Ultrathin metal films on a metal oxide surface: Growth of Au on<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">TiO</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>(110)

Zhang, Lei; Persaud, Rajendra; Madey, Theodore E.

doi:10.1103/physrevb.56.10549

Cited by 198 publications

(182 citation statements)

References 32 publications

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“…1. It is well-known that binding energy of gold decreases to that of bulk gold as the particle size of the gold cluster increases and approaches to bulk gold [8,9,[37][38][39][40]. Our experimental value for the 4f binding energy of Au 0 is 85.3 eV at the beginning and approaches to 84.3 eV.…”

Section: Resultsmentioning

confidence: 52%

“…Information related to the mechanism of the process and/or the fate of the reduced products (especially whether or not cluster formation or nucleation also take place) are needed. From this aspect XPS is particularly suitable since a significant chemical shift develops to correlate with the size of gold clusters [37][38][39][40][41][42][43][44][45][46]. Accordingly, we have recently reported an XPS investigation of HAuCl 4 deposited on SiO 2 /Si substrate and in PMMA matrix where we have demonstrated the formation of gold nanoclusters by X-ray induced reduction [47].…”

Section: Introductionmentioning

confidence: 99%

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X-ray induced reduction of Au and Pt ions on silicon substrates

Ozkaraoglu

Tunç

Süzer

2007

Surface and Coatings Technology

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Prolonged exposure to X-rays of HAuCl 4 , PtCl 4 and their mixtures, deposited from an aqueous solution onto a silicon substrate, causes chemical reduction of the metal ions to their metallic states. The corresponding oxidation reaction is the conversion of chloride ions to chlorine. The resultant metal atoms aggregate to form metallic/bimetallic nanoclusters as evidenced from their XPS chemical shifts. Hence, X-rays are usable for in-situ nanoparticle production or for direct-writing applications on silicon substrates.

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Section: Resultsmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 99%

X-ray induced reduction of Au and Pt ions on silicon substrates

Ozkaraoglu

Tunç

Süzer

2007

Surface and Coatings Technology

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“…They carried out a careful study of loading effects on this reaction and found a minimum in rate at a similar loading to our results above, though no reason for this minimum was deduced. Some studies suggest that gold can take on two distinct morphologies when deposited on a planar TiO2 surface [18], and it may be that the two peaks represent the maxima for these two. A mechanism for this reaction on Pd/TiO2 was proposed earlier [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Photocatalysis by au nanoparticles: Reforming of methanol

et al. 2004

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Au/TiO2 catalysts were prepared by incipient wetness impregnation and tested for the room temperature photocatalytic reforming of methanol in aqueous solution to produce hydrogen. These catalysts proved to be active for this reaction, with the dependence on loading of gold showing a double maximum in yield at 0.2 and 2 weight % with a low rate below 0.01% and above 10%. A model is proposed for the reaction, involving band gap excitation of titania electrons to produce O -species which are then used to oxidise the methanol via adsorbed methoxy, which is formed by dehydrogenation on the metal component. The reaction is truly bi-functional and only takes place at the interface between the metal and the support.An ideal for the future well-being of the human population of the world (and for the biota as a whole) is to find an energy source which has the following properties: 1 It must be environmentally benign, producing minimal pollution of any kind, and taking up as little useful space as possible; 2 It must have usable energy density; 3 It should be usable on a local basis -strategically eliminating dependence upon external influences; 4 It should be economically viable, which is not as simple a point as might at first be imagined, since it involves future costs of materials and government subsidies which are currently in place for various energy sources (nuclear, for instance) and which will, in turn, relate closely to item 3;5 It needs to be technologically feasible and available. In many ways hydrogen best fits most of these points, except for 4. It fits 1, provided that it is part of a cycle, that is hydrogen is produced from water and is burned back to water to produce energy from the exothermic oxidation of hydrogen. 2 also applies, but only if the hydrogen is used at the source of production, or is transported in a densified form (for instance, as a liquid, a high pressure gas, or condensed into a microporous high surface area solid). The technology is currently available to achieve 3 and 5, though the technology certainly can be improved. 4 is the main problem, but as stated above, hydrogen may well become economically viable in the event of a big increase in the price of oil or big taxes on fossil fuels more generally, related to the pollution they cause and their strong connection to global warming. More importantly for the West, that part of the world is currently unrealistically dependent on oil supplies from unstable parts of the world. Any responsible Western state should be investing VERY heavily, right now, in alternative energy sources, one of these being renewable and minimally-polluting hydrogen production.The objective of this paper, then, is to describe one method of producing hydrogen, that is, by using photocatalysis, which has the potential to be used to split water using sunlight. However, the rates of this reaction are quite low and so the work described here focuses on the room temperature reforming of methanol, which does effectively split water. Previous work in this group [1]...

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“…3,19,20 While Pt/ TiO 2 has been the prototype system for strong-metal-support interaction where the reactivity of the metal particle is strongly modified by the presence of the support either by an electronic interaction between the metal and the support or by a chemical exchange that leads to the encapsulation of Pt clusters by reduced oxides, 16,20,21 Au/ TiO 2 does not undergo significant encapsulation under equivalent annealing conditions. 22 In addition to experimental techniques, computational methods based on density functional theory ͑DFT͒ calculations have become a powerful research tool for investigating the geometric and electronic properties of metaloxide interfaces. The common computational approach for this study employs the conventional unit cell model with periodic boundary conditions.…”

Section: Introductionmentioning

confidence: 99%

Modeling the noble metal/TiO2 (110) interface with hybrid DFT functionals: A periodic electrostatic embedded cluster model study

Ammal

Heyden

2010

The Journal of Chemical Physics

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Articles you may be interested inEmbedded cluster density functional and second-order Møller-Plesset perturbation theory study on the adsorption of N2 on the rutile (110) This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation. The interaction of Au n and Pt n ͑n=2,3͒ clusters with the stoichiometric and partially reduced rutile TiO 2 ͑110͒ surfaces has been investigated using periodic slab and periodic electrostatic embedded cluster models. Compared to Au clusters, Pt clusters interact strongly with both stoichiometric and reduced TiO 2 ͑110͒ surfaces and are able to enhance the reducibility of the TiO 2 ͑110͒ surface, i.e., reduce the oxygen vacancy formation energy. The focus of this study is the effect of Hartree-Fock exchange on the description of the strength of chemical bonds at the interface of Au/Pt clusters and the TiO 2 ͑110͒ surface. Hartree-Fock exchange helps describing the changes in the electronic structures due to metal cluster adsorption as well as their effect on the reducibility of the TiO 2 surface. Finally, the performance of periodic embedded cluster models has been assessed by calculating the Pt adsorption and oxygen vacancy formation energies. Cluster models, together with hybrid PBE0 functional, are able to efficiently compute reasonable electronic structures of the reduced TiO 2 surface and predict charge localization at surface oxygen vacancies, in agreement with the experimental data, that significantly affect computed adsorption and reaction energies.

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Ultrathin metal films on a metal oxide surface: Growth of Au onTiO2(110)

Cited by 198 publications

References 32 publications

X-ray induced reduction of Au and Pt ions on silicon substrates

X-ray induced reduction of Au and Pt ions on silicon substrates

Photocatalysis by au nanoparticles: Reforming of methanol

Modeling the noble metal/TiO2 (110) interface with hybrid DFT functionals: A periodic electrostatic embedded cluster model study

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