Highly active gold-ceria catalyst for the room temperature oxidation of carbon monoxide

Pillai, Unnikrishnan R.; Deevi, S.C.

doi:10.1016/j.apcata.2005.10.040

Cited by 112 publications

(56 citation statements)

References 31 publications

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“…In such a case, the use of alternative methods to determine the metallic particle size can be helpful to support the TEM characterizations, where the CO and H 2 chemisorptions are highly recommended to be performed on select metals. The CO adsorption has been frequently used to determine the metallic particle size of noble metals; even on gold supported catalysts [14]; however, as far as we know, the hydrogen chemisorption has not been reported as a technique to determine the particle size on gold supported catalysts. In this work we proposed to carry out both the CO and H 2 chemisorptions; and the comparison of the particle size obtained by these methods with those obtained by TEM.…”

Section: Introductionmentioning

confidence: 99%

Gold Particle Size Determination on Au/TiO2-CeO2 Catalysts by Means of Carbon Monoxide, Hydrogen Chemisorption and Transmission Electron Microscopy

Guzmán

Angel

Gómez³

et al. 2009

JNanoR

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Au/TiO 2 and Au/TiO 2 -CeO 2 catalysts were prepared by the sol-gel method and carbon monoxide, hydrogen chemisorption and TEM spectroscopy have been exploited to determine the size of gold particles. The gold nanoparticles (8.1 to 2.1 nm) were deposited by using the deposition-precipitation method. The XRD characterization shows the presence of anatase as the TiO 2 crystalline phase; while by XPS spectroscopy, the presence of Au°, Au 2 O 3 , Ce 3+ and Ce 4+ species co-existing in the Au/TiO 2 -CeO 2 catalysts is shown. The characterizations by TPD-CO as well as by TPD-H 2 (temperature programmed desorption) showed that on catalysts containing cerium, the gold particle size can be determined with great accuracy by using these chemisorption methods. The gold particle size calculated from either the CO or H 2 thermodesorption values is in good agreement with that obtained by High Resolution Transmission Electron Microscopy (HRTEM) and Scanning Transmission Electron Microscopy (STEM) analyses. It was proposed that the TPD-CO and/or TPD-H 2 techniques could be helpful for the characterization of the gold particles by TEM; especially when the high contrast in the pictures of the supports containing CeO 2 prevents the particle size from being determined.

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Section: Introductionmentioning

confidence: 99%

Gold Particle Size Determination on Au/TiO2-CeO2 Catalysts by Means of Carbon Monoxide, Hydrogen Chemisorption and Transmission Electron Microscopy

Guzmán

Angel

Gómez³

et al. 2009

JNanoR

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“…can considerably influence the catalytic properties of gold clusters and modify (enhance or suppress) their reactivity. 2,9,12,17 Such supports usually stabilize gold particles and can modify considerably their geometric structure and morphology, [18][19][20][21][22] which in turn can affect catalytic properties of the supported particles. Charge transfer from the metal oxide support to the a) On gold results in formation of the highly reactive charged gold clusters.…”

Section: Introductionmentioning

confidence: 99%

CO oxidation on h-BN supported Au atom

Gao

Lyalin

Taketsugu

2013

The Journal of Chemical Physics

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The mechanism of CO oxidation by O 2 on Au atoms supported on the pristine and defected hexagonal boron nitride (h-BN) surface has been studied theoretically using density functional theory. It is found that O 2 binds stronger than CO on an Au atom supported on the defect free h-BN surface and h-BN surface with nitrogen vacancy (V N @h-BN), but weaker than CO on a free Au atom or Au trapped by a boron vacancy (V B @h-BN). The excess of the positive or negative charge on Au can considerably change its catalytic properties and enhance activation of the adsorbed O 2 . Coadsorption of CO and O 2 on Au, Au/V N @h-BN, and Au/V B @h-BN results in additional charge transfer to O 2 . Various pathways of the CO oxidation reaction by molecular oxygen are studied. We found two different pathways for CO oxidation: a two-step pathway where two CO 2 molecules are formed independently, and a self-promotion pathway where oxidation of the first CO molecule is promoted by the second CO molecule. Interaction of Au with the defect-free and defected h-BN surface considerably affects the CO oxidation reaction pathways and barriers. Therefore, Au supported on the h-BN surface (pristine or defected) cannot be considered as pseudo-free atom and support effects have to be taken into account, even when the interaction of Au with the support is weak.

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“…The nature of the active species in highly dispersed Au catalysts (ionic vs metallic, low-coordinated surface atoms vs metal/support interface) is a matter of extensive debates. Among many gold catalysts reported in the literature, those supported on the cerium oxide (CeO 2 ) often show a superior activity ( [2][3][4][5][6][7][8][9], and references therein). It should be mentioned that the reaction mechanisms, involving cationic Au 3+ and Au + species as the most active, have been reinforced after experimental observations by Flutzani-Staphanopolus and co-workers on the Au/CeO 2 catalysts [10].…”

Section: Introductionmentioning

confidence: 99%

Gold supported on well-ordered ceria films: nucleation, growth and morphology in CO oxidation reaction

et al. 2007

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Abstract. Structure of gold nanoparticles formed by physical vapor deposition onto thin ceria films was studied by scanning tunneling microscopy (STM). Gold preferentially nucleates on point defects present on the terraces of the well-ordered, fully oxidized films to a low density. The nucleation expands to the terrace step edges, providing a large variety of low-coordinated sites. Only at high coverage, the Au particles grow homogeneously on the oxygen-terminated CeO 2 (111) terraces. The morphology of Au particles was further examined by STM in situ and ex situ at elevated (up to 20 mbar) pressures of O 2 , CO, and CO + O 2 at 300 K. The particles are found to be stable in O 2 ambient up to 10 mbar, meanwhile gold sintering emerges at CO pressures above ~ 1 mbar. Sintering of the Au particles, which mainly proceeds along the step edges of the CeO 2 (111) support, is observed in CO + O 2 (1:1) mixture at much lower pressure (~10 -3 mbar), thus indicating that the structural stability of the Au/ceria catalysts is intimately connected with its reactivity in the CO oxidation reaction.

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Highly active gold-ceria catalyst for the room temperature oxidation of carbon monoxide

Cited by 112 publications

References 31 publications

Gold Particle Size Determination on Au/TiO<sub>2</sub>-CeO<sub>2</sub> Catalysts by Means of Carbon Monoxide, Hydrogen Chemisorption and Transmission Electron Microscopy

Gold Particle Size Determination on Au/TiO<sub>2</sub>-CeO<sub>2</sub> Catalysts by Means of Carbon Monoxide, Hydrogen Chemisorption and Transmission Electron Microscopy

CO oxidation on h-BN supported Au atom

Gold supported on well-ordered ceria films: nucleation, growth and morphology in CO oxidation reaction

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