Influence of Adsorbates on the Electronic Structure, Bond Strain, and Thermal Properties of an Alumina-Supported Pt Catalyst

Small, Matthew W.; Sanchez, Sergio I.; Marinković, Nebojša; Frenkel, Anatoly I.; Nuzzo, Ralph G.

doi:10.1021/nn3015322

Cited by 55 publications

(90 citation statements)

References 82 publications

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“…This study highlights that the charge exchange due to both metal-support and metal-adsorbate interactions plays an important role in mediating the structural dynamics of the supported nanoscale metal catalysts. Later, the same group studied the influence of adsorbates on the electronic structure, bond strain of the ~1.0 nm Pt/γ-Al 2 O 3 catalyst [52]. They demonstrated that the Pt−Pt bonding in these small clusters is responsive to the presence of adsorbates, exhibiting pronounced coverage-dependent strains, with concomitant modifications of their electronic structures.…”

Section: Science China Materialsmentioning

confidence: 99%

X-ray absorption fine structure spectroscopy in nanomaterials

et al. 2015

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X-ray absorption fine structure (XAFS) spectroscopy has been widely used for decades in a wide range of scientific fields, including physics, chemistry, biology, materials sciences, environmental sciences, etc. This review article is devoted to the applications of XAFS in nanomaterials. The basic principles of XAFS are briefly described from the view point of practical application, including its theory, data analysis and experiments. Using selected examples from recent literatures, the power of XAFS in determination of local atomic/electronic structures is illustrated for various nanomaterials, covering metal and semiconductor nanoparticles, catalysts, core/shell structures, ultrathin nanosheets, and so on. The utilization of time-resolved XAFS technique is also briefly introduced, for in-situ probing the nucleation/growth processes of nanomaterials and identifying reaction intermediates of nanostructured catalysts under operando conditions.

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Section: Science China Materialsmentioning

confidence: 99%

X-ray absorption fine structure spectroscopy in nanomaterials

et al. 2015

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“…The reaction network in which they are involved is also very complex, due to the bifunctional nature of the system (metallic and acidic phase) and the various desired (isomerization, dehydrogenation, dehydrocyclization) and undesired (coking, hydrogenolysis, cracking) reactions. HRTEM [129][130][131][132][133] …”

Section: Acidity Of Oh Groups On Asa: On the Dominant Role Of The Stamentioning

confidence: 99%

Density functional theory simulations of complex catalytic materials in reactive environments: beyond the ideal surface at low coverage

Chizallet

Raybaud

2014

Catal. Sci. Technol.

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Most efficient heterogeneous catalysts used industrially are generally very complex systems. Far away from perfect crystallinity and well-defined oriented surfaces at low coverage, they involve structural disorder, heterogeneous site distribution with variable coordination and structural dependence upon the chemical environment. Unravelling their atomic-scale structures and understanding their roles in the catalytic reaction are not easy tasks, as the respective contributions of each type of site to the spectroscopic or catalytic responses are generally convoluted. Computational chemistry is of great help to address these issues. In the present perspective review, we highlight two relevant systems involved in numerous industrial applications: the amorphous silica alumina support; and subnanometric platinum clusters, possibly doped with tin and/or indium, supported on γ-Al 2 O 3 . The structural complexity is inherent to the amorphous nature of an oxide support on the one hand, and to the ultra-dispersed form of a mono-and multi-metallic catalyst on the other hand. In each case, Density Functional Theory (DFT) calculation was used to provide an original structure for active sites and to reveal how the corresponding multi-step reactions are influenced. Moreover, we highlight how theoretical studies including coverage effects on complex systems, induced by (T, P) reaction conditions, offer enriched perspectives with respect to studies on ideal surfaces at low coverage.

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“…This is important, because it is difficult to separate the effects of strong metal-support interactions and metal-ligand interactions on nanoparticle structure. [10][11][12][13] Second, DENs are sterically trapped within the dendrimers, and the Au surface does not interact strongly with the dendrimer host. 9 One consequence of this is that the Au surface is accessible to small molecules.…”

Section: Introductionmentioning

confidence: 99%

A theoretical and experimental examination of systematic ligand-induced disorder in Au dendrimer-encapsulated nanoparticles

Yancey¹,

Chill

Zhang

et al. 2013

Chem. Sci.

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In this paper we present a new methodology for the analysis of 1-2 nm nanoparticles using extended X-ray absorption fine structure (EXAFS) spectroscopy. Different numbers of thiols were introduced onto the surfaces of dendrimer-encapsulated Au nanoparticles, consisting of an average of 147 atoms, to systematically tune the nanoparticle disorder. An analogous system was investigated using density functional theory molecular dynamics (DFT-MD) simulations to produce theoretical EXAFS signals that could be directly compared to the experimental results. Validation of the theoretical results by comparing to experiment allows us to infer previously unknown details of structure and dynamics of the nanoparticles. Additionally, the structural information that is learned from theoretical studies can be compared with traditional EXAFS fitting results to identify and rationalize any errors in the experimental fit. This study demonstrates that DFT-MD simulations accurately depict complex experimental systems in which we have control over nanoparticle disorder, and shows the advantages of using a combined experimental/theoretical approach over standard EXAFS fitting methodologies for determining the structural parameters of metallic nanoparticles.

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Influence of Adsorbates on the Electronic Structure, Bond Strain, and Thermal Properties of an Alumina-Supported Pt Catalyst

Cited by 55 publications

References 82 publications

X-ray absorption fine structure spectroscopy in nanomaterials

X-ray absorption fine structure spectroscopy in nanomaterials

Density functional theory simulations of complex catalytic materials in reactive environments: beyond the ideal surface at low coverage

A theoretical and experimental examination of systematic ligand-induced disorder in Au dendrimer-encapsulated nanoparticles

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