Evaluation of the Au size effect: CO oxidation catalyzed by Au/TiO2

Overbury, Steven H.; Schwartz, Viviane; Mullins, David R.; Yan, Wenfu; Dai, Sheng

doi:10.1016/j.jcat.2006.04.018

Cited by 242 publications

(179 citation statements)

References 28 publications

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“…Similarly, the optimal Au size for CO oxidation was reported to be 3 nm (158,159). A series of Au/TiO 2 catalysts with different gold sizes was prepared by a sequence of calcination steps and studied in CO oxidation (160). For Au particles with mean particle size, d, in the range of 2-10 nm, the measured TOF at 298 K varied as d 21.7 ¡ 0.2 and d 20.9 ¡ 0.2 for the 7.2 and 4.5 wt% Au/ TiO 2 catalysts, respectively.…”

Section: Co Oxidationmentioning

confidence: 99%

Recent Advances in the Liquid‐Phase Synthesis of Metal Nanostructures with Controlled Shape and Size for Catalysis

2009

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Section: Co Oxidationmentioning

confidence: 99%

Recent Advances in the Liquid‐Phase Synthesis of Metal Nanostructures with Controlled Shape and Size for Catalysis

2009

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“…For example, Gates and co-workers use X-ray absorption techniques (XANES, EXAFS) and infrared spectroscopy to monitor the oxidation states of Au in CO oxidation and ethylene hydrogenation reactions over Au/MgO [16]. A similar approach has been recently used by Kung and co-workers [17] for studies of the CO oxidation reaction over Au/TiO 2 , by Wang et al [18] on Au/CeO 2 catalysts for water gas-shift reaction, Overbury et al [19] on Au/TiO 2 catalysts of CO oxidation and Wieher et al [20] of different gold catalysts. A recent paper by Hutchings et al [21] reports on complementary studies performed in different groups on the same Au/Fe 2 O 3 catalysts, in particular showing good potentia ls for using Au 197 Mössbauer spectroscopy to elucidate the role of cationic species in reactions.…”

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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“…Gold nanoparticles supported on metal oxides can indeed catalyze low-temperature complete oxidation of hydrocarbons and CO, but also epoxidation reactions and hydrogenations, the NO reduction, and several other reactions as has been reviewed in the recent literature [2,3]. Perhaps the most intensively studied reaction to date is the CO oxidation on gold supported on oxides, such as iron oxide and titania [1,[4][5][6][7], and ceria [8][9][10][11], but also on non-reducible oxides, such as alumina [12][13][14][15] and silica [12]. Activity of nanoparticles of gold on non-oxide supports has also been reported [16].…”

Section: Introductionmentioning

confidence: 99%

Comparison of the activity of Au/CeO2 and Au/Fe2O3 catalysts for the CO oxidation and the water-gas shift reactions

et al. 2007

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We compare the activity and relevant gold species of nanostructured gold-cerium oxide and gold-iron oxide catalysts for the CO oxidation by dioxygen and water. Well dispersed gold nanoparticles in reduced form provide the active sites for the CO oxidation reaction on both oxide supports. On the other hand, oxidized gold species, strongly bound on the support catalyze the water-gas shift reaction. Gold species weakly bound to ceria (doped with lanthana) or iron oxide can be removed by sodium cyanide at pH ‡12. Both parent and leached catalysts were investigated. The activity of the leached gold-iron oxide catalyst in CO oxidation is approximately two orders of magnitude lower than that of the parent material. However, after exposure to H 2 up to 400°C gold diffuses out and is in reduced form on the surface, a process accompanied by a dramatic enhancement of the CO oxidation activity. Similar results were found with the gold-ceria catalysts. On the other hand, pre-reduction of the calcined leached catalyst samples did not promote their water-gas shift activity. UV-Vis, XANES and XPS were used to probe the oxidation state of the catalysts after various treatments.

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Evaluation of the Au size effect: CO oxidation catalyzed by Au/TiO2

Cited by 242 publications

References 28 publications

Recent Advances in the Liquid‐Phase Synthesis of Metal Nanostructures with Controlled Shape and Size for Catalysis

Recent Advances in the Liquid‐Phase Synthesis of Metal Nanostructures with Controlled Shape and Size for Catalysis

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

Comparison of the activity of Au/CeO2 and Au/Fe2O3 catalysts for the CO oxidation and the water-gas shift reactions

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