نتایج جستجو برای: catalyst activity
تعداد نتایج: 1169846 فیلتر نتایج به سال:
Active sites are created on the surface of a Li/MgO catalyst used for the selective oxidation of methane by the gradual loss of carbondioxide from surface carbonate species in the presence of oxygen. Decomposition of the carbonat~ species in the absence of oxygen is detrimental to the activity of the cataIy~t. The active sites'created are not stable but disappear either as a result of reaction ...
We present the activities and selectivities of Pt/Al2O3-based catalysts in the production of hydrogen from methanol through catalytic decomposition. For the decomposition reaction, the Pt and Pd catalysts promoted by ceria exhibit similar activity reaching 100% conversion at 315 C. Promoting with ceria had a positive effect on activity and selectivity. Among all catalysts, the 9% Pt– 10% CeO2/A...
CO2 reforming of methane (CRM) over unpromoted and potassium promoted Ni/Al2O3 catalysts was studied. The catalysts were prepared by impregnation method and characterized by X-ray diffraction (XRD), N2 adsorption (BET), temperature programmed reduction (TPR), temperature programmed oxidation (TPO) and scanning electron microscope (SEM) techniques. The obtained results showed that addition of K2...
In this research, a new magnetic nanocatalyst CuFe2O4@Si-Imid-PMo containing acidic ionic liquid based on imidazolium cation and phosphomolybdic acid anion immobilized on CuFe2O4@SiO2 magnetic nanoparticles was prepared and characterized using FT-IR, EDX, SEM, and VSM techniques. Then, the catalytic activity of CuFe2O4@Si-Imid-PMo was evaluated in the synthesis of 2,4,5-trisubstituted imidazole...
a simple and efficient method for the chemoselective 1,1-diacetate protection of aromatic aldehydes with acetic anhydride by using ni2+ supported on hydroxyapatite-core-shell magnetic γ-fe2o3 nanoparticles (γ-fe2o3@hap-ni2+) under solvent free conditions. this method has several advantages, including high yield, short reaction time, simple work-up and recyclable property of the catalyst. the ca...
Palladium is the best metal catalyst for Suzuki cross coupling reaction for synthesize of unsymmetrical biaryl compounds. But its high cost limits its application in wide scale. Using of nanoscale particles as active catalytic cites is a good approach for reducing needed noble metal. By loading precious nanoparticles on magnetic nanocores as a support, recycling and reusing of catalyst will be ...
The design of a non-precious metal oxygen reduction reaction (ORR) catalyst of high activity and long durability in acidic electrolyte is of great importance for the development and commercialization of low-temperature fuel cells, which remains a great challenge to date. Here, we demonstrate a facile, scalable protocol for the controlled synthesis of CoxC encapsulated in carbon nanotubes as a n...
the interaction of the external donor (propyltrimethoxysilane - ptms) with titanium-magnesium catalysts (tmcs) containing dibutylphthalate (dbp) as internal donor, which were prepared in different ways, was studied by chemical analysis and infrared diffuse reflectance spectroscopy (drifts). the chemical composition of the catalysts after their interaction with heptane solutions of ptms, ptms/al...
Hydrogen spillover over macroscopic distances was demonstrated and exploited in the design of two novel catalytic reactors for 1-butene isomerization. A dual-bed reactor containing separate zones of noble metal and bimetallic catalysts yielded activities up to 2.7 times greater than that of the noble metal alone. The noble metal catalyst contained palladium supported on graphitic carbon. The bi...
Biodiesel production is worthy of continued study and optimization of production procedures due to its environmentally beneficial attributes and its renewable nature. Heterogeneous transesterification is considered to be a green process. The process requires neither catalyst recovery nor aqueous treatment steps and very high yields of methyl esters can be obtained, close to the theoretical valu...
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