Selective Thermal Reduction of Single-layer MoO3 nanostructures on Au(111)

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MoO{sub 3} is an interesting oxide prototype because its catalytic activity is sensitive to the presence and nature of defects. In this work, we demonstrate that we can control the number of defects in single-layer MoO{sub 3} nanostructures grown on Au(111) by a simple thermal reduction treatment. X-ray photoelectron spectroscopy demonstrates the formation of Mo{sup 5+} species and oxygen vacancies during annealing at 650 K. The percentage of Mo{sup 5+} increases with the duration of annealing, until a stable composition containing 50% Mo{sup 6+} and 50% Mo{sup 5+} is obtained. Surprisingly, the formation of lower oxidation states such as Mo{sup ... continued below

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Deng, X; Quek, S; Biener, M; Biener, J; Kang, D; Schalek, R et al. December 7, 2007.

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MoO{sub 3} is an interesting oxide prototype because its catalytic activity is sensitive to the presence and nature of defects. In this work, we demonstrate that we can control the number of defects in single-layer MoO{sub 3} nanostructures grown on Au(111) by a simple thermal reduction treatment. X-ray photoelectron spectroscopy demonstrates the formation of Mo{sup 5+} species and oxygen vacancies during annealing at 650 K. The percentage of Mo{sup 5+} increases with the duration of annealing, until a stable composition containing 50% Mo{sup 6+} and 50% Mo{sup 5+} is obtained. Surprisingly, the formation of lower oxidation states such as Mo{sup 4+} was not observed. The reduced MoO{sub x} islands remain one layer high, based on scanning tunneling microscope (STM) images. The two-dimensional nature of the reduced oxide nanocrystals may be due to a large barrier for structural reorganization and, thus, may account for the absence of Mo oxidation states lower than +5. Based on scanning tunneling microscopy images and density functional calculations, we propose that the formation of Mo{sup 5+} ions during annealing is not associated with formation of oxygen point defects, but can be attributed to the formation of extended one-dimensional shear defects. These reduced structures are useful for studying the dependence of reactivity on defect type, and present exciting possibilities for chemical sensors and other applications.

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PDF-file: 28 pages; size: 0.7 Mbytes

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  • Journal Name: Surface Science, vol. 602, no. 6, March 15, 2008, pp. 1166-1174; Journal Volume: 602; Journal Issue: 6

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  • Report No.: UCRL-JRNL-237181
  • Grant Number: W-7405-ENG-48
  • Office of Scientific & Technical Information Report Number: 944355
  • Archival Resource Key: ark:/67531/metadc902711

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Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

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  • December 7, 2007

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  • Sept. 27, 2016, 1:39 a.m.

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  • Dec. 9, 2016, 9:42 p.m.

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Deng, X; Quek, S; Biener, M; Biener, J; Kang, D; Schalek, R et al. Selective Thermal Reduction of Single-layer MoO3 nanostructures on Au(111), article, December 7, 2007; Livermore, California. (digital.library.unt.edu/ark:/67531/metadc902711/: accessed November 18, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.