Effect of Au doping of Ni/Al2O3 catalysts used in steam reforming of methane: Mechanism, apparent activation energy, and compensation effect

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dc.contributor.authorde Oliveira Rocha, Kleper [UNESP]
dc.contributor.authorMarques, Clélia Mara Paula
dc.contributor.authorBueno, José Maria Correa
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUniversidade Federal de São Carlos (UFSCar)
dc.date.accessioned2019-10-06T15:48:58Z
dc.date.available2019-10-06T15:48:58Z
dc.date.issued2019-11-02
dc.description.abstractInvestigation was made of the effect of addition of Au to 15%Ni/Al2O3 catalysts used in the steam reforming of methane. The addition of Au was performed by impregnation of reduced Ni catalysts. The catalysts were characterized by X-ray diffraction (XRD) and diffuse reflectance infrared Fourier transform spectroscopy of adsorbed CO (DRIFTS-CO). DRIFTS-CO showed that Au modified the surface structure of Ni. Au blocked the low coordination Ni sites with high electron density and high activity for CH4 activation. Furthermore, it modified the high coordination Ni, causing geometric and electronic effects, changing the CO adsorption from bridge to linear form, and increasing the electron density of Ni-Au, relative to Ni at sites such as Ni(1 1 1). Addition of Au to the Ni catalysts had a strong influence on the activation of CH4. A compensation effect was observed between the apparent activation energy (Eaapp) and the natural logarithm of the pre-exponential factor (ln(k0)), obtained by fitting of the Arrhenius equation to the rate of the overall reaction. Greater Au addition decreased the catalytic activity, with linear increase of Eaapp with increase of ln(k0). These results suggested that the intermediates formed by decomposition of CH4, in the step determining the overall velocity, presented low interaction with the Ni surface. The proposed mechanisms also suggested that the activation of CH4 required two Ni neighbor sites.en
dc.description.affiliationDepartment of Chemistry Science Faculty São Paulo State University (UNESP), Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, Vargem Limpa
dc.description.affiliationDepartment of Chemistry Federal University of São Carlos (UFSCar), C.P. 676
dc.description.affiliationDepartment of Chemical Engineering Federal University of São Carlos (UFSCar), C.P. 676
dc.description.affiliationUnespDepartment of Chemistry Science Faculty São Paulo State University (UNESP), Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, Vargem Limpa
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.description.sponsorshipIdFAPESP: 2018/012585
dc.description.sponsorshipIdCNPq: 301027/2018-8
dc.format.extent844-852
dc.identifierhttp://dx.doi.org/10.1016/j.ces.2019.06.049
dc.identifier.citationChemical Engineering Science, v. 207, p. 844-852.
dc.identifier.doi10.1016/j.ces.2019.06.049
dc.identifier.issn0009-2509
dc.identifier.scopus2-s2.0-85068582948
dc.identifier.urihttp://hdl.handle.net/11449/187843
dc.language.isoeng
dc.relation.ispartofChemical Engineering Science
dc.rights.accessRightsAcesso aberto
dc.sourceScopus
dc.subjectApparent activation energy
dc.subjectAu-promoted Ni catalysts
dc.subjectCompensation effect
dc.subjectNi/Al2O3 catalysts
dc.subjectSteam reforming of methane
dc.titleEffect of Au doping of Ni/Al2O3 catalysts used in steam reforming of methane: Mechanism, apparent activation energy, and compensation effecten
dc.typeArtigo

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