Platinum Catalyst
Mostrando 13-24 de 32 artigos, teses e dissertações.
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13. Efeito da concentração de irídio sobre as propriedades de catalisadores do tipo Pt-Ge-Ir/Al2O3. / Effect of concentration of iridium on the properties of type catalysts Pt-Ge-Ir/Al2O3.
The effect of iridium content on the activity, selectivity and stability of platinum, germanium and iridium supported in alumina catalysts for oil naphta catalytic reforming was studied in this work. Samples were prepared by the impregnation of the metallic salts (hexachloroplatinic acid, hexachoroiridic acid and germanium chloride) over g-alumina in order t
Publicado em: 2008
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14. 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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15. Dinâmica complexa no sistema bromato/hipofosfito/acetona/manganês e ferroína
New chemical systems have been recently designed for the study of complex phenomena such as oscillatory dynamics in the temporal domain and spatiotemporal pattern formation. Systems derived from oscillators based on the chemistry of bromate are the most extensively studied, with the celebrated Belousov-Zhabotinsky (BZ) reaction being the most popular example
Química Nova. Publicado em: 2007
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16. "ZrO2/g-Al2O3-supported platinum catalysts for the steam reforming of ethanol" / "Catalisadores de platina suportados em ZrO2/g-Al2O3 para a reação de reforma a vapor de etanol"
In this work catalysts of platinum supported on g-alumina (g-Al2O3), oxide of zirconium (ZrO2) and mixed oxide of zirconium and g-alumina had been prepared and characterized. The bi-component supports containing ( 15%) ZrO2/g-Al2O3 had been prepared by two different methods : in the first, an acid suspension of comercial oxide of zirconium was used and in th
Publicado em: 2006
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17. Atividade eletrocatalítica de pós-ultrafinos de Pt(1-y) SnyOz preparados pelo processo Pechini para oxidação de etanol / Eletroactivity of ultrafine powders of Pt (1-y) SnyOz prepared by the Pechini process for oxidation of etanol
In this work, a method for the preparation of eletrocatalysts containing platinum and tin supported on carbon was developed aiming at the ethanol oxidation. This method uses the thermal decomposition of polymeric precursors, known as the Pechini method, for the production of powders with particle size lying in the range of nanometers. Several catalysts were
Publicado em: 2006
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18. Synthesis and characterization of PtRu/C catalysts obtained by colloidal and deposition methods for fuel cell applications
The purpose of this investigation was to compare catalysts produced by the Bönnemann - colloidal method (PtRu (B1) and PtRu (B2)), and those produced by the spontaneous deposition method (PtRu (SD)). The catalysts produced by both methods had good electrochemical behavior for methanol oxidation for proton exchange membrane fuel cell applications. The struct
Materials Research. Publicado em: 2005-06
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19. Estudo da Adição do Promotor Cu aos Catalisadores Pt/Al2O3 e Pt/Nb2O5 para a Oxidação Seletiva de CO / Study of the Addition of Cu Promoter to the Pt/Al2O3 and Pt/Nb2O5 catalysts for the Selective Oxidation of CO
The fuel cells are an alternative to generate energy without polluting the environment. They produce electric energy through the reaction of hydrogen with the oxygen from air. The product of the reaction is water. It is an interesting form of generation energy because its a clean technology. The hydrogen used as combustible for the fuel cells is proceeding f
Publicado em: 2005
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20. "Dependence of the selectivity of the methanol and ethanol electrooxidation reaction on Pt/C and PtRh/C nanoparticles" / "Dependência da seletividade da reação de eletro-oxidação de metanol e etanol sobre nanopartículas de Pt/C e PtRh/C"
The methanol and ethanol electrooxidation is a subject of intense studies in electrocatalysis. The aim of such attention concerning this alcohol electrooxidation activity is due to development of new energy converter systems more efficient and less pollutant. The electrocatalysis research has been also directed to nanoparticle systems. Metallic particles in
Publicado em: 2005
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21. Métodos de preparação de nanopartículas metálicas suportadas em carbono de alta área superficial, como eletrocatalisadores em células a combustível com membrana trocadora de prótons
Fuel cells are attracting much interest as efficient and clean energy conversion devices. The main components of low temperature fuel cells are the electrocatalysts used to promote the anodic and cathodic reactions, which are based on platinum and platinum alloys. These electrocatalysts are normally prepared in the form of metal nanoparticles supported on a
Química Nova. Publicado em: 2004-08
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22. A Interação substrato-modificador e sua importância para a hidrogenação enantiosseletiva de alfa-cetoésteres
The heterogeneous asymmetric catalysis plays an important and crucial role in many chemical processes and has therefore become a growing and interesting field. The enantioselective hydrogenation of α-ketoesters is one of the best known examples of such process. Methyl pyruvate, which can be converted to (R)- and (S)-methyl lactate with an enantioselecti
Publicado em: 2004
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23. Recuperação de metais de catalisadores mássicos e monometálicos
This work presents a study on the dissolution of some commercial monometallic and non-supported deactivated catalysts in HF + H2O2 mixtures (and, eventually, other media) under mild experimental conditions, after a previous oxidation step. The samples were neither crushed nor grinded. The best experimental conditions were dependent on the nature of the suppo
Química Nova. Publicado em: 2003-12
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24. Avaliação do desempenho de catalisadores do tipo Pt-Re-Sn/Al2O3 na reforma de n-octano.
Pt-Re-Sn/Al2O3-Cl catalysts were evaluated in the n-octane reforming to produce aromatics specially xylenes and were compared with the correspondent monometallic(Pt/Al2O3) and bimetallic (Pt-Re and Pt-Sn/Al2O3) ones. The samples were prepared by coimpregnation and successive impregnations of alumina, with the solutions of the metallic precursors. The solids
Publicado em: 2003