Preparation of stable mesoporous inorganic oxides via nano-replication technique

Kang, Min Suk; Kim, Dongchan; Yi, Seung-Hwan; Han, Jae Uk; Yie, Jae Eui; Kim, Ji Man

doi:10.1016/j.cattod.2004.06.063

Cited by 61 publications

(42 citation statements)

References 16 publications

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“…The average crystallite size is 7.7 nm. The WZ and Pd/WZ samples are predominantly tetragonal and contain a randomly distributed mesoporous phase, which is evident by the peak at 2θ = 1.8 • [37]. This peak became lower in intensity and somewhat broader after the introduction of palladium indicating an increase in the pore size distribution relative to the WZ sample.…”

Section: Ft-ir Spectroscopymentioning

confidence: 96%

Routes of formation and composition of NOx complexes adsorbed on palladium-promoted tungstated zirconia

Kantcheva

Çayırtepe

2006

Journal of Molecular Catalysis A: Chemical

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Surface species obtained during the adsorption of NO and NO/O 2 coadsorption at room temperature on Pd-free (WZ) and Pd-promoted tungstated zirconia (Pd/WZ) are identified by means of in situ FT-IR spectroscopy. The WZ and Pd/WZ samples have a tetragonal structure and contain randomly distributed mesoporous phase. Dispersed palladium(II) species are present in two different environments: (i) Pd 2+ ions, which have only Zr 4+ ions in their second coordination sphere and (ii) Pd 2+ ions, which are linked to both zirconium and tungsten ions via oxygen bridges. On the Pd/WZ sample, NO undergoes oxidation to various NO x species depending on the temperature. The compounds formed at room-temperature oxidation are adsorbed N 2 O 3 and products of its self-ionization, NO + and NO 2 − . In this process W(VI) is involved, being reduced to W(IV). At high temperature N 2 O 3 decomposes, restoring the W O species. Under these conditions, NO undergoes oxidation to NO 2 by the Pd(II) ions, which are reduced to Pd(I). The nitrosyls of Pd(I) display high thermal stability and do not disappear upon evacuation at 623 K. During NO/O 2 coadsorption on the Pd/WZ catalyst at room temperature, the amounts of surface nitrates and NO 2 /N 2 O 4 formed in the gas phase are significantly lower than those observed under identical conditions in the presence of tungstated zirconia. It is concluded that promotion of tungstated zirconia with palladium(II) suppresses the oxidation of NO by molecular oxygen at room temperature due to the elimination of acidic protons involved in the process.

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Section: Ft-ir Spectroscopymentioning

confidence: 96%

Routes of formation and composition of NOx complexes adsorbed on palladium-promoted tungstated zirconia

Kantcheva

Çayırtepe

2006

Journal of Molecular Catalysis A: Chemical

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“…Recently, porous metal oxides, such as Al 2 O 3 , TiO 2 , ZrO 2 , V 2 O 5 , etc., with high thermal stabilities as well as crystalline frameworks were prepared via the above nanocasting technique. [110] However, characterization of the materials showed that, although some of the structural features of the parent templates could be transferred to the casts, the degree of structural order was appreciably lower than in the parent materials. A catalytically quite interesting material is ZnO, since it is a major component in catalysts for methanol synthesis and methanol steam reforming.…”

Section: Carbon As the Templatementioning

confidence: 98%

Nanocasting: A Versatile Strategy for Creating Nanostructured Porous Materials

2006

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Nanocasting is a powerful method for creating materials that are more difficult to synthesize by conventional processes. We summarize recent developments in the synthesis of various structured porous solids, covering silica, carbon, and other nonsiliceous solids that are created by a nanocasting pathway. Structure replication on the nanometer length scale allows materials' properties to be manipulated in a controlled manner, such as tunable composition, controllable structure and morphology, and specific functionality. The nanocasting pathway with hard templates opens the door to the design of highly porous solids with multifunctional properties and interesting application perspectives.

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“…Therefore, it is necessary to find a new route to prepare high surface area copper-chromite catalysts. The recently reported carbon template method has been shown to be successful for synthesis of zeolite, metals, and oxides with high surface area [17][18][19][20][21][22][23][24]. The method allowed an effective control of the particle size of the resulting materials by adjusting the conditions of synthesis.…”

Section: Introductionmentioning

confidence: 98%

Template Preparation of Highly Active and Selective Cu–Cr Catalysts with High Surface Area for Glycerol Hydrogenolysis

Liang

Ding

et al. 2009

Catal Lett

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High surface area Cu-Cr catalysts had been prepared via a facile carbon template route, and characterized by N 2 physisorption, temperature-programmed reduction, X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. The catalytic properties of the nanostructured Cu-Cr catalysts were evaluated by glycerol hydrogenolysis. The results show that the specific surface area of the obtained Cu-Cr catalyst can reach above 50 m 2 /g, while those of CuO and Cr 2 O 3 are about 10 and 50 m 2 /g, respectively. The surface areas of Cu-Cr catalysts can be controlled by carbon template, Cu/Cr molar ratio, and treatment atmosphere and final temperature. The reduced Cu-Cr catalysts show significant catalytic activity and selectivity in glycerol hydrogenolysis, i.e. above 51% conversion of glycerol and above 96% selectivity to 1,2-propanediol in 4.15 MPa H 2 at 210°C. The Cu-Cr catalysts with low Cu/Cr molar ratio present high conversion of glycerol, which is different from the conventional copper-chromite catalyst.

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Preparation of stable mesoporous inorganic oxides via nano-replication technique

Cited by 61 publications

References 16 publications

Routes of formation and composition of NOx complexes adsorbed on palladium-promoted tungstated zirconia

Routes of formation and composition of NOx complexes adsorbed on palladium-promoted tungstated zirconia

Nanocasting: A Versatile Strategy for Creating Nanostructured Porous Materials

Template Preparation of Highly Active and Selective Cu–Cr Catalysts with High Surface Area for Glycerol Hydrogenolysis

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