Growth of Ordered Ultrathin Tungsten Oxide Films on Pt(111)

Li, Zhenjun; Zhang, Zhenrong; Kim, Yu Kwon; Smith, R. Scott; Netzer, H.; Kay, Bruce D.; Rousseau, Roger; Dohnálek, Zdenek

doi:10.1021/jp1108976

Cited by 42 publications

(77 citation statements)

References 67 publications

(108 reference statements)

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“…Further increase of the annealing temperature to 800 K results in small changes of the peak line shape and a small red shift to 1014 cm À1 . On the basis of previous DFT and IRAS studies, 13,22,37,44 this peak can be assigned to the stretching mode of terminal WdO. The lack of a peak at 859 cm À1 , which was previously assigned to the WÀOÀW ring stretching mode of the clusters, provides strong evidence that the clusters are either lying flat on the surface and/or dissociated to monomers as suggested by the STM results and DFT calculations in the previous section.…”

Section: Spectroscopic Characterization Of (Wo 3 ) 3 On Feo(111)supporting

confidence: 60%

“…We start with analysis of the vibrational modes of an isolated, gas-phase (WO 3 ) 3 cluster. As in our previous work on (WO 3 ) 3 films on Pt(111), 22 the vDOS was obtained by autocorrelation of the fluctuations of the various WÀO bonds in the cluster. For the WÀOÀW mode seen experimentally at 859 cm À1 , we find that this peak correlates well with a peak in the vDOS at 925 cm À1 , which is blue-shifted from experiment.…”

Section: Spectroscopic Characterization Of (Wo 3 ) 3 On Feo(111)mentioning

confidence: 99%

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Preparation, Characterization, and Catalytic Properties of Tungsten Trioxide Cyclic Trimers on FeO(111)/Pt(111)

Zhang

et al. 2011

J. Phys. Chem. C

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The structure and catalytic activity of tungsten oxide clusters formed via sublimation of monodispersed cyclic (WO3)3 onto FeO(111)/Pt(111) has been studied by a combination of scanning tunneling microscopy (STM), X-ray photoemission spectroscopy (XPS), infrared reflection–absorption spectroscopy (IRAS), temperature-programmed desorption (TPD), and density functional theory (DFT). After (WO3)3 deposition, STM images reveal new features composed of three bright maxima arranged in a equilateral triangular configuration with an edge length of ∼10 Å. This length is significantly larger than the size of (WO3)3, indicating that the clusters dissociated. This conclusion is corroborated by DFT calculations showing that cluster dissociation into surface-bound WO3 monomers is exothermic and kinetically feasible at 300 K. The dissociation is accompanied by significant FeO(111) rearrangements with the Fe ions being pulled on top of the surface and bonded to the WO3 fragments. Both surface spectroscopies (XPS and IRAS) and calculations indicate that the W ions in the WO3 monomers remain in their original oxidation state (6+) and possess a single terminal WO group. TPD studies show that this system does not efficiently catalyze alcohol dehydration. This inactivity is explained on the basis of the reaction mechanism calculated by DFT.

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Section: Spectroscopic Characterization Of (Wo 3 ) 3 On Feo(111)supporting

confidence: 60%

Section: Spectroscopic Characterization Of (Wo 3 ) 3 On Feo(111)mentioning

confidence: 99%

Preparation, Characterization, and Catalytic Properties of Tungsten Trioxide Cyclic Trimers on FeO(111)/Pt(111)

Zhang

et al. 2011

J. Phys. Chem. C

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“…While this is peculiar, it is not the first observation of this phenomenon. In fact there have been several reports of inert metals exhibiting charge‐transfer with metal‐oxides on the nano‐scale, such as Au nanoparticles on MgO supports,29 MgO films on Au surfaces,30 thin WO 3 films on Pt surfaces,31 MoO 3 films on Au surfaces,32, 33 Au nano‐particles an TiO 2 ,34 and V 2 O 5 films on Au 35. Although this phenomenon has been modeled computationally,32, 36 and lattice strain appears to be closely related to the charge‐transfer process, this behaviour is still under debate 37.…”

Section: Discussionmentioning

confidence: 99%

Metal/Metal‐Oxide Interfaces: How Metal Contacts Affect the Work Function and Band Structure of MoO₃

Greiner

Chai

Helander

et al. 2012

Adv Funct Materials

350

304

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When transition metal oxides are used in practical applications, such as organic electronics or heterogeneous catalysis, they often must be in contact with a metal. Metal contacts can affect an oxide's chemical and electronic properties within the first few nanometers of the contact, resulting in changes to an oxide's chemical reactivity, conductivity, and energy‐level alignment properties. These effects can alter an oxide's ability to perform its intended function. Thus, the choice of contacting metal becomes an important design consideration when tailoring the properties of transition‐metal oxide thin films or nanoparticles. Here, metal/metal‐oxide interfaces involving a widely used oxide in organic electronics, MoO3, are examined. It is demonstrated that metal contacts tend to reduce the Mo6+ cation to lower oxidation states and, consequently, alter MoO3’s valence electronic structure and work function when the oxide layer is very thin (less than 10 nm). MoO3 becomes semimetallic and has a lower work function near metal contacts. The observed behavior is attributed to two causes: 1) charge transfer from the metal Fermi level into MoO3’s low‐lying conduction band and 2) an oxidation‐reduction reaction between the metal and MoO3 that results in oxidation of the metal and reduction of MoO3. These results illustrate how interfaces are important to an oxide's ability to provide energy‐level alignment.

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“…These values are in good agreement with the experimental frequencies reported for the gasphase (WO 3 ) 3 nanoclusters, 859, 975, and 1014 cm À1 . 64 While for the (WO 3 ) 3 clusters adsorption on the defective MgO/ Ag(001) lms, the vibrational spectrum becomes considerably more complex compared to gas-phase (WO 3 ) 3 clusters, due to the distortion of the supported (WO 3 ) 3 clusters (Fig. 5b).…”

Section: Observable Propertiesmentioning

confidence: 98%

A DFT study of (WO₃)₃nanoclusters adsorption on defective MgO ultrathin films on Ag(001)

et al. 2017

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Growth of Ordered Ultrathin Tungsten Oxide Films on Pt(111)

Cited by 42 publications

References 67 publications

Preparation, Characterization, and Catalytic Properties of Tungsten Trioxide Cyclic Trimers on FeO(111)/Pt(111)

Preparation, Characterization, and Catalytic Properties of Tungsten Trioxide Cyclic Trimers on FeO(111)/Pt(111)

Metal/Metal‐Oxide Interfaces: How Metal Contacts Affect the Work Function and Band Structure of MoO₃

A DFT study of (WO₃)₃nanoclusters adsorption on defective MgO ultrathin films on Ag(001)

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Growth of Ordered Ultrathin Tungsten Oxide Films on Pt(111)

Cited by 42 publications

References 67 publications

Preparation, Characterization, and Catalytic Properties of Tungsten Trioxide Cyclic Trimers on FeO(111)/Pt(111)

Preparation, Characterization, and Catalytic Properties of Tungsten Trioxide Cyclic Trimers on FeO(111)/Pt(111)

Metal/Metal‐Oxide Interfaces: How Metal Contacts Affect the Work Function and Band Structure of MoO3

A DFT study of (WO3)3nanoclusters adsorption on defective MgO ultrathin films on Ag(001)

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Product

Resources

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Metal/Metal‐Oxide Interfaces: How Metal Contacts Affect the Work Function and Band Structure of MoO₃

A DFT study of (WO₃)₃nanoclusters adsorption on defective MgO ultrathin films on Ag(001)