Cluster size effects on CO oxidation activity, adsorbate affinity, and temporal behavior of model Aun∕TiO2 catalysts

Lee, Sungwon; Fan, Chengyu; Wu, Tianpin; Anderson, Scott L.

doi:10.1063/1.2035098

Cited by 88 publications

(100 citation statements)

References 37 publications

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“…CO oxidation is also important in other areas such as respiratory protection and fuel gas cleanup. Gold based catalysts are employed for low temperature CO oxidation [121], and have been studied extensively in the condensed phase [122][123][124][125][126][127][128][129] and in the gas phase [130][131][132][133][134], but a search for alternative, low-cost, and noble metal free materials has led to the study of transition metal and metal oxide catalysts [135][136][137][138] for such reactions. In the following we present three studies dealing with the oxidation reactions of CO catalyzed by neutral gold clusters, iron oxide, and cobalt oxide clusters.…”

Section: Co Oxidationmentioning

confidence: 99%

Gas phase chemistry of neutral metal clusters: Distribution, reactivity and catalysis

Yin

Bernstein

2012

International Journal of Mass Spectrometry

164

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Section: Co Oxidationmentioning

confidence: 99%

Gas phase chemistry of neutral metal clusters: Distribution, reactivity and catalysis

Yin

Bernstein

2012

International Journal of Mass Spectrometry

164

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“…The experimental apparatus, which has been described in detail previously, 40,41 consists of a mass-selected ion beamline attached to an ultrahigh vacuum (UHV) chamber with a base pressure during reaction studies of ∼1.5 × 10 −10 Torr. The setup allows in situ sample preparation and characterization by XPS, Auger electron spectroscopy (AES), low energy He + ion scattering (ISS), and temperature-programmed desorption/reaction.…”

Section: A Apparatusmentioning

confidence: 99%

CO adsorption and desorption on size-selected Pdn/TiO2(110) model catalysts: Size dependence of binding sites and energies, and support-mediated adsorption

Kaden

Kunkel

Roberts

et al. 2012

The Journal of Chemical Physics

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The nature of CO adsorption on Pd(n)/TiO(2)(110) (n = 1, 2, 7, 20) has been examined using temperature-programmed desorption (TPD), temperature-dependent helium ion scattering (TD-ISS), and X-ray photoelectron spectroscopy (XPS). All samples contain the same number of Pd atoms (0.10 ML-equivalent) deposited as different size clusters. The TPD and TD-ISS show that CO binds in two types of sites associated with the Pd clusters. The most stable sites are on top of the Pd clusters ("on-top" sites), however, there are also less stable sites, in which CO is bound in association with, but not on top of the Pd ("peripheral" sites). For saturation CO coverage over a fixed atomic concentration of Pd (present in the form of Pd(n) clusters of varying size), the population of CO in peripheral sites decreases with increasing cluster size, while the on-top site population is size-independent. This is consistent with what geometric considerations would predict for the density of the two types of sites, provided the clusters adsorb predominantly as 2D islands, which ISS results suggest to be the case. The XPS analysis indicates that CO-Pd binding is dominated by π-backbonding to the Pd(n) clusters. The results also show evidence for efficient support-mediated adsorption (reverse-spillover) of CO initially impinging on TiO(2) to binding sites associated with the Pd clusters.

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“…These features make nanoalloys even more promising than pure clusters to develop applications in several biomedical, catalytic, optical and electronic technologies [1][2][3][4][5][6][7][8][9][10] . These differences arise from the interplay between nanoscale and alloying effects, which in principle depend on size and composition.…”

Section: Introductionmentioning

confidence: 99%

System-dependent melting behavior of icosahedral anti-Mackay nanoalloys

et al. 2013

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Anti-Mackay icosahedral clusters of composition Ag 32 M 13 , where M is either Cu,Ni, or Co, have been recently shown to possess special structural stability both by calculations and experiments. These nanoalloys assume a core-shell arrangement, with an icosahedral core of 13 M atoms surrounded by an Ag shell of anti-Mackay structure. In this paper we study the melting of these three nanoalloys, showing that, despite the close similarity of the structures, melting takes place through quite different mechanisms. In particular, we find that Ag 32 Co 13 and Ag 32 Ni 13 present a premelting phenomenon which involves only the shell of the cluster while the core melts at higher temperatures, in agreement with previous calculations. On the contrary, in Ag 32 Cu 13 , melting occurs through stages that involve the shell and the core at the same time. These findings are rationalized in terms of the different features of the energy landscape of these nanoalloys. Our simulations, in which special care has been devoted to avoid non-ergodicity problems, show also that the particles keep their core-shell structures even in the liquid phase, indicating an incomplete miscibility of Ag with Ni, Co or Cu at the nanoscale up to quite high temperatures.We start off our results on investigation into the melting mechanism of anti-Mackay nanoalloys with presenting caloric curves.Since the total potential energy of the cluster is written, within the Gupta model, by a sum of individual atomic energies, it is possible to associate energies to the core and to the shell separately, by summing atomic energies on core and shell atoms 1-33 | 7

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Cluster size effects on CO oxidation activity, adsorbate affinity, and temporal behavior of model Aun∕TiO2 catalysts

Cited by 88 publications

References 37 publications

Gas phase chemistry of neutral metal clusters: Distribution, reactivity and catalysis

Gas phase chemistry of neutral metal clusters: Distribution, reactivity and catalysis

CO adsorption and desorption on size-selected Pdn/TiO2(110) model catalysts: Size dependence of binding sites and energies, and support-mediated adsorption

System-dependent melting behavior of icosahedral anti-Mackay nanoalloys

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