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

Zhu, Houyu; Lu, Xiaoqing; Guo, Wenyue; Li, Longfei; Zhao, Lianming; Shan, Honghong

doi:10.1016/j.molcata.2012.05.011

Cited by 16 publications

(16 citation statements)

References 37 publications

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“…The Pt 6s orbital is mainly distributed above the Fermi level, indicating that it is almost empty. Thus, the electronic configuration of the Pt atom is close to 5d 10 and the nearly full d-shell occupation lifts the d-band center, similar to the previously studied Pt@graphene where the valence electrons in the single Pt atom adopt a singlet state (5d 10 ) rather than a triplet state (5d 9 6s 1 ) configuration. 22 In summary, the formation of Pt δ− in Pt x /α−Al 2 O 3 could promote the electron transfer toward the C−S antibonding orbitals of CH 3 SH and facilitate the C−S bond cleavage.…”

Section: Support Effectssupporting

confidence: 78%

“…Although metal particles supported on oxides are a common motif in heterogeneous catalysis, the exact nature of the active sites and their locations are still not well understood. It is commonly accepted that the active sites are present on the metal particles and the majority of previous works focused on the catalytic activity of close-packed transition-metal surfaces, such as thiophene desulfurization on Ni(100), Ni(110), Pt(111), and Pt(110), CO oxidation on Ni(111), Pt(111), and Au(111), and the water gas shift (WGS) reaction on Cu(111), Pt(111), and Au(111) . However, metal nanoparticles (NPs) contain not only ideal terminations but also edges and steps that can be more active and display different adsorption and reaction properties than extended surfaces .…”

Section: Introductionmentioning

confidence: 99%

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Unraveling the Active Site and Mechanism for C–S Bond Activation in Alumina-Supported Pt Catalysts: Ab Initio Insights into Catalytic Desulfurization

Zhu

et al. 2019

J. Phys. Chem. C

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Understanding the active sites of metal/oxide catalysts is of great significance in heterogeneous catalysis. In this work, we performed periodic density functional theory calculations to study the C–S bond activation of CH3SH on Pt/α-Al2O3 catalysts. Five different types of sites were investigated, which are single Pt-atom site in Pt1/α-Al2O3, Pt(111) site in Pt slab/α-Al2O3, and top-edge, interface, and atop-Al sites in Pt nanorod/α-Al2O3, respectively. In contrast to the common thought that lower-coordinated atoms at the surface of small metal nanoparticles (NPs) would lead to the higher reaction activity, the present work clearly demonstrates that the coordination-unsaturated sites over Pt NPs have subtle influence on the C–S bond scission. On the basis of energetic analysis, we propose that the interfacial Pt (type I) site, summarized as the “Pt–Al” dual perimeter site, could be the active site for the C–S bond activation. The presence of alumina support adversely impacts catalytic performance of Pt nanoparticle itself but exerts positive influence along the Pt/alumina interfacial boundary. The origin of this positive effect on the C–S bond activation over the “Pt–Al” dual perimeter site can be understood from the electronic perspective, in which the active interfacial Pt atoms act as electron acceptors (Ptδ−) while alumina support acts as electron donors. The electron-rich property of Ptδ− and the energy-level downshifting of the C–S antibonding orbitals of CH3SH both facilitate the electron transfer from Pt to the C–S antibonding orbitals, leading to subsequent C–S bond cleavage. The electron transferred from the support to Pt is the determining factor to activate the C–S bond of CH3SH and is dependent on the termination type of alumina. The present work provides geometric and electronic insights into the nature of active sites and sheds light on the design of more active metal/oxide catalysts toward catalytic desulfurization.

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Section: Support Effectssupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Unraveling the Active Site and Mechanism for C–S Bond Activation in Alumina-Supported Pt Catalysts: Ab Initio Insights into Catalytic Desulfurization

Zhu

et al. 2019

J. Phys. Chem. C

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“…For Pt(110) several different adsorption geometries were determined, with the theoretical adsorption energies ranging from 0.97 to 0.99 eV for the upright adsorption geometries, and 1.68 to 2.87 eV for the flat adsorption geometries. 45 The values calculated for the desorption energy of S on Pt are much higher compared to the theoretical values stated in the literature. An explanation for the discrepancy between our values and the values in the literature could be the influence of the electric field, involved in the desorption process, different crystallographic facets being present on the atom probe substrate compared to the DFT calculations, and the choice of parameters for the DFT calculations.…”

