نتایج جستجو برای: نانوذرات ceo2

تعداد نتایج: 10021  

Journal: :journal of ultrafine grained and nanostructured materials 2015
majid farahmandjou mahsa zarinkamar

cerium oxide (ceo2) or ceria has been shown to be an interesting support material for noble metals in catalysts designed for emission control, mainly due to its oxygen storage capacity. ceria nanoparticles were prepared by precipitation method. the precursor materials used in this research were cerium nitrate hexahydrate (as a basic material), potassium carbonate and potassium hydroxide (as pre...

2015
Reza Zamiri Hossein Abbastabar Ahangar Ajay Kaushal Azmi Zakaria Golnoosh Zamiri David Tobaldi J. M. F. Ferreira

A template-free precipitation method was used as a simple and low cost method for preparation of CeO2 nanoparticles. The structure and morphology of the prepared nanoparticle samples were studied in detail using X-ray diffraction, Raman spectroscopy and Scanning Electron Microscopy (SEM) measurements. The whole powder pattern modelling (WPPM) method was applied on XRD data to accurately measure...

2015
Olimpia Gamucci Giuseppe Bardi

Cerium dioxide nanoparticles (CeO2 NPs) are known as scavengers of reactive oxygen species for the coexistence of Ce/ Ce oxidation states. Cell treatments with CeO2 NPs often lead to controversial proinflammatory and anti-inflammatory results. The aim of the study was to investigate the immune events following the administration of ceria nanoparticles to THP-1 monocytes. To address this issue, ...

2015
Caihua Wei Xiaolong Zhang Feifei Lu Yanyan Song Zhanbo Sun

Nanoporous CuO/CeO2 ribbons are successfully prepared through dealloying melt-spun Al80−xCu20Cex (x = 0.5, 1, 2, 3, at%) alloy in a 5 wt% NaOH aqueous solution, followed by calcining in air. The samples are characterized by XRD, SEM, EDS, HRTEM, Raman and gas chromatograph. For the dealloyed melt-spun Al80−xCu20Cex (x = 0.5, 1, 2, 3, at%) alloy, the XRD results indicate that Cu and Cu2O are for...

Cerium oxide (CeO2) or ceria has been shown to be an interesting support material for noble metals in catalysts designed for emission control, mainly due to its oxygen storage capacity. Ceria nanoparticles were prepared by precipitation method. The precursor materials used in this research were cerium nitrate hexahydrate (as a basic material), potassium carbonate and potassium hydroxide (as pre...

2005
B. Šmíd

The catalytic activity for CO oxidation over cerium dioxide (CeO2) and Cu-modified ceria (Cu/CeO2) powders prepared by wetness impregnation method was investigated in flow tube reactor system under atmospheric pressure. Reaction curves of powder samples pre-treated by calcination in mixture of argon and oxygen and by reduction in hydrogen, all at 300 °C were measured. X-ray photoelectron spectr...

The CO preferential oxidation (PrOx) is one of the critical steps in hydrogen production and purification for Polymer Electrolyte Membrane Fuel Cell (PEMFC). This reaction was investigated in the presence of excess hydrogen over Cu/CeO2, Pt/CeO2 and Cu-Pt/CeO2 catalysts. The ceria supports was prepared via precipitation method and Cu-Pt/CeO2 catalyst was synthesized by sequential impregnation o...

2006
O. Pozdnyakova D. Teschner A. Wootsch J. Kröhnert B. Steinhauer H. Sauer L. Toth F. C. Jentoft A. Knop-Gericke Z. Paál R. Schlögl

The aim of the PROX reaction is to reduce the CO content of hydrogen feed to proton exchange membrane fuel cells (PEMFC) by selective oxidation of CO in the presence of excess hydrogen. Both Pt and Pd on ceria are active in CO oxidation (without hydrogen) while Pd is poorly active in the presence of hydrogen. In this paper we aimed at finding the reasons of such behavior, using the same techniq...

2007
Weisheng Lin Isaac Stayton Yue-wern Huang Xiao-Dong Zhou Yinfa Ma

The cytotoxicity of 13 and 22 nm aluminum oxide (Al2O3) nanoparticles was investigated in cultured human bronchoalveolar carcinoma-derived cells (A549) and compared with 20 nm CeO2 and 40 nm TiO2 nanoparticles as positive and negative control, respectively. Exposure to both Al2O3 nanoparticles for 24 h at 10 and 25mgmL 1 doses significantly decreased cell viability compared with control. Howeve...

2014
M. H. Khedr M. I. Nasr K. S. Abdel Halim A. A. Farghali N. K. Soliman

Nanosized CuO-CeO2, CuO-Fe2O3, CuO-CeO2-Al2O3 and CuO-Fe2O3-CeO2-Al2O3 were prepared by co-precipitation and wet impregnation techniques and were used for Catalytic decomposition of acetylene to produce carbon nanotubes (CNTs). Weight gain technique was used to follow up the catalytic reactions. The results revealed that catalyst chemical composition, catalytic temperature, acetylene flow rate ...

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