Model studies of the desulfurization reactions on metal surfaces and in organometallic complexes

Wiegand, Benjamin C.; Friend, Cynthia M.

doi:10.1021/cr00012a001

Cited by 219 publications

(93 citation statements)

References 40 publications

(84 reference statements)

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“…Thiophene, a prototype of sulfur-containing compounds, has been extensively used to explore the HDS mechanisms [7][8][9]. A general conception is accepted from experimental point of view that there exist two reaction mechanisms that may compete with each other along the catalytic processes.…”

Section: Introductionmentioning

confidence: 99%

Theoretical insight into the desulfurization of thiophene on Pt(110): A density functional investigation

Zhu

Guo

et al. 2012

Journal of Molecular Catalysis A: Chemical

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Section: Introductionmentioning

confidence: 99%

Theoretical insight into the desulfurization of thiophene on Pt(110): A density functional investigation

Zhu

Guo

et al. 2012

Journal of Molecular Catalysis A: Chemical

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“…These multipole values show that these "missing" polarization and delocalized electrons in inner Mo (Mo i,VI ) probably contribute to greater electron density on the surface S atoms in bare MoS 2 , in comparison to equivalent S atoms in promoted clusters. Experimental studies of desulfurization reactions on metal surfaces and with organometallic complexes 62 show that the orientation of thiophene with respect to metal surfaces depends on the coverage of co-adsorbed hydrocarbons and sulfur atoms. On most surfaces, a parallel geometry (h 5 ) is favored for low surface coverage while a more perpendicular ring orientation (h 1 ) is favored at high surface coverage.…”

Section: Resultsmentioning

confidence: 99%

Probing topological electronic effects in catalysis: thiophene adsorption on NiMoS and CoMoS clusters

Borges¹,

Silva²

2012

J. Braz. Chem. Soc.

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Um método teórico geral em duas etapas para estudar redistribuições eletrônicas em processos catalíticos é apresentado. Na primeira etapa, teoria do funcional da densidade (DFT) é usada para otimizar completamente duas geometrias: o aglomerado que representa o catalisador e o sistema aglomerado mais molécula adsorvida. Na segunda etapa, a densidade eletrônica molecular convergida é dividida em multipolos centrados em sítios atômicos obtidos segundo uma análise de multipolos distribuídos, que fornece informação topológica detalhada da redistribuição de carga do catalisador e da molécula, antes e depois da adsorção. Esta abordagem é aplicada para a adsorção de tiofeno sobre a borda metálica 10 -10 dos catalisadores Ni(Co)MoS e comparada com a mesma reação em MoS 2 não-substituído. Energias de adsorção, geometrias e a análise de multipolos calculada indicam uma fraca adsorção do tiofeno em ambas as situações. Um modelo coulombiano para a ligação química mostra que a magnitude da ligação metal-enxofre na superfície dos catalisadores de Ni(Co)MoS promovidos é consideravelmente menor do que em MoS 2 não substituído, desta forma confirmando a origem do aumento da atividade de hidrodessulfurização (HDS) nestes catalisadores.A general two-step theoretical approach to study electronic redistributions in catalytic processes is presented. In the first step, density functional theory (DFT) is used to fully optimize two geometries: the cluster representing the catalyst and the cluster plus adsorbed molecule system. In the second step, the converged electron density is divided into multipoles centered on atomic sites according to a distributed multipole analysis which provides detailed topological information on the charge redistribution of catalyst and molecule before and after adsorption. This approach is applied to thiophene adsorption on the 10 -10 metal edge of Ni(Co)MoS catalysts and compared to the same reaction on bare MoS 2 . Calculated adsorption energies, geometries and multipole analysis indicate weak thiophene chemisorption on both cases. A Coulombic bond model showed that surface metal-sulfur bond strengths in Ni(Co)MoS promoted catalysts are considerably smaller than in bare MoS 2 , thus confirming the origin of the enhancement of hydrodesulfurization (HDS) activity in these catalysts.

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“…Wiegand's [39] studies showed that the geometry of adsorbed thiophene depends on surface coverage, and the adsorption geometry is likely to change from parallel to upright as coverage increases. This explanation was greatly proved by Cristol [40] and Itamar [41] by DFT calculations.…”

Section: Adsorption Statementioning

confidence: 99%

Desulfurization mechanism of FCC gasoline: A review

Zhao

Chen

Gao

et al. 2009

Front. Chem. Eng. China

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This paper reviews the most important developments on the desulfurization mechanism of Fluid Catalytic Cracking (FCC) gasoline. First, the origin of sulfur compounds in FCC gasoline and the current developed desulfurization approaches and technologies are briefly introduced, and then the researches on desulfurization mechanism are summarized from experimental and theoretical perspectives. Further researches on the desulfurization mechanism will lay a foundation for optimizing desulfurization sorbents and technologies.

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Model studies of the desulfurization reactions on metal surfaces and in organometallic complexes

Abstract: ContentsTABLE I. Electron Energy Loss Assignments for 1.

Cited by 219 publications

References 40 publications

Theoretical insight into the desulfurization of thiophene on Pt(110): A density functional investigation

Theoretical insight into the desulfurization of thiophene on Pt(110): A density functional investigation

Probing topological electronic effects in catalysis: thiophene adsorption on NiMoS and CoMoS clusters

Desulfurization mechanism of FCC gasoline: A review

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