On the Synergetic Catalytic Effect in Heterogeneous Nanocomposite Catalysts

Shi, Jianlin

doi:10.1021/cr3002752

Cited by 593 publications

(482 citation statements)

References 370 publications

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“…It could be understood on the basis of the very high flexibility of the microemulsion film (see experiments 25,27,28). However, even using a rigid film (experiments 24,26,29,32) no experimental evidence of a segregated structure was obtained. The key parameter to understand these results is the metal salts concentration.…”

Section: Changing Concentrationmentioning

confidence: 99%

On Metal Segregation of Bimetallic Nanocatalysts Prepared by a One-Pot Method in Microemulsions

2017

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A comparative study on different bimetallic nanocatalysts prepared from microemulsions using a one-pot method has been carried out. The analysis of experimental observations, complemented by simulation studies, provides detailed insight into the factors affecting nanoparticle architecture: (1) The metal segregation in a bimetallic nanocatalysts is the result of the combination of three main kinetic parameters: the reduction rate of metal precursors (related to reduction standard potentials), the material intermicellar exchange rate (determined by microemulsion composition), and the metal precursors concentration; (2) A minimum difference between the reduction standard potentials of the two metals of 0.20 V is needed to obtain a core-shell structure. For values ∆ε 0 smaller than 0.20 V the obtaining of alloys cannot be avoided, neither by changing the microemulsion nor by increasing metal concentration; (3) As a rule, the higher the film flexibility around the micelles, the higher the degree of mixture in the nanocatalyst; (4) A minimum concentration of metal precursors is required to get a core-shell structure. This minimum concentration depends on the microemulsion flexibility and on the difference in reduction rates.

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Section: Changing Concentrationmentioning

confidence: 99%

On Metal Segregation of Bimetallic Nanocatalysts Prepared by a One-Pot Method in Microemulsions

2017

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“…The recent progress in heterogeneous catalysis by gold resulted in remarkable investigations that demonstrated the high activity of 3-10-nm gold particles in the conversion of bioethanol to synthetic hydrocarbons [2], water gas shift reaction [3,4], selective hydrogenation of alkynes [5][6][7][8], hydrodechlorination of organic molecules [9,10], and CO oxidation [11][12][13]. Numerous data on gold catalysis indicate that, apart from the critical particle size (3-5 nm) [1,14], significant roles for catalytic activity are played by particle shape [13,15], particle surface chemistry [16,17], the support nature [10,18], mutual arrangement of particles, the sign and quantity of the electric charge on the nanoparticle surface [19,20]. However, the activity of gold nanoparticles is mainly attributed to the high surface curvature [1,13].…”

Section: Introductionmentioning

confidence: 99%

Application of Au–Cu nanowires fabricated by laser ablation in superfluid helium as catalysts for CO oxidation

et al. 2015

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The copper-doped gold nanowires (4 nm in diameter) were produced by the novel technique based of laser ablation of Au-Cu alloy inside superfluid helium. The principle of the method is using the quantized vortices as the 1D template for the condensation of the ablation products into thin threads. The nanowires were applied as the catalyst in СО oxidation with oxygen. The activity of Au-Cu nanowires deposited on glass filters was compared with that for monometallic and bimetallic Au and Cu particles (3-8 nm in diameter) deposited on alumina by traditional deposition-precipitation and impregnation techniques. The apparent activation energies of the reaction (Еа) were 95 and 98, 150, and 147 kJ/ mol for Au-Cu nanowires and Au-Cu, Au, and Cu particles, respectively. During running-in of the Au-Cu nanowirebased catalyst, Еа decreased to 20 kJ/mol and retained at this level in the subsequent cycles of lowering and raising the reactor temperature.

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“…Aluminosilicate zeolites and zeolitic metallosilicate containing isolated transition metal ions have been extensively used as solid Brønsted acid catalysts in petrochemical processing and solid Lewis acid catalysts for redox reactions, thanks to their uniform, small pore size, flexible frameworks, and controlled chemistry [51][52][53]. However, their applications are limited to small molecules that can diffuse through the small cavities (<1.5 nm typically) and the narrow channels (<0.8 nm) between the cavities [54].…”

Section: Sn-containing Mesoporous Materials Catalystsmentioning

confidence: 99%

Sn-based catalysts for Baeyer-Villiger oxidations by using hydrogen peroxide as oxidant

Cui

Shi

2016

Sci. China Mater.

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Baeyer-Villiger (BV) oxidation is one of the most important transformation reactions in synthetic organic chemistry. Catalytic versions of the BV oxidation are particularly attractive in practical applications, because the catalytic transformation substantially simplifies reaction process while minimizing reactant consumption as well as waste production. Further benefits are expected from replacing peracids, the traditionally used oxidant, by low cost and environmentally friendly hydrogen peroxide (H2O2). This review will first introduce very briefly the features of BV oxidation reactions, and the corresponding oxidants traditionally used. Afterwards, the emphasis will be placed on the specific Sn-based catalysts, their performance comparison for the BV oxidation reaction by using H2O2 as oxidant, and the catalytic mechanisms of most Sn-based catalysts reported so far, including homogeneous Sn-based catalysts (such as Sn-based fluorous biphase system catalysts), heterogeneous Sn-based catalysts (such as Sn-based zeolite catalysts, Sn-based mesoporous composites, Sn-incorporated clay catalysts, Sn-based metal oxide composites and polymer supported Sn catalysts). Finally, the Sn-based catalysts for BV oxidation are outlooked for their potentials and perspectives in enhancing the performance and then accelerating the practical applications of BV oxidations by using H2O2. The developing direction of the Sn-based catalytic BV reaction is also illustrated.

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On the Synergetic Catalytic Effect in Heterogeneous Nanocomposite Catalysts

Cited by 593 publications

References 370 publications

On Metal Segregation of Bimetallic Nanocatalysts Prepared by a One-Pot Method in Microemulsions

On Metal Segregation of Bimetallic Nanocatalysts Prepared by a One-Pot Method in Microemulsions

Application of Au–Cu nanowires fabricated by laser ablation in superfluid helium as catalysts for CO oxidation

Sn-based catalysts for Baeyer-Villiger oxidations by using hydrogen peroxide as oxidant

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