نتایج جستجو برای: heterogeneous catalytic

تعداد نتایج: 202404  

Journal: :Nature materials 2008
Weilin Xu Jason S Kong Yun-Ting E Yeh Peng Chen

Nanoparticles are important catalysts for many chemical transformations. However, owing to their structural dispersions, heterogeneous distribution of surface sites and surface restructuring dynamics, nanoparticles are intrinsically heterogeneous and challenging to characterize in ensemble measurements. Using a single-nanoparticle single-turnover approach, we study the redox catalysis of indivi...

Journal: :Journal of the American Chemical Society 2007
Patrick Han Stephanus Axnanda Igor Lyubinetsky D Wayne Goodman

The distance between surface Pd atoms has been shown to control the catalytic formation of vinyl acetate from ethylene and acetic acid by AuPd catalysts. Here, we use the bulk alloy's thermodynamic properties, as well as the surface lattice spacing of a AuPd(100) alloy single-crystal model catalyst to control and optimize the concentration of the active site (Pd atom pairs at a specific Pd-Pd d...

Journal: :Catalysts 2022

Versatile homogeneous and heterogeneous catalysts that convert carbohydrates to 2,5-diformylfuran (DFF) are essential for the development of sustainable processes producing high-value chemicals from biomass-derived carbohydrates. An efficient catalytic system consisting Br−, disulfide, dimethylsulfoxide (DMSO) promoted selective synthesis DFF in modest-to-good yields various carbohydrates, such...

Journal: :organic chemistry research 0
habib ollah foroughi department of scince, islamic azad university, fasa branch ali khalafi-nezhad department of chemistry, shiraz university, shiraz,71454, i.r.iran

the silica boron sulfuric acid nanoparticles (sbsans) as an efficient heterogeneous solid acid catalyst with both brønsted and lewis acidic sites catalyzed the preparation of bis-4-hydroxycoumarin derivatives using reaction of aldehydes and 4-hydroxycoumarin under mild and solvent-free condition at room temperature. this new and efficient methodology has advantages in comparison with currently ...

2017
John G. Verkade

Homogeneous transition metal complex catalysts for organic industrial processes are converted to catalysts which are heterogeneous with respect to the reactants, and which have substantially equal catalytic activity to the homogeneous catalysts. This is done by reacting a normally homogeneous transition metal complex catalyst with a metal bridging ligand which substantially duplicates the ligan...

2003
T. A. Peters J. Fontalvo

Pervaporation membrane reactors are ideal candidates to enhance conversion in reversible reactions generating water as a by-product. This equilibrium displacement can be enhanced through close integration of reaction and separation by way of catalytic membranes. In this research, catalytic hollow fibre pervaporation membranes for the close integration of reaction and separation will be develope...

Journal: :iranian journal of catalysis 2015
najme kalvari janaki razieh fazaeli hamid aliyan

a series of fe3o4 supported on mesoporous fdu-12 silica systems were prepared by the hydrothermal conditions. the surface properties of the functionalized catalyst were analyzed by a series of characterization techniques like ftir, xrd, n2 adsorption–desorption and tem. xrd and adsorption–desorption analysis shows that the mesostructure of fdu silica remains intact after fe3o4 modifications, wh...

Journal: :journal of particle science & technology 2015
mohammad pakmehr abolghasem nourmohammadi majid ghashang ali saffar teluri

in recent years, the effects of heterogeneous catalysts for the oxidation of organic and inorganic pollutants in industrial wastewaters are spread. traditionally, these reactions are usually carried out using suspensions of photo-catalysts such as tio2. a chemical method including ticl4, al(no3)3, ethanol amine, ethyl acetoacetate and aqueous ammonia were used for the fabrication of tio2-al2o3 ...

Journal: :Molecules 2015
Jiaqing Wang Hongwei Gu

In the rapidly developing areas of nanotechnology, nano-scale materials as heterogeneous catalysts in the synthesis of organic molecules have gotten more and more attention. In this review, we will summarize the synthesis of several new types of noble metal nanostructures (FePt@Cu nanowires, Pt@Fe₂O₃ nanowires and bimetallic Pt@Ir nanocomplexes; Pt-Au heterostructures, Au-Pt bimetallic nanocomp...

Journal: :ChemSusChem 2017
Qi Sun Yingyin Jin Briana Aguila Xiangju Meng Shengqian Ma Feng-Shou Xiao

Direct use of atmospheric CO2 as a C1 source to synthesize high-value chemicals through environmentally benign processes is of great interest, yet challenging. Porous heterogeneous catalysts that are capable of simultaneously capturing and converting CO2 are promising candidates for such applications. Herein, a family of organic ionic polymers with nanoporous structure, large surface area, stro...

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