Crystalline microporous zeolites are one of the most useful catalysts in industrial processes such as oil refining and organic synthesis owing to their strong catalytic performance, high thermal and hydrothermal stabi...
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Crystalline microporous zeolites are one of the most useful catalysts in industrial processes such as oil refining and organic synthesis owing to their strong catalytic performance, high thermal and hydrothermal stabilities, and well-defined micropores with excellent shape-selectivity in catalysis. However, one disadvantage of these zeolitic catalysts is that their pores are too small to be accessed by bulky reactants, thus hindering their use in the fine chemical and petroleum processing industries. To overcome such drawbacks, we have synthesized hierarchically ordered micro-meso-macroporous solid-acid catalysts via a chemically crystallization process in an improved hydrothermal system. Zeolites, including Silicalite-1, ZSM-5, Beta and TS-1, with hierarchically ordered micro-meso-macroporous structure have been synthesized. It is expected that these hierarchical zeolite materials will exhibit superior catalytic performance owing to the improved mass-transfer properties.
Pt-based nanostructures have attracted tremendous research attention owing to their excellent performance in many applications,such as proton-exchange membrane(PEM) fuel *** Pt-based alloy which not only reduce the co...
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Pt-based nanostructures have attracted tremendous research attention owing to their excellent performance in many applications,such as proton-exchange membrane(PEM) fuel *** Pt-based alloy which not only reduce the content of Pt,but also usually show a superior performance compared with pure Pt *** improve the stability,durability and utilization efficiency of metals,various types of nano-architectures,especially nanoporous structure,have been employed as catalyst *** avoiding the blocking of channels between pores and aggregation of nanoparticles,it's very necessary to synthesize uniform Pt-based bimetallic nanoparticles highly monodispersed in nanostructures for maximizing the activity of a Pt-based ***,we synthesized highly monodispersed PtPd nanoparticles encapsulated in a unique "one particle@one cell" structure by adjusting the viscosity of solvents using mesocellular *** nanocomposites exhibit excellent electrocatalytic activity(over 4 times mass and specific activities than the commercial Pt/C catalyst).Importantly,this nanocatalyst shows no obvious change of structure and only 29.5% loss in electrochemically active surface area after 5000 potential *** synthetic approach is facile and general for the design of practical catalysts,which could combine functionalities in all of the compositions.
Pure K2Ti4O9 whiskers were prepared by KDC(Kneading-Drying-Calcination) method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio(RT/K), calcination temperature(TC) and cooling proces...
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Pure K2Ti4O9 whiskers were prepared by KDC(Kneading-Drying-Calcination) method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio(RT/K), calcination temperature(TC) and cooling process on phase composition and morphology of the whiskers were investigated by TG-DSC(thermo gravimetric-differential scanning calorimeter), XRD(X-ray diffraction), and SEM(scanning electron microscope). Pure K2Ti4O9 potassium titanate whiskers with large length-diameter ratio(r)(over 250) can be obtained at RT/K = 2.9 and TC = 950 ℃.
K2Ti4O9 nanowhiskers were synthesised via stearic acid method by using potassium hydroxide (KOH) and tetrabutyl titanate (Ti(OC4H9)4) as raw materials. The effects of molar ratio of tetrabutyl titanate and KOH (RT/K),...
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The generation of chemical fuels by solar energy conversion is considered to be one of major strategies for solving the global energy and environmental problems in the future. Photocatalytic water splitting for H2 pro...
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The generation of chemical fuels by solar energy conversion is considered to be one of major strategies for solving the global energy and environmental problems in the future. Photocatalytic water splitting for H2 production has become an important and promising method for clean, economical, and renewal production of hydrogen by using solar light since Fujishima and Honda first r eported the photoelectrochemical water splitting on a TiO2 electrode in 1972. Among various semiconductors, titania (TiO2 ) has drawn special
Over the last decade, significant effort has been devoted to the applications of hierarchically structured porous materials owing to their outstanding properties such as high surface area, excellent accessibility to a...
Over the last decade, significant effort has been devoted to the applications of hierarchically structured porous materials owing to their outstanding properties such as high surface area, excellent accessibility to active sites, and enhanced mass transport and diffusion. The hierarchy of porosity, structural, morphological and component levels in these materials is key for their high performance in all kinds of applications. The introduction of hierarchical porosity into materials has led to a significant improvement in the performance of materials. Herein, recent progress in the applications of hierarchically structured porous materials from energy conversion and storage, catalysis, photocatalysis, adsorption, separation, and sensing to biomedicine is reviewed. Their potential future applications are also highlighted. We particularly dwell on the relationship between hierarchically porous structures and properties, with examples of each type of hierarchically structured porous material according to its chemical composition and physical characteristics. The present review aims to open up a new avenue to guide the readers to quickly obtain in-depth knowledge of applications of hierarchically porous materials and to have a good idea about selecting and designing suitable hierarchically porous materials for a specific application. In addition to focusing on the applications of hierarchically porous materials, this comprehensive review could stimulate researchers to synthesize new advanced hierarchically porous solids.
An equiatomic CoCrFeNiMnAl high-entropy alloy was synthesized by mechanical alloying, and alloying behaviors, microstructure and annealing behaviors were investigated. It was found that a solid solution with refined m...
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