Cerium Oxide
Mostrando 13-22 de 22 artigos, teses e dissertações.
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13. Síntese, estudo cinético e análise microestrutural do sistema cério-níquel obtido pelo método pechini
The cerium oxide has a high potential for use in removing pollutants after combustion, removal of organic matter in waste water and the fuel-cell technology. The nickel oxide is an attractive material due to its excellent chemical stability and their optical properties, electrical and magnetic. In this work, CeO2-NiO- systems on molars reasons 1:1(I), 1:2(II
Publicado em: 2008
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14. Effect of CeO2 loading on the properties of Ni/CeO2/Al2O3 catalysts on the methane steam and with carbon dioxide reformings / Efeito da adição de CeO2 no catalisador Ni/Al2O3 aplicado durante as reações de reforma a vapor e com dióxido de carbono do metano
Na atualidade, a reforma do metano é de grande interesse industrial para o aproveitamento deste gás na produção de hidrogênio e de gás de síntese. Entre as reações de reforma do metano, destacam-se as reações de reforma a vapor e a reação com dióxido de carbono.O catalisador comumente utilizado nos processos re reforma do metano é Ni/Al2O3. Po
Publicado em: 2008
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15. Estudo do efeito da dopagem da alumina com CÃrio em catalisadores Pt/CeZrO2/Al2O3 na reaÃÃo de oxidaÃÃo parcial do Metano
The transformation of methane into liquid fuels has drawn a lot of attention in the last years due to both economical and environmental concerns. Currently, the main route to obtain synthesis gas from methane is the steam reforming. The major problems associated with this route are the high temperatures and pressures required. Nowadays, the partial oxidation
Publicado em: 2007
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16. Incorporação de enxofre no silicato dicálcico do clínquer de cimento Portland: influência na estabilidade de polimorfos e na reatividade hidráulica / Sulfur incorporation on dicalcium silicate of Portland cement clinker: influence on polymorphic stability and hydraulic reactivity
The present study regards the incorporation of sulfur in dicalcium silicate (Ca2SiO4), a crystalline phase that represents 20 to 40 wt. % of the common Portland cement clinker. In the cement industry this compound is known as C2S (2CaO.SiO2) or belite. It has five polymorphs, and the monoclinic high temperature ?-C2S has the highest reactivity with water. Th
Publicado em: 2007
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17. Effect of surface deposited rare earth oxide gel characteristics on cyclic oxidation behavior of Fe20-Cr alloys
Rare earths have been used to increase high temperature oxidation resistance of many chromium dioxide and alumina forming alloys. These rare earths can be added as elements (or as oxide dispersions) to the alloys or applied as an oxide coating to the alloy surface. The sol-gel technique is considered to be very efficient to apply fine oxide particle coatings
Materials Research. Publicado em: 2006-06
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18. Obtenção de filmes passivantes de molibdato de amonio e nitrato de cerio para ligas de zinco eletrodepositadas / The attainment of passivating films of ammonium molybdate and cerium nitrate for alloys of zinc electrodeposits
The electroplated zinc alloy coatings present better corrosion resistance than pure zinc, but they need a posterior passive treatment aiming the reduction of the formation of white corrosion products. Chromate conversion process is the process that, until now, presents the best results as passive treatment for zinc alloy coatings, although it presents high t
Publicado em: 2005
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19. Catalytic combustion of methane by palladium-supported molecular sieves / Combustão catalitica de metano usando paladio suportado em peneiras moleculares
The partieipation of the natural gas in energy generation has grown significantly in the last years in Brazil as well as in the world. Its use in the combustion generates emission pollutants in lower degrees when compared to other fossils fuels. This is very important in times when the goals of the Kyoto s protocol have to be achieved. In this sense, the Bra
Publicado em: 2005
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20. Synthesis of carbon nanostructures by using thermal plasma torch
Some recent results concerning the synthesis of carbon nanostructures in a thermal plasma generating by a plasma torch are presented. Several tests were carried out in different operational conditions. The plasma was formed with argon and different gas mixtures of argon-acetylene or argon-methane to which some catalyst materials (ferrocene and cerium oxide)
Brazilian Journal of Physics. Publicado em: 2004-12
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21. Caracterização de catalisadores Cu/CeO2/Al2O3 por redução a temperatura programada e atividade para oxidação de CO
The kinetic parameters for the CO oxidation reaction using copper/alumina-modified ceria as catalysts were determined. The catalysts with different concentrations of the metals were prepared using impregnation methods. In addition, the reduction-oxidation behaviour of the catalysts were investigated by temperature-programmed reduction. The activity results s
Química Nova. Publicado em: 2001-02
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22. Estudo das propriedades fisico-quimicas de catalisadores a base de CeO2 e Pd-CeO2 modificados por alcalinos I
The objective of this work was to study the physico-chemical and catalytic properties of ceO2 and Pd-CeO2 systems. Cerium oxides of high (C400) and low (C850) surface area and cerium oxides doped with sodium and barium compounds were used in this study. It was also analysed the influence of residual contaminants such as carbonates and nitrates on the propert
Publicado em: 1995