uptake analyses(CO, CH and N) were measured at different temperatures and pressure up to 1 bar. Additionally, the heats of adsorption behavior of CO are given by fitting the isotherms with Dual-site Langmuir equations. Finally, the CO/CH and CO/N selectivities are determined by Ideal Adsorbed Solution Theory(IAST) to evaluate the gas separation properties of these materials.
The pyrolysis behavior of polycarbosilane (PCS) and chemical reaction mechanism during the pyrolysis process were studied by thermogravimetric-mass spectrometry (TG-MS) combined with X-ray diffraction and infrared...
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The pyrolysis behavior of polycarbosilane (PCS) and chemical reaction mechanism during the pyrolysis process were studied by thermogravimetric-mass spectrometry (TG-MS) combined with X-ray diffraction and infrared spectroscopic analysis methods. The experimental results indicate that the main gas phase products generated during pyrolysis of PCS in nitrogen atmosphere include H2, -CH3 and CH4. The heating rate has a large effect on the pyrolysis process of PCS, the lower heating rate releases more small molecule gases and gets bigger rate of pyrolysis mass loss, demonstrating that the lower heating rate is beneficial to fully pyrolysis of PCS and obtain ceramics products with better microstructure.
Transitional metals are widely used as co‐catalysts boosting photocatalytic H 2 production. However, metal‐based co‐catalysts suffer from high cost, limited abundance and detrimental environment impact. To date, me...
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Transitional metals are widely used as co‐catalysts boosting photocatalytic H 2 production. However, metal‐based co‐catalysts suffer from high cost, limited abundance and detrimental environment impact. To date, metal‐free co‐catalyst is rarely reported. Here we for the first time utilized density functional calculations to guide the application of phosphorene as a high‐efficiency metal‐free co‐catalyst for CdS, Zn 0.8 Cd 0.2 S or ZnS. Particularly, phosphorene modified CdS shows a high apparent quantum yield of 34.7 % at 420 nm. This outstanding activity arises from the strong electronic coupling between phosphorene and CdS, as well as the favorable band structure, high charge mobility and massive active sites of phosphorene, supported by computations and advanced characterizations, for example, synchrotron‐based X‐ray absorption near edge spectroscopy. This work brings new opportunities to prepare highly‐active, cheap and green photocatalysts.
It is a pleasure to dedicate this special issue of Chinese Journal of Catalysis(CJC)to *** ***,Choh-Ming Li Professor of Chemistry at The Chinese University of Hong *** is to celebrate the 20th anniversary of his re...
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It is a pleasure to dedicate this special issue of Chinese Journal of Catalysis(CJC)to *** ***,Choh-Ming Li Professor of Chemistry at The Chinese University of Hong *** is to celebrate the 20th anniversary of his return to Hong Kong and leading photocatalytic research there.
Fluoridated composite Hydroxyapatite biomaterial was prepared by sintering the hydroxyapatite Ca10(PO4)6. (OH)2[HA]powder with addition of titanium fluoride 30 wt. % -TiF3 and mixture of iron oxide and aluminum oxide ...
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