نتایج جستجو برای: nano ceria
تعداد نتایج: 52616 فیلتر نتایج به سال:
In this study we probe the electrocatalytic activity of Pt nanoparticles supported on ceria nanoparticles (NPs) and nanorods (NRs) in the ethanol oxidation reaction (EOR) in alkaline media. The goal of this study was to relate morphology, support structure and composition to the EOR catalytic activity by using in situ X-ray absorption fine structure (XAFS) studies. Cyclic voltammetry experiment...
nanocrystalline ceria has been considered as support for carbon monoxide preferentially oxidation. in this study ceria was prepared by precipitation method and the effects of preparation conditions, such as ph of solution (8-10), aging time (1-12 hr), drying temperature (80-120 °c), calcination time (2-6 hr) and temperature (400-600 °c) were investigated on ceria synthesized powders properties....
A series of ceria nanocatalysts have been prepared to study the structure dependency of the CO oxidation reaction. The ceria samples with well-defined nanostructures (nanocubes/Ce-NC and nanorods/Ce-NR) have been prepared using the hydrothermal method. Mesoporous ceria (Ce-MES) and ceria synthesized with solution combustion technique (Ce-SCS) have also been prepared for comparison. The lowest C...
Being endowed with an ability of capturing and releasing oxygen, the ceria surface conventionally assumes the role of catalyzing redox reactions in chemistry. This catalytic effect also makes possible its cytotoxicity toward microorganisms at room temperature. To study this cytotoxicity, we synthesized the doped and undoped ceria particles of 8-9 nm in size using an inexpensive precipitation me...
In recent years, ceria and doped-ceria anisotropic nanocrystals (NC’s) have been produced by a variety of solution-based synthetic routes. The motivation in producing ceria-based NCs with controlled morphology is to develop high surface area catalyst supports with well-defined exposed crystal planes that exhibit optimal catalytic activity. Understanding the growth mechanism of CeO2 NC’s is vita...
A quasi in situ X-ray absorption study demonstrated that the disproportionation of hydrogen peroxide (H2O2) promoted by ceria nanorods was associated with a reversible Ce(3+)/Ce(4+) reaction and structural transformations in ceria. The direction of this reversible reaction was postulated to depend on the H2O2 concentration and the fraction of Ce(3+) species in ceria nanorods.
A significant morphology change from ceria nanoparticles to nanocubes was observed in ceria nanocrystals when CO molecules were introduced into the synthetic system, which is attributed to the surface selective growth driven by strong surface selective adsorption of CO onto the ceria surface.
The effect of the suppport on oxidative dehydrogenation activity for vanadia/ceria systems is examined for the oxidation of methanol to formaldehyde by use of well-defined VO(x)/CeO(2)(111) model catalysts. Temperature-programmed desorption at low vanadia loadings revealed reactivity at much lower temperature (370 K) as compared to pure ceria and vanadia on inert supports such as silica. Densit...
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