Structure of Co and Co oxide clusters in MCM-41

Jentys, Andreas; Pham, Ngan Hoang; Vinek, H.; Englisch, Martin; Lercher, Johannes A.

doi:10.1016/s0920-5861(97)00119-3

Cited by 28 publications

(18 citation statements)

References 21 publications

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“…For example, the incorporation of Co metal or Co oxides into the molecular sieves of MCM-41 was reported to increase the catalyst performance in relation to catalyst sintering during reforming reactions. 30,31 In addition, the size of metal clusters has been reported to be strongly influenced by the pore size of the MCM-41 support, the larger pores of MCM-41 resulting in larger metal particles. 31−33 The study of Ni/MCM-41 catalysts during biomass gasification has shown that the size of NiO particles was increased and the NiO particles were found to move from inside of the pores of the MCM-41 to outside the pores when the Ni loading was increased from 5 to more than 20 wt %.…”

Section: ■ Introductionmentioning

confidence: 99%

Effect of Ni Particle Location within the Mesoporous MCM-41 Support for Hydrogen Production from the Catalytic Gasification of Biomass

Dong

Onwudili

et al. 2013

ACS Sustainable Chem. Eng.

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Thermal processing of biomass in the presence of a catalyst is a promising technology to generate H 2 -rich gases for fuelling the future. Metal particles loaded on porous supports have been widely used for biomass gasification. However, no detailed research has been designed for describing the catalytic performance of nickel particles located inside compared to outside the pores of the supports. In this work, two groups of Ni/MCM-41 catalysts were prepared: Iseries catalysts where most of the NiO particles were located inside the mesopores of MCM-41 and O-series catalysts where most of the NiO particles were located outside the pores of MCM-41. The prepared catalysts were used in the pyrolysiscatalytic gasification of wood sawdust using a two-stage fixedbed reaction system. Gasification on the I-series catalysts generated more gas and hydrogen and lower oil, compared with the Oseries catalysts. Hydrogen production was increased from 16.46 to 21.26 (mmol H 2 g −1 wood) when the catalyst was changed from 20%Ni−O to 20%Ni−I. The better performance of the I-series catalysts in relation to hydrogen production is suggested to be due to the longer residence time of pyrolysis reactants inside the pores of the MCM-41 and thus a longer contact time between reactants and active Ni sites. In addition, the high dispersion of the fine NiO particles inside the pores of the MCM-41 support enhances the catalytic performance of the I-series catalyst during the pyrolysis/gasification of biomass.

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Section: ■ Introductionmentioning

confidence: 99%

Effect of Ni Particle Location within the Mesoporous MCM-41 Support for Hydrogen Production from the Catalytic Gasification of Biomass

Dong

Onwudili

et al. 2013

ACS Sustainable Chem. Eng.

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“…There is a strong X-ray diffraction evidence of monolayer or sub-monolayer dispersion of cobaltous salts on the w x surface of alumina carrier 11 . Clusters of five to six cobalt atoms were reported in the mezopores of w x CorMCM-41 by Jentys et al 12 .…”

Section: žmentioning

confidence: 89%

Dynamics of water vapor adsorption on humidity-indicating silica gel

Balköse

Ulutan

Özkan

et al. 1998

Applied Surface Science

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Well-defined CoCl -containing silica gels were prepared by impregnation of the aqueous solution of the salt to silica 2 hydrogel, drying and aging methods. Silica gels having 392-437 m 2 g y1 surface area and 0.21-0.37 cm 3 g y1 pore volume and having an average particle size of 3 mm were obtained. Aging in CoCl solutions decreased the surface area of silica 2 gels from 540 cm 2 g y1 to 392-430 m 2 g y1 and pore volume from 0.27 to 0.21-0.23 cm 3 g y1 for CoCl concentration 2 smaller than 0.28 mol dm y3 in silica gel. Adsorbed water desorbed from the gels absorbing 1917-2555 J g y1 energy as determined by differential scanning calorimetry. The CoCl -containing gels were successfully used in dynamic column 2 experiments, with linear relation between velocities of inlet air and movement of blue to pink boundary. The colour change also makes the detection of the defects in column filling which causes air channelling. q 1998 Elsevier Science B.V. All rights reserved.

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“…Aqueous impregnation is one of the most widely-used procedures involved in the preparation of supported heterogeneous catalysts [10]. For example, A. Jentys and co-workers [11] have shown that impregnation of MCM-41 materials with aqueous solutions of cobalt nitrate results in small cobalt clusters being incorporated inside the amorphous mesostructure. Most of these