Dynamic structural evolution of iron catalysts involving competitive oxidation and carburization during CO hydrogenation.

Identifying the dynamic structure of heterogeneous catalysts is crucial for the rational design of new ones. In this contribution, the structural evolution of Fe(0) catalysts during CO hydrogenation to hydrocarbons has been investigated by using several (quasi) in situ techniques. Upon initial reduction, Fe species are carburized to FeC and then to FeC.

A Facile Strategy to Prepare Shaped ZSM-5 Catalysts with Enhanced Para-Xylene Selectivity and Stability for Toluene Methylation: The Effect of In Situ Modification by Attapulgite.

A general strategy for preparing shaped toluene methylation catalysts with enhanced para-selectivity and stability is developed by extruding ZSM-5 zeolite with attapulgite as a binder. The novel attapulgite/ZSM-5 extrudate exhibited significantly higher para-selectivity and stability in comparison to the conventional alumina-bound ZSM-5 extrudate. The catalyst samples have been characterized by in situ X-ray diffraction, scanning electron microscope (SEM), NH temperature programmed desorption (TPD), thermogravimetric analysis (TGA) as well as n-hexane/cyclohexane physical adsorption.

Effects of mechanical and chemical control on invasive in the Yellow River Delta, China.

is one of the most noxious invasive plants in China and many other regions. Exploring environmentally friendly, economic and effective techniques for controlling is of great significance for the management of coastal wetlands. In the present study, different approaches, including mowing and waterlogging, mowing and tilling and herbicide application, were used to control .

Statistical study of ductility-dip cracking induced plastic deformation in polycrystalline laser 3D printed Ni-based superalloy.

Ductility-dip cracking in Ni-based superalloy, resulting from heat treatment, is known to cause disastrous failure, but its mechanism is still not completely clear. A statistical study of the cracking behavior as a function of crystal orientation in a laser 3D-printed DL125L Ni-based superalloy polycrystal is investigated here using the synchrotron X-ray microdiffraction. The dislocation slip system in each of the forty crystal grains adjacent to the 300 μm long crack has been analyzed through Laue diffraction peak shapes.

Hollow Alveolus-Like Nanovesicle Assembly with Metal-Encapsulated Hollow Zeolite Nanocrystals.

Inspired by the vesicular structure of alveolus which has a porous nanovesicle structure facilitating the transport of oxygen and carbon dioxide, we designed a hollow nanovesicle assembly with metal-encapsulated hollow zeolite that would enhance diffusion of reactants/products and inhibit sintering and leaching of active metals. This zeolitic nanovesicle has been successfully synthesized by a strategy which involves a one-pot hydrothermal synthesis of hollow assembly of metal-containing solid zeolite crystals without a structural template and a selective desilication-recrystallization accompanied by leaching-hydrolysis to convert the metal-containing solid crystals into metal-encapsulated hollow crystals. We demonstrate the strategy in synthesizing a hollow nanovesicle assembly of Fe2O3-encapsulated hollow crystals of ZSM-5 zeolite.

Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys.

Synchrotron-based Laue microdiffraction has been widely applied to characterize the local crystal structure, orientation, and defects of inhomogeneous polycrystalline solids by raster scanning them under a micro/nano focused polychromatic X-ray probe. In a typical experiment, a large number of Laue diffraction patterns are collected, requiring novel data reduction and analysis approaches, especially for researchers who do not have access to fast parallel computing capabilities. In this article, a novel approach is developed by plotting the distributions of the average recorded intensity and the average filtered intensity of the Laue patterns.

A synchrotron study of microstructure gradient in laser additively formed epitaxial Ni-based superalloy.

Laser additive forming is considered to be one of the promising techniques to repair single crystal Ni-based superalloy parts to extend their life and reduce the cost. Preservation of the single crystalline nature and prevention of thermal mechanical failure are two of the most essential issues for the application of this technique. Here we employ synchrotron X-ray microdiffraction to evaluate the quality in terms of crystal orientation and defect distribution of a Ni-based superalloy DZ125L directly formed by a laser additive process rooted from a single crystalline substrate of the same material.

Size-controlled silver nanoparticles stabilized on thiol-functionalized MIL-53(Al) frameworks.

A postsynthetic modification method was used to prepare thiol-functionalized metal-organic frameworks (MOFs) by the amidation of mercaptoacetic acid with the amine group, which is present in the frameworks of NH2-MIL-53(Al). By doing this, the thiol group has been successfully grafted on the MOF, which perfectly combined the highly developed pore structures of the MOF with the strong coordination ability of the thiol group. The resulting thiol-functionalized MIL-53(Al) showed a significantly high adsorption capacity for heavy metal ions like Ag(+) (182.

Synthesis of yolk-shell HPW@Hollow silicalite-1 for esterification reaction.

HPW@Hollow S-1, a novel solid catalyst which can be reused in the synthesis of ethyl acetate, was successfully prepared by the ship-in-bottle approach. The catalyst simultaneously shows high activity that resembles homogeneous catalysts, and outstanding stability like that of heterogeneous catalysts.

Size- and morphology-controlled NH2-MIL-53(Al) prepared in DMF-water mixed solvents.

We present here a simple solvothermal method to fabricate metal-organic framework NH2-MIL-53(Al) crystals with controllable size and morphology just by altering the ratio of water in the DMF-water mixed solvent system without the addition of any surfactants or capping agents. With increasing the volume ratio of water in the mixed solvents, a series of NH2-MIL-53(Al) crystals with different sizes and morphologies were synthesized. The average size of the smallest crystal is 76 ± 20 nm, which provides us a simple and environmentally friendly way to prepare nanoscale MOFs.

Efficient synthesis and sulfonation of ordered mesoporous carbon materials.

Ordered mesoporous carbons (OMCs) with hexagonal structure were efficiently synthesized via cooperative self-assembly of phenol/formaldehyde resol and surfactant F127 under acidic aqueous conditions. Induced by HCl, a gel phase mainly containing phenol/formaldehyde resol and F127 was obtained within several hours. X-ray diffraction (XRD), transmission electron microscope (TEM) and nitrogen adsorption isotherms indicated that the synthesized samples possess 2-D hexagonal mesostructure.