Counting electrons on supported nanoparticles

Lykhach, Yaroslava; Kozlov, Sergey M.; Škála, Tomáš; Tovt, Andrii; Stetsovych, Vitalii; Tsud, Nataliya; Dvořák, Filip; Johánek, Viktor; Neitzel, Armin; Mysliveček, Josef; Fabris, Stefano; Matolín, Vladimı́r; Neyman, Konstantin M.; Libuda, Jörg

doi:10.1038/nmat4500

Cited by 518 publications

(532 citation statements)

References 41 publications

(21 reference statements)

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“…While this led to good agreement between experiment and simulation and also to agreement with up to date literature about the direction of charge transfer 26 concerns have been raised about the validity of the approximation assuming a point-like tip and fixed electrical charges, in particular in the 25 presence of conductive samples, [27][28][29][30] and it was suggested to involve also van der Waals forces. 31 Most charges in the oxide support are fixed to defects, and in the metal nanoparticle the charges at the interface are largely immobilized by the attraction to the counter charge in close proximity across the interface, but there are mobile conduction electrons which render the particles polarizable by the applied voltage on the tip.…”

Section: Possible Effects Of the Finite Tip Size On The Kelvin Probe supporting

confidence: 74%

Charge Polarization at Catalytic Metal–Support Junctions. Part B: Theoretical Modeling of Kelvin Probe Force Microscopy

Kittel

Roduner

2016

J. Phys. Chem. C

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Existing models for the analysis of Kelvin probe microscopy experiments are extended and used to analyze the experimental electrical potential profiles for a Pt/TiO 2 model nanoparticle.The derived model reproduces in detail the Kelvin probe image that reveals a characteristic ring-shaped negative charge zone at the surface around the particle: A planar negative charge zone at the surface of the support extends beyond the diameter of the Pt particle. It is compensated mostly by a planar layer of positive charges in the metal across the interface, and by a smaller number of positive charges at the metal-air interface. These latter charges determine the positive electrical potential of the metal particle, and they are likely responsible for the extent of the metal-support interaction in catalytic reactions.

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Section: Possible Effects Of the Finite Tip Size On The Kelvin Probe supporting

confidence: 74%

Charge Polarization at Catalytic Metal–Support Junctions. Part B: Theoretical Modeling of Kelvin Probe Force Microscopy

Kittel

Roduner

2016

J. Phys. Chem. C

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“…5,8,33,34,41,42 is separated from its periodically repeated images in the neighboring unit cells in the three Cartesian directions by at least 0.9 nm to minimize the spurious particle-particle interactions. Γ-point calculations are performed.…”

Section: Models With Ceria Supportmentioning

confidence: 99%

Can the state of platinum species be unambiguously determined by the stretching frequency of an adsorbed CO probe molecule?

Aleksandrov

Neyman

Hadjiivanov

et al. 2016

Phys. Chem. Chem. Phys.

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138

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Electronic Supplementary Information (ESI) available: Information includes sketches of all modeled Pt8(CO) complexes in gas phase and some of their energetic and structural characteristics, structure of e-reg/(CO)2 complex, and figure with the changes of the CO stretching frequency versus oxidation state and Bader charge of mononuclear platinum species. See DOI: 10.1039/x0xx00000x The paper addresses possible ambiguities in determination of the state of platinum species by the stretching frequency of a CO probe, which is a common technique for characterization of platinum-containing catalytic systems. We present a comprehensive comparison of the available experimental data with our theoretical modeling (density functional) results of pertinent systems -platinum surface, nanoparticles and clusters as well as reduced or oxidized platinum moieties on ceria support. Our results for CO adsorbed on-top on metallic Pt . This trend corroborates the Kappers-van der Maas correlation derived from analysis of experimental stretching frequency of CO adsorbed on platinum-containing samples on different supports. We also analyzed the effect of the charge of platinum species on the CO frequency. Based on the calculated vibrational frequencies of CO in various model systems, we concluded that the actual state of the platinum species may be mistaken based only on the measured value of the C-O vibrational frequency due to overlapping regions of frequencies corresponding to different types of species. In order to identify the actual state of platinum species one has to combine this powerful technique with other approaches.

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“…The most common reason for the deactivation of copper‐based catalysts is metal nanoparticle sintering, which reduces the metallic surface area available for catalysis. Concerning the Cu/TiO 2 catalyst, no signs of severe sintering were observed, which we believe is owed to a strong metal–support interaction (SMSI),41, 42 or an electronic metal–support interaction (EMSI), as proposed by Lykhach et al 43. and Campbell 44.…”

mentioning

confidence: 58%

Microwave‐Assisted Selective Hydrogenation of Furfural to Furfuryl Alcohol Employing a Green and Noble Metal‐Free Copper Catalyst

et al. 2016

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Green, inexpensive, and robust copper‐based heterogeneous catalysts achieve 100 % conversion and 99 % selectivity in the conversion of furfural to furfuryl alcohol when using cyclopentyl‐methyl ether as green solvent and microwave reactors at low H2 pressures and mild temperatures. The utilization of pressurized microwave reactors produces a 3–4 fold increase in conversion and an unexpected enhancement in selectivity as compared to the reaction carried out at the same conditions using conventional autoclave reactors. The enhancement in catalytic rate produced by microwave irradiation is temperature dependent. This work highlights that using microwave irradiation in the catalytic hydrogenation of biomass‐derived compounds is a very strong tool for biomass upgrade that offers immense potential in a large number of transformations where it could be a determining factor for commercial exploitation.

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Counting electrons on supported nanoparticles

Cited by 518 publications

References 41 publications

Charge Polarization at Catalytic Metal–Support Junctions. Part B: Theoretical Modeling of Kelvin Probe Force Microscopy

Charge Polarization at Catalytic Metal–Support Junctions. Part B: Theoretical Modeling of Kelvin Probe Force Microscopy

Can the state of platinum species be unambiguously determined by the stretching frequency of an adsorbed CO probe molecule?

Microwave‐Assisted Selective Hydrogenation of Furfural to Furfuryl Alcohol Employing a Green and Noble Metal‐Free Copper Catalyst

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