Surface Sol−Gel Modification of Mesoporous Silica Materials with TiO<sub>2</sub> for the Assembly of Ultrasmall Gold Nanoparticles

Yan, Wenfu; Chen, Bei; Mahurin, Shannon M.; Hagaman, Edward W.; Dai, and Sheng; Overbury, Steven H.

doi:10.1021/jp037713z

Cited by 148 publications

(124 citation statements)

References 43 publications

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“…A layer-by-layer approach was reported by Yan et al [199,200], who modified the surface of mesoporous SBA-15 with TiO 2 via hydrolytic surface sol-gel process, by mixing the SBA-15 with proper amounts of titanium (IV) butoxide in a mixture of anhydrous toluene and anhydrous methanol. After vacuum filtration, washing with anhydrous methanol and vacuum drying, the monolayer of titanium oxide was hydrolyzed with an excess of deionized water.…”

Section: Sio 2 -Based Gold Catalystsmentioning

confidence: 99%

Synthesis of Gold Catalysts Supported on Mesoporous Silica Materials: Recent Developments

2011

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Mesoporous silica materials (MSM) with ordered and controllable porous structure, high surface area, pore volume and thermal stability are very suitable catalyst supports, because they provide high dispersion of metal nanoparticles and facilitate the access of the substrates to the active sites. Since the conventional wet-impregnation and deposition-precipitation methods are not appropriate for the incorporation of gold nanoparticles (AuNPs) into MSM, considerable efforts have been made to develop suitable methods to synthesize Au/MSM catalysts, because the incorporation of AuNPs into the channel system can prevent their agglomeration and leaching. In this review, we summarize the main methods to synthesize active gold catalysts supported on MSM. Examples and details of the preparative methods, as well as selected applications are provided. We expect this article to be interesting to researchers due to the wide variety of chemical reactions that can be catalyzed by gold supported catalysts.

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Section: Sio 2 -Based Gold Catalystsmentioning

confidence: 99%

Synthesis of Gold Catalysts Supported on Mesoporous Silica Materials: Recent Developments

2011

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“…Au/SiO 2 prepared by deposition-precipitation has a low gold loading because, under the basic conditions used to hydrolyze HAuCl 4 to Au(OH) 4 -, the SiO 2 surface is also negatively charged due to the low isoelectric point of SiO 2 (IEP ~2). The negatively charged Au(OH) 4 -species is difficult to adsorb onto the negatively charged SiO 2 , so the catalytic activity of the resulting Au/SiO 2 in CO oxidation is often quite low [66].…”

Section: Au/siomentioning

confidence: 99%

“…Our group modified mesoporous and fumed SiO 2 surfaces with amorphous TiO 2 via a surface-sol-gel technique under non-aqueous conditions (Fig. 6) [66,72]. Ti(OC 4 H 9 ) 4 was used as the precursor to load surface TiO 2 , and methanol and toluene were used as the solvents.…”

Section: Pre-modification Of Sio 2 Supportsmentioning

confidence: 99%

“…Reproduced by permission of the American Chemical Society from Ref. [66] The pre-modification strategy has also been used by others to prepare SiO2-based gold catalysts, such as Au [159,[173][174][175]. Even though the addition of certain promoters can enhance the catalytic activity, most of the resulting catalysts were not particularly active in CO oxidation, presumably because the deposition-precipitation method does not work well for making active Au/SiO 2 catalysts.…”

Section: Figurementioning

confidence: 99%

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Development of novel supported gold catalysts: A materials perspective

2010

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Since Haruta et al. discovered that small gold nanoparticles finely dispersed on certain metal oxide supports can exhibit surprisingly high activity in CO oxidation below room temperature, heterogeneous catalysis by supported gold nanoparticles has attracted tremendous attention. The majority of publications deal with the preparation and characterization of conventional gold catalysts (e.g., Au/TiO 2 ), the use of gold catalysts in various catalytic reactions, as well as elucidation of the nature of the active sites and reaction mechanisms. In this overview, we highlight the development of novel supported gold catalysts from a materials perspective. Examples, mostly from those reported by our group, are given concerning the development of simple gold catalysts with single metal-support interfaces and heterostructured gold catalysts with complicated interfacial structures. Catalysts in the first category include active Au/SiO 2 and Au/metal phosphate catalysts, and those in the second category include catalysts prepared by pre-modification of supports before loading gold, by post-modification of supported gold catalysts, or by simultaneous dispersion of gold and an inorganic component onto a support. CO oxidation has generally been employed as a probe reaction to screen the activities of these catalysts. These novel gold catalysts not only provide possibilities for applied catalysis, but also furnish grounds for fundamental research.

