Article

Influence of the Support and the Size of Gold Clusters on Catalytic Activity for Glucose Oxidation

Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
Angewandte Chemie International Edition (Impact Factor: 11.26). 11/2008; 47(48):9265-8. DOI: 10.1002/anie.200802845
Source: PubMed

ABSTRACT

Not all that glitters... The activity of supported gold nanoparticles depends on the method used for their preparation. Gold clusters of about 2 nm in diameter were deposited on nonreducible metal oxides and carbon materials by solid grinding of a volatile organogold complex in a ball mill and subsequent calcination (see scheme). Au/ZrO2 and Au/Al2O3 prepared in this way were extremely efficient catalysts for the aerobic oxidation of glucose. (Chemical Equation Presented).

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    • "Some processes use solid catalysts to resolve these difficulties related to cellulose conversion into glucose [5] [6] [7] [8] [9] [10] [11], chemical precursors [12] [13] [14] [15], and fuel [16] [17] [18]. Reportedly, glucose (and derivatives) can be converted into value-added chemicals such as 5-hydroxymethyl furfural (5-HMF) [17] [19] [20], levulinic acid [17] [21] [22], lactate [23] [24], gluconic acid [25] [26] [27], and hydrocarbons [17,18,28–39], using solid catalysts. Light hydrocarbons are important feedstocks used in petrochemistry, especially C 3 and C 4 olefins are widely used as polymer raw materials. "
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    ABSTRACT: One-pot direct catalytic conversion of cellulose to light hydrocarbon at low temperature (443 K) in the presence of Pt–zeolite catalysts and water was investigated. Results revealed that Pt supported on H+-form ultra stable Y-type (H-USY) zeolite catalyst (Pt/H-USY) enabled direct conversion of cellulose into C3 and C4 hydrocarbons without hydrogen and other expensive reagents. This production trend is attributable to the bifunctional catalysis of supported Pt and acid site in H-USY zeolite, which has a large pore system and effective acidity. Results revealed that the pre-treatment of catalyst was important for selective olefin production. Air-oxidized Pt/H-USY catalyst showed higher olefin selectivity than the catalyst reduced with hydrogen. The Pt/H-USY catalysts showed high stability under the reaction condition. Results suggest that C5 sugars were the reaction intermediate for the C3 hydrocarbons, and C6 sugars were the intermediate for C4 hydrocarbon formation from cellulose over Pt/H-USY catalysts.
    No preview · Article · Jun 2015 · Fuel Processing Technology
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    • "Mechanochemistry, i.e. the induction of chemical reactions through the input of mechanical energy, has a long history in the context of materials processing such as ores and cements as well as in inorganic synthesis. [1] [2] [3] [4] [5] It has more recently been investigated for organic [6], metal–organic synthesis [7] and catalyst preparation. [8] The mechanochemical preparation of catalysts [8] is currently far less developed than the more traditional methods such as wet impregnation. "
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    ABSTRACT: Mechanochemical preparation of Ag/Al2O3 catalysts used for the selective catalytic reduction of NOx using hydrocarbons has been shown to substantially increase the activity of the catalyst in comparison with Ag/Al2O3 prepared by wet impregnation. The effect of using different ball-milling experimental parameters on both the structure of the material as well as the catalyst activity has been investigated and the optimum conditions established. A phase transition from γ- to α-alumina was observed milling at high speeds which was found to result in lower catalyst activities. At lower milling speeds both fracturing and agglomeration of the alumina support can be observed depending on the grinding time. However, due to ball-milling, a general enhancement in the NOx reduction activity was observed for all catalysts compared with the conventionally prepared catalysts irrespective of the reductant used. Transient DRIFTS-MS experiments were performed to investigate the effect of H2 in the absence and presence of water on the SCR reaction over catalysts prepared by both ball milling and wet impregnation. In-situ DRIFTS-MS analysis revealed significant differences in both gas phase and surface species. Most notably, isocyanate species were formed significantly more quickly and at higher surface concentration in the case of the mechanochemically prepared catalyst.
    Full-text · Article · May 2015 · Catalysis Today
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    • "In particular , gold nanoparticles deposited on metal oxide supports exhibit a high catalytic activity towards CO oxidation at low temperatures [12] [15] [16] [18] [19]. Different parameters, such as the size and shape of Au clusters, the nature of the support or the preparation method, play a crucial role in influencing the catalytic activity [14] [19] [22] [23]. "
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    ABSTRACT: This study reports the interaction between metal oxides and gold in acidic media and its effect on the electrochemical oxidation of carbon monoxide. We describe the oxidation of CO in acidic media on Au nanoparticles of 3 and 7 nm on different oxide supports, diamond and carbon electrodes. In addition, the effect of a TiOx support on Au nanoparticles was mimicked by supporting TiOx nanoparticles on bulk gold. The comparison of these two systems strongly suggests that electronic interactions between Au and TiOx, rather than Au nanoparticle size effects, are the driving force of the catalytic activity in Au–TiOx.
    Full-text · Article · Mar 2014 · Journal of Catalysis
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