نتایج جستجو برای: various catalysts
تعداد نتایج: 797949 فیلتر نتایج به سال:
Pt and PtSn intermetallic nanoparticle (NP) catalysts were grown directly on various reduced graphene oxide (rGO) supports and were characterized by a combination of X-ray photoelectron spectroscopic (XPS), Raman microscopy, transmission electron microscopy (TEM), and powder X-ray diffraction (XRD) studies. Electrochemical CO stripping and rotating disk electrochemical (RDE) experiments showed ...
ethylene polymerization was carried out using phillips chromium catalyst based on silica supports such as silicaaerogel, sio2 (grace 643), and titanium modified sio2 (g 643), and the results were compared with othercatalysts based on sio2 (aldrich), sba-15(hex), sba-15(sp) and mcm-41. a combination of tga, dsc, xrd,nitrogen adsorption, sem, icp, ftir and other analyses were used to characterize...
catalysts with the formula of laco(1+x)o(3+δ), where 0 ≤ x ≤ 1, were studied for oxidation of co and c2h6 in a synthetic exhaust gas, comprising 6.0 % co and 0.2 % c2h6 in ar. ethane was selected as a model for hydrocarbons in the exhaust gas. the performance of catalysts is correlated to their properties, particularly their redox in oxidizing and reducing atmospheres. xrd patterns show perovsk...
the chemistry of 2-oxo-1,2,3,4-tetrahydropyrimidines began to develop toward the end of 1893 year, when the first representatives of this class compounds were reported by p. biginelli. despite prior reports of several really effective catalytic and non-catalytic approaches towards biginelli-type products, an overwhelming number of new catalysts for the biginelli reaction have been recently publ...
Photochemical treatment is increasingly being applied to remedy environmental problems. TiO2-derived catalysts are efficiently and widely used in photodegradation applications. The efficiency of various photochemical treatments, namely, the use of UV irradiation without catalyst or with TiO2/graphene-TiO2 photodegradation methods was determined by comparing the photodegadation of two main types...
Multiwalled carbon nanotubes grafted with various amino groups show high activity and stability when used as basic catalysts for the transesterification of triglycerides.
Photoelectrochemical cells that efficiently split water into oxygen and hydrogen, "the fuel of the future", need to combine robust water oxidation catalysts at the anode (2H(2)O --> O(2) + 4H(+) + 4e(-)) with hydrogen reduction catalysts at the cathode (2H(+) + 2e(-)--> H(2)). Both sets of catalysts will, ideally, operate at low overpotentials and employ light-driven or light-assisted processes...
The reduction of automotive exhaust emissions has been one of the hottest topics in catalysis community since 1970s. Thanks to the development of three-way catalysts, main auto-exhaust pollutants, such as carbon monoxide, nitrogen oxides and unburned hydrocarbons, can be removed simultaneously. Nowadays, diesel engines and lean-burn engines become more and more popular due to their high fuel-ef...
Introduction Approaching 100% selectivity in heterogeneous catalytic reactions is an ultimate objective of catalyst discovery and is critical for the design of efficient, environmentally friendly processes. This work focuses on an example where shape controlled synthesis of silver nano-particles has been utilized along with Density Functional Theory (DFT) calculations to design heterogeneous si...
Wells–Dawson tungsten heteropolyacid (H6P2W18O62) has been applied as an effective heterogeneous catalyst for one-pot synthesis of spiro[4H-pyran-3,3’-oxindoles] via reaction of various isatins, malonitrile and 1,3-dicarbonyl compound in water. The corresponding products were obtained in high yields. The catalysts were easily recycled and reused without loss of their catalytic activity.
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