Section: ■ Experimental Sectionmentioning

confidence: 62%

“…At high thiophene coverage and thus inclined orientation, an adsorption energy of 0.86 eV and 1.55 eVwere calculated. For Pt(110) several different adsorption geometries were determined, with the theoretical adsorption energies ranging from 0.97 to 0.99 eV for the upright adsorption geometries, and 1.68 to 2.87 eV for the flat adsorption geometries . The values calculated for the desorption energy of S on Pt are much higher compared to the theoretical values stated in the literature.…”

Section: Resultsmentioning

confidence: 83%

A New Approach to Understand the Adsorption of Thiophene on Different Surfaces: An Atom Probe Investigation of Self-Assembled Monolayers

Eder¹,

Felfer

Gault

et al. 2017

Langmuir

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Atom probe tomography was used to analyze self-assembled monolayers of thiophene on different surfaces, including tungsten, platinum, and aluminum, where the tungsten was examined in both pristine and oxidized forms. A glovebag with controlled atmospheres was used to alter the level of oxidation for tungsten. It was shown that different substrates lead to substantial changes in the way thiophene adsorbs on the surface. Furthermore, the oxidation of the surface strongly influenced the adsorption behavior of the thiophene molecules, leading to clear differences in the amounts and compositions of field evaporated ions and molecular ions.

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“…Mechanistically, it is well-known that 4,6-DMDBT is desulfurized by either a hydrogenation (HYD) route or a direct desulfurization (DDS) route [4,18]. A group of researches [15,[19][20][21][22][23][24][25] proposed that 4,6-DMDBT is adsorbed following π and σ adsorptions: in the former, the aromatic ring of the 4,6-DMDBT is adsorbed on the active site, whereas in the latter the sulfur heteroatom is the one being adsorbed on. It suggests that HYD route involves both π and σ adsorptions while the DSD route involves only σ adsorption.…”

Section: Introductionmentioning

confidence: 99%

Role of Pt–Pd/γ-Al2O3 on the HDS of 4,6-DMBT: Kinetic modeling & contribution analysis

Castillo‐Araiza

Chávez

Dutta

et al. 2015

Fuel Processing Technology

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The purpose of this study is to provide insights on the function of noble metals, namely Pt-Pd catalytic system, on the hydrodesulfurization (HDS) of alkyl-substituted dibenzothiophenes (a-DBTs) by means of kinetic modeling and contribution analyses. A series of Pt-Pd systems (1% wt. nominal loading) supported on γ-Al 2 O 3 (0-100, 20-80, 50-50, 80-20 and 100-0; %mol Pt-%mol Pd) are synthesized and evaluated during the HDS of 4,6dimethyldibenzothiophene (4,6-DMDBT) at operating conditions relevant for industry: 320°C, 500 ppm of S and an H 2 pressure of 5.5 MPa. A summary of their characterization is presented as reference herein. Kinetic model based on a Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism and contribution analysis based on predicted reaction rates give rise to the following findings: the bimetallic catalyst 8Pt-2Pd/γ-Al 2 O 3 (80-20; %mol Pt-%mol Pd) leads to the highest activity; in all Pt-Pd/γ-Al 2 O 3 systems, Pt favors desulfurization reactions, i.e., 4,6-DMDBT to 3,3′-dimethylphenyl (3,3′-DMBP) and 4,6-dimethyltetrahydrodibenzothiophene (4,6-DM-th-DBT) to MCHT, whereas Pd favors hydrogenation of 4,6-DMDBT to 4,6-DM-th-DBT; and 4,6-DMDBT and methylcyclohexyltoluene (MCHT) are the hydrocarbons with the lowest and highest affinity to be adsorbed on the active sites from the studied Pt-Pd/γ-Al 2 O 3 systems, respectively.

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

Cited by 16 publications

References 37 publications

Unraveling the Active Site and Mechanism for C–S Bond Activation in Alumina-Supported Pt Catalysts: Ab Initio Insights into Catalytic Desulfurization

Unraveling the Active Site and Mechanism for C–S Bond Activation in Alumina-Supported Pt Catalysts: Ab Initio Insights into Catalytic Desulfurization

A New Approach to Understand the Adsorption of Thiophene on Different Surfaces: An Atom Probe Investigation of Self-Assembled Monolayers

Role of Pt–Pd/γ-Al2O3 on the HDS of 4,6-DMBT: Kinetic modeling & contribution analysis

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