Influence of the crystalline phase and surface area of the TiO2 support on the CO oxidation activity of mesoporous Au/TiO2 catalysts

Denkwitz, Y.; Makosch, Martin; Geserick, Jasmin; Hörmann, U.; Selve, Sören; Kaiser, Ute; Hüsing, Nicola; Behm, R. J.

doi:10.1016/j.apcatb.2009.06.016

Cited by 47 publications

(41 citation statements)

References 50 publications

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“…7), which had the best absorption in the visible region among all samples, suggesting that the shifts alone into the visible region cannot assure the photocatalytic enhancements. This can be explained by formation of silver clusters in terms of their migration and combination [20].…”

Section: Photocatalytic Performancementioning

confidence: 99%

Silver doping on TiO2 nanoparticles using a sacrificial acid and its photocatalytic performance under medium pressure mercury UV lamp

Pipelzadeh

Babaluo

Haghighi

et al. 2009

Chemical Engineering Journal

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Section: Photocatalytic Performancementioning

confidence: 99%

Silver doping on TiO2 nanoparticles using a sacrificial acid and its photocatalytic performance under medium pressure mercury UV lamp

Pipelzadeh

Babaluo

Haghighi

et al. 2009

Chemical Engineering Journal

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“…Since the pioneering work on CO oxidation over supported Au catalysts by Haruta et al in the mid-80s, the situation has changed and numerous investigations have been aimed at understanding catalyst synthesis and mechanisms involved in Au catalysis. It has been shown that gold nanoparticles with sizes below 5 nm supported on metal oxide substrates (e.g., TiO 2 , Fe 2 O 3 , Co 3 O 4 , Al 2 O 3 , SiO 2 ) exhibit unique catalytic properties for CO oxidation [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], water-gas shift [21][22][23][24][25][26], and epoxidation of propylene [27][28][29][30][31]. In particular, Au/TiO 2 exhibits CO oxidation activity at temperatures as low as 90 K. Recent studies have reported that Ag nanoparticles supported on TiO 2 are similar to Au nanoparticles supported on TiO 2 for some reactions [32,33].…”

Section: Introductionmentioning

confidence: 99%

Physico-Chemical Effects on the Scale-Up of Ag Photodeposition on TiO2 Nanoparticles

Chan

Barteau

2011

Top Catal

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We have previously demonstrated that TiO 2 nanoparticles can be functionalized by photodeposition with silver or gold particles in the 1-2 nm range presumed to be desirable for catalysis applications. However, the preparation of these samples directly on microscope grids, while conducive to particle size determinations, did not produce sufficient materials for reaction studies. We report here scale-up techniques designed to produce greater quantities of material for testing, while maintaining characteristics that contribute to uniformity in the deposition process. For the scale-up process, an irradiation source with highly uniform intensity is necessary to generate Ag/TiO 2 samples with consistent Ag loading. In addition, control of the precursor concentration is also required to produce Ag/ TiO 2 samples with high Ag loading and narrow Ag size distribution. The optimum conditions for the scale-up process found in this study involved Ag photodeposition from a 5 9 10 -3 M AgNO 3 solution using a high pressure Hg lamp at 366 nm for 60 s. Under these reaction conditions, the size of Ag particles determined by TEM and HAADF-STEM imaging was within 1-2 nm and the Ag loading was *3.2 wt%. Achievement of this level of uniformity required control of the uniformity of illumination, as well as of the solution concentration and irradiation conditions. Higher solution concentrations and higher power led to the growth of larger (ca. 10 nm) silver particles. In contrast, the loading and size distribution of the Ag particles photodeposited were remarkably insensitive to the source and morphology of the TiO 2 nanoparticles utilized. No Ag peak was resolved in the XRD patterns for Ag/TiO 2 samples obtained from the optimized scale-up process, corroborating the size range determination of the Ag nanoparticles. XPS showed that the Ag particles in all cases were metallic Ag.

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“…In addition to properties such as Au particle size, choice of support and preparation method, the nature of the supporting oxide has a significant effect on the activity of these catalysts. Catalytic testing of Au supported on different phases of titania has been demonstrated to show relatively similar activity with respect to CO oxidation [17][18][19]. Comparative studies performed by Comotti et al [18] on porous and non-porous Au/TiO 2 catalysts prepared from different crystalline phases of TiO 2 conclude that the crystalline phase had no significant influence on the catalytic properties of the unconditioned catalysts.…”

Section: Introductionmentioning

confidence: 95%

Effect of Pretreatment on Carbon-Supported Au/TiO2 Catalysts for Preferential Oxidation of CO

et al. 2011

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The impact of thermal treatment at various preparation stages of carbon supported Au/TiO 2 catalysts prior to oxidation of CO in the presence and absence of hydrogen was studied. An increase in catalytic activity for thermally treated samples due to a more ordered structure of TiO 2 was observed. A reversible deactivation of the catalysts occurred in the absence of hydrogen. However, the activity was restored at preferential CO oxidation conditions in presence of hydrogen.

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Influence of the crystalline phase and surface area of the TiO2 support on the CO oxidation activity of mesoporous Au/TiO2 catalysts

Cited by 47 publications

References 50 publications

Silver doping on TiO2 nanoparticles using a sacrificial acid and its photocatalytic performance under medium pressure mercury UV lamp

Silver doping on TiO2 nanoparticles using a sacrificial acid and its photocatalytic performance under medium pressure mercury UV lamp

Physico-Chemical Effects on the Scale-Up of Ag Photodeposition on TiO2 Nanoparticles

Effect of Pretreatment on Carbon-Supported Au/TiO2 Catalysts for Preferential Oxidation of CO

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