نتایج جستجو برای: catalyst characterization
تعداد نتایج: 415808 فیلتر نتایج به سال:
Graphene supported Pt nanostructures have great potential to be used as catalysts in electrochemical energy conversion and storage technologies; however the simultaneous control of Pt morphology and dispersion, along with ideally tailoring the physical properties of the catalyst support properties has proven very challenging. Using sulfur doped graphene (SG) as a support material, the heterogen...
Although Fischer-Tropsch (F-T) technology has been known for more than 80 years, the information on the fundamentals of the catalytic chemistry is limited, hindering improvements in process development. With respect to the reaction mechanism, most publications generally consider the same limited number of reaction pathways but reach different, often mutually exclusive, conclusions. Specifically...
The liquid phase esterification of phenyl acetic acid with p-cresol over different metal cation exchanged montmorillonite nanoclays yields p-cresyl phenyl acetate. Different metal cation exchanged montmorillonite nanoclays (M n+ = Al3+, Zn2+, Mn2+, Fe3+, Cu2+) were prepared and the catalytic activity was studied. The esterification reaction was conducted by varying molar ratio of the reactants,...
The production of aromatic hydrocarbons from cellulose by zeolite-catalyzed fast pyrolysis involves a complex reaction network sensitive to the zeolite structure, crystallinity, elemental composition, porosity, and acidity. The interplay of these parameters under the reaction conditions represents a major roadblock that has hampered significant improvement in catalyst design for over a decade. ...
This paper reports the preparation and characterization of the coupling of aryl halides with arylboronic acids using a new nanomaterial catalyst Ni(5%): ZnS synthesized in the aqueous phase. The X-ray diffraction (XRD) analysis shows the formation of the cubic zinc blende phase, with a particle size of about 3 nm confirmed by high resolution transmission electron microscopy with a high catalyti...
Exceptionally high surface area and ordered nanopores of a metal-organic framework (MOF) are exploited to encapsulate and homogeneously disperse a considerable amount of phosphotungstic acid (PTA). When combined with platinum nanoparticles positioned on the external surface of the MOF, the construct shows a high catalytic activity for hydroisomerization of n-hexane, a reaction requiring hydroge...
Layer-structured group III chalcogenides have highly anisotropic properties and are attractive materials for stable photocathodes and battery electrodes. We report the controlled synthesis and characterization of layer-structured GaSe nanowires via a catalyst-assisted vapor-liquid-solid (VLS) growth mechanism during GaSe powder evaporation. GaSe nanowires consist of Se-Ga-Ga-Se layers stacked t...
Conversion of vegetable oils and animal fats composed predominantly of triglycerides using pyrolysis type reactions represents a promising option for the production of renewable fuels and chemicals. The purpose of this article was to collect and review literature on the thermo-chemical conversion of triglyceride based materials. The literature was divided and discussed as (1) direct thermal cra...
The heptazine-based polymer melon (also known as graphitic carbon nitride, g-C3N4) is a promising photocatalyst for hydrogen evolution. Nonetheless, attempts to improve its inherently low activity are rarely based on rational approaches because of a lack of fundamental understanding of its mechanistic operation. Here we employ molecular heptazine-based model catalysts to identify the cyanamide ...
This paper argues that innovation can be best understood as an information process which is then concretized as a product that meets demand. Two very different firms, Canon Inc. and Apple Computer Inc., are used as case study illustrations. Innovation does not proceed through logical deduction, but rather is furthered by the use of metaphors and analogies. The bureaucratic and staid structures ...
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