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“…However, the Au/SiO 2 catalysts prepared by the impregnation of SiO 2 with HAuCl 4 or AuCl 3 have relatively large Au particles because the residual chloride ions facilitate the sintering of Au-NPs in the calcination step [14]. Similarly, Au/SiO 2 catalysts prepared by the Dp method have a low catalytic activity in CO oxidation according to the above mentioned explanation [24]. To tackle the above-mentioned problems, we have synthesized a series of Au/MO x (M = Si, Al, Mg, Zn) by means of a colloidal deposition method [25].…”

Section: Synthesis Of Au/sio 2 By Colloidal Depositionmentioning

confidence: 99%

Mesoporous Silica Based Gold Catalysts: Novel Synthesis and Application in Catalytic Oxidation of CO and Volatile Organic Compounds (VOCs)

Pantaleo

Venezia

et al. 2013

Catalysts

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Abstract:Gold nanoparticles, particularly with the particle size of 2-5 nm, have attracted increasing research attention during the past decades due to their surprisingly high activity in CO and volatile organic compounds (VOCs) oxidation at low temperatures. In particular, CO oxidation below room temperature has been extensively studied on gold nanoparticles supported on several oxides (TiO 2 , Fe 2 O 3 , CeO 2 , etc.). Recently, mesoporous silica materials (such as SBA-15, MCM-41, MCM-48 and HMS) possessing ordered channel structures and suitable pore diameters, large internal surface areas, thermal stabilities and excellent mechanical properties, have been investigated as suitable hosts for gold nanoparticles. In this review we highlight the development of novel mesoporous silica based gold catalysts based on examples, mostly from recently reported results. Several synthesis methods are described herein. In detail we report: the modification of silica with organic functional groups; the one-pot synthesis with the incorporation of both gold and coupling agent containing functionality for the synthesis of mesoporous silica; the use of cationic gold complexes; the synthesis of silica in the presence of gold colloids or the dispersion of gold colloids protected by ligands or polymers onto silica; the modification of silica by other metal oxides; other conventional preparation methods to form mesoporous silica based gold catalysts. The gold based catalysts prepared as such demonstrate good OPEN ACCESSCatalysts 2013, 3 775 potential for use in oxidation of CO and VOCs at low temperatures. From the wide family of VOCs, the oxidation of methanol and dimethyldisulfide has been addressed in the present review.

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Surface Sol−Gel Modification of Mesoporous Silica Materials with TiO₂ for the Assembly of Ultrasmall Gold Nanoparticles

Cited by 148 publications

References 43 publications

Synthesis of Gold Catalysts Supported on Mesoporous Silica Materials: Recent Developments

Synthesis of Gold Catalysts Supported on Mesoporous Silica Materials: Recent Developments

Development of novel supported gold catalysts: A materials perspective

Mesoporous Silica Based Gold Catalysts: Novel Synthesis and Application in Catalytic Oxidation of CO and Volatile Organic Compounds (VOCs)

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Surface Sol−Gel Modification of Mesoporous Silica Materials with TiO2 for the Assembly of Ultrasmall Gold Nanoparticles

Cited by 148 publications

References 43 publications

Synthesis of Gold Catalysts Supported on Mesoporous Silica Materials: Recent Developments

Synthesis of Gold Catalysts Supported on Mesoporous Silica Materials: Recent Developments

Development of novel supported gold catalysts: A materials perspective

Mesoporous Silica Based Gold Catalysts: Novel Synthesis and Application in Catalytic Oxidation of CO and Volatile Organic Compounds (VOCs)

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Surface Sol−Gel Modification of Mesoporous Silica Materials with TiO₂ for the Assembly of Ultrasmall Gold Nanoparticles