@MastersThesis{Nader:1997:HiBeSo,
               author = "Nader, Roger Lu{\'{\i}}s",
                title = "Hidrogena{\c{c}}{\~a}o de benzeno sobre catalisadores Ir/Al203 E 
                         Ir-Au/Al203",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "1997",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "1997-04-02",
             keywords = "x.",
             abstract = "Catalisadores Ir/y Al_2O_3 e Ir-Au/yAl_2O_3, com teores de ouro 
                         variando de o at{\'e} 75% ( p/a ), foram preparados atrav{\'e}s 
                         do m{\'e}todo de impregna{\c{c}}{\~a}o incipiente. Os 
                         catalisadores bimet{\'a}licos foram feitos por 
                         coimpregna{\c{c}}{\~a}o das solu{\c{c}}{\~o}es precursoras. Os 
                         catalisadores bimet{\'a}licos foram preparados com teores de 15, 
                         25, 50 e 75% de Au(p/a) da fase met{\'a}lica. O teor total de 
                         metal ficou limitado a 8% em massa. Os resultados de 
                         quimissor{\c{c}}{\~a}o- indicaram que o ouro n{\~a}o afeta a 
                         capacidade de adsor{\c{c}}{\~a}o de 112 sobre ir{\'{\i}}dio. 
                         Os valores de jip e da dispers{\~a}o das part{\'{\i}}culas de 
                         iridio se mostraram semelhantes para todos os catalisadores 
                         at{\'e} o teor de 50% de Au, com d_p= 1,4nm e D_% ~= 67%. O 
                         catalisador com 75% de Au na fase met{\'a}lica apresentou uma 
                         queda no valor de d_p para 1,0mn, e um aumento da dispers{\~a}o 
                         para 88,9%. Os resultados do teste catal{\'{\i}}tico 
                         (rea{\c{c}}{\~a}o de hidrogena{\c{c}}{\~a}o do benzeno), 
                         mostraram que velocidade inicial de rea{\c{c}}{\~a}o cai 
                         proporcionalmente {\`a} diminui{\c{c}}{\~a}o do teor de 
                         iriclio, e os valores da taxa de giro se mant{\'e}m constantes em 
                         torno de T.G_0 at 0,05 s^-1 para os catalisadores com teor de Au 
                         at{\'e} 50%. Entretanto, para o catalisador 75%Au , houve 
                         acentuada queda no valor de V_0, n{\~a}o proporcional {\`a} 
                         diminui{\c{c}}{\~a}o do teor de Ir. A taxa de giro inicial 
                         apresentou um valor de 0,028s^-1 , bastante inferior {\`a}quele 
                         apresentado pelos catalisadores com carregamento de Au menor ou 
                         inexistente. Este comportamento -an{\^o}malo foi 
                         atribu{\'{\i}}do a duas poss{\'{\i}}veis causas: 
                         intera{\c{c}}{\~a}o metal-suporte ou recobrimento do 
                         ir{\'{\i}}dio superficial por part{\'{\i}}culas de Au. 
                         N{\~a}o foi verificada tamb{\'e}m a forma{\c{c}}{\~a}o de liga 
                         Ir-Au, o que pode estar ligado a grande diferen{\c{c}}a de 
                         temperaturas de fus{\~a}o apresentadas pelos dois metais, com 
                         consequente diferen{\c{c}}a de mobilidade superficial dos metais 
                         na temperatura de redu{\c{c}}{\~a}o. Ir1yAl203 and Ir-AukyAl203 
                         catalysts with gold content ranges from O to 75% at. perc. ) were 
                         prepared by the incipient wetness impregnation meffiod. The 
                         bimetallic catalysts were prepared by coimpregnation of the 
                         precursors solutions. The bimetallic catalysts were prepared with 
                         gold content of 15, 25, 50 and 75% ( {\'a}. perc. ) on the 
                         metallic phase. Th e global metallic content was limited at 8% of 
                         mass. The quimissorption results indicated that gold does not 
                         affect the adsorption capacity of the H2 on iridium. Dispersion 
                         and dp values of the iridium particles showed similars to ali 
                         catalysts in the range of O to 50%, with dp = 1,4nm and D(%) -67%. 
                         The catalyst with 75% of gold m the metallic phase presented a 
                         decrease in the -c-ip value to 1,0nm, and a dispersion increase to 
                         88,9%. The results of catalitic test ( benzene- hydrogenation 
                         reaction ), showed that the initial reaction wlocity decay 
                         proportional to iridium content decrease, and the T.G0 values keep 
                         constants near T.G 0 0,05 s-1 to catalysts with gold content in 
                         the range of O to 50%. However, the 75% Au catalyst presented a 
                         not proportional decay of vo with the iridium gold content 
                         decrease. T.G 0 presented a value of 0,028 s -1 , below to that 
                         presented by the catalysts with less gold content. This anomalous 
                         behavior was attributed to two possibles causes: metalsupport 
                         interaction or recowring of superficial iridium by gold particles. 
                         The fonnation of alloy ir-Au was not verified, and may be linked 
                         to the big difference of fusion temperatures presented by the two 
                         metais, result in surface -mobility difference -to metais in the 
                         reduct-ion temperature.",
            committee = "Valen{\c{c}}a, Gustavo Paim (presidente/orientador) and Cunha, 
                         David dos Santos and Cruz, Gilberto Marques",
           copyholder = "SID/SCD",
         englishtitle = "x",
             language = "pt",
                pages = "72",
                  ibi = "8JMKD3MGP3W34T/48G6CBP",
                  url = "http://urlib.net/ibi/8JMKD3MGP3W34T/48G6CBP",
           targetfile = "publicacao.pdf",
        urlaccessdate = "30 mar. 2023"
}