Synthesis, characterization, and catalytic application of highly ordered mesoporous alumina-carbon nanocomposites

Xu, Jinming; Wang, Aiqin; Wang, Xiaodong; Zhang, Tao

doi:10.1007/s12274-010-0038-0

Cited by 34 publications

(25 citation statements)

References 35 publications

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“…A total TON of Pt for the formation of sorbitol and mannitol was 95 175 in these reactions. In another way, Zhang et al proposed an ordered mesoporous -Al 2 O 3 -C composite for the catalyst support affording both good interaction between Pt and Al 2 O 3 and watertolerant property derived from C. 22 The -Al 2 O 3 phase in the composite was thermally more stable than usual -Al 2 O 3 , but the 100 reusability was not mentioned. A kinetic study of the Pt(N)/BP2000-catalysed reaction indicated that this reaction consists of two steps: the hydrolysis of cellulose to glucose via water-soluble oligosaccharides and the hydrogenation of glucose to sorbitol as expected.…”

Section: Optimisation Of the Catalytic Systemmentioning

confidence: 99%

Conversion of lignocellulose into renewable chemicals by heterogeneous catalysis

Kobayashi

Ohta

Fukuoka

2012

Catal. Sci. Technol.

191

121

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Conversion of lignocellulose into renewable chemicals and fuels has received great attention for building up the sustainable societies. However, the utilisation of lignocellulose in the chemical industry has almost been limited for paper manufacturing because of the complicated chemical structure and persistent property of lignocellulose. Heterogeneous catalysis has the potential to selectively convert lignocellulosic biomasses into various useful chemicals, and this methodology has rapidly progressed in the last several 10 years. In this perspective article, we outline our recent approaches on the heterogeneous catalysis for this challenging subject with related literatures. Lignocellulose as a renewable resourceConversion of biomass to renewable fuels and chemicals has attracted significant attention as a key technology for the 15 sustainable societies.1 Lignocellulose is the most abundant biomass resource, produced together with sugars and starch from carbon dioxide and water via the photosynthesis using sunlight and successive metabolism in plants. Lignocellulose is not digestible for human beings, which is an advantage over sugars 20 and starch since the use of edible carbohydrates for the synthesis of bioethanol fuel has competed with the food production, giving us a consensus that we should use non-food biomass as a feedstock to fuels and chemicals. Therefore, lignocellulose is one of the most attractive biomass resources in nature. 25Lignocellulose in woods consists of cellulose (40-50%), hemicellulose (20-40%) and lignin (20-30%).2 Cellulose is a water-insoluble polymer composed of glucose linked by -1,4-glycosidic bonds ( Fig. 1(a)) and forms robust crystal structures with inter-and intra-molecular hydrogen bonds, possessing high 30 chemical stability. 3 Hemicellulose is also a polysaccharide, but

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Section: Optimisation Of the Catalytic Systemmentioning

confidence: 99%

Conversion of lignocellulose into renewable chemicals by heterogeneous catalysis

Kobayashi

Ohta

Fukuoka

2012

Catal. Sci. Technol.

191

121

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“…The mesoporous niobia synthesized without resol after calcination are composed of large particles with disordered structures (Figure S3), further suggesting that the resol assistance is crucial for the formation of an ordered Nb 2 O 5 mesostructure. Although previous work shows that mesoporous carbon-TiO 2 , carbon-Al 2 O 3 , and carbon-WO 3 composites [46][47][48] can be synthesized by using resol as the carbon source and block copolymer as the templates, they failed to convert into the corresponding mesoporous metal oxides because of structure collapse during calcination.…”

Section: Methodsmentioning

confidence: 99%

A Resol‐Assisted Co‐Assembly Approach to Crystalline Mesoporous Niobia Spheres for Electrochemical Biosensing

Luo

Dong

et al. 2013

Angewandte Chemie

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Ordered mesoporous materials have attracted considerable attention owing to their distinctive properties and great potential for applications in catalysis, [1][2][3][4][5] adsorption, [6][7][8] separation, [9,10] electrochemistry, [11][12][13][14][15] sensors, [16][17][18][19] and drug delivery. [20][21][22][23] As an important transition-metal oxide, niobium oxide is attracting more and more attention owing to its unique catalytic and electronic properties and applications in catalysis, sensing, electronic, and magnetic devices. [24][25][26][27][28] Design and synthesis of ordered mesoporous niobium oxides are important to improve their application performances, because the uniform and well-connected mesopores can facilitate the diffusion of guest molecules within frameworks and the high surface areas can offer abundant accessible active sites. Solvent-evaporation-induced self-assembly (EISA) has been employed to synthesize various ordered mesoporous metal oxides by using various amphiphilic organic molecules as the template. [29][30][31][32][33][34][35][36][37][38] However, most of the mesoporous niobium oxides reported to date suffered some problems, including limited small pore size, low ordering of mesostructure, and unstable framework with low crystallinity. Interestingly, by using poly(isoprene-block-ethylene oxide) with highmolecular weight (ca. 33500 g mol À1 ) as the template, Lee et al. recently have developed a combined assembly by soft and hard (CASH) method for synthesis of ordered mesoporous niobia with crystalline frameworks. [39] Similar to the typical EISA approach, the CASH method is sensitive to synthesis condition, and a slight fluctuation of environmental humidity can affect co-assembly process, resulting in poorly ordered mesostructures. Additionally, the EISA approach usually only leads to film-like or monolithic mesoporous materials that have unfavorable pore orientation (e.g. mesopores running parallel to their surface), limited pore connection and accessibility, thus impeding their applications in catalysis and sensor. Therefore, the exploration of new synthetic strategy for a facile and controllable synthesis of ordered mesoporous metal oxides with unique pore orientation is of high importance and great interest.As a synthetic polymer oligomer, resol is soluble in most polar solvents (e.g. water, ethanol, THF) and has multiple phenolic hydroxy groups. It can self-polymerize into rigid phenolic formaldehyde (PF) resin upon heating. Resol has been used as good building block to co-assemble with amphiphilic block copolymers (e.g. Pluronic copolymers) by hydrogen bonding without strictly controlling over the synthetic conditions (e.g. solvent, humidity, solvent evaporation rate), [40][41][42][43] giving rise to ordered mesoporous PF resins, and even ordered mesoporous carbons after a further pyrolysis in inert atmospheres. Inspired by the unique properties of resol, we herein demonstrate a facile resol-assisted solvent evaporation induced self-assembly (RA-EISA) to synthesize ordered mesop...

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“…It has previously been shown that the addition of inorganic components to the carbon framework suppresses the microporosity of the material. [29] The physical properties of catalysts prepared by impregnation of 15 wt. % Co on different supports are shown in Table 1.…”

Section: Characterization Of Catalystsmentioning

confidence: 99%

“…It has been reported that the existence of oxygen-containing functional groups on the carbon support encourages the dispersion and stability of metal catalysts. [33] The 29 Si magic angle spinning (MAS) NMR spectrum of representative mesoporous carbon-silica sample C-Si(28) shows a broad signal at d = À110 ppm, which is attributed to the chemical shift of Q 4 species, indicating the more completely cross-linked framework, [OSiÀO] as shown in Figure 3. These results imply a relatively complex chemical environment around silica, with the possibility of some interaction with the carbon species.…”

Section: Characterization Of Catalystsmentioning

confidence: 99%

Fischer–Tropsch Synthesis Over Cobalt Supported On Silica‐Incorporated Mesoporous Carbon

et al. 2013

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The influence of carbon–silica hybrid supports on cobalt catalysts in Fischer–Tropsch synthesishas been investigated. Mesoporous carbon–silica hybrid supports were synthesized through a hydrogen‐bonding‐assisted self‐assembly route by loading different amounts of silica (0 to 45 %) as a framework composition with mesoporous carbon. These carbon and hybrid supports were then impregnated with 15 wt. % cobalt and the resulting catalysts were characterized by various physicochemical, gravimetric, and spectroscopic methods. The dispersion of silica in the framework of mesoporous carbon modified the surface chemistry and enhanced the wetting properties of the support. Hence, the dispersion and reducibility of cobalt over the hybrid supports increased compared to those of the carbon‐supported catalyst. However, above the optimum silica incorporation of 34 %, the possibility of phase separation and structural transformation of silica at the high carbonization temperature decreased the dispersion and reducibility of the supported Co catalysts. The carbon‐supported catalyst showed a quick drop in the activity during the initial stages of the reaction due to the migration of cobalt particles over the hydrophobic and inert support surface. On the contrary, carbon–silica hybrid supports inhibited the mobility of cobalt particles and produced a higher density of active Co0 sites, leading to a higher initial activity. Carbon–silica‐supported catalysts with a silica content of up to 34 % were found to exhibit excellent steady state Fischer–Tropsch synthesis activity and C5+ selectivity compared to only carbon and carbon–silica‐supported catalyst with >34 % silica incorporation.

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Synthesis, characterization, and catalytic application of highly ordered mesoporous alumina-carbon nanocomposites

Cited by 34 publications

References 35 publications

Conversion of lignocellulose into renewable chemicals by heterogeneous catalysis

Conversion of lignocellulose into renewable chemicals by heterogeneous catalysis

A Resol‐Assisted Co‐Assembly Approach to Crystalline Mesoporous Niobia Spheres for Electrochemical Biosensing

Fischer–Tropsch Synthesis Over Cobalt Supported On Silica‐Incorporated Mesoporous Carbon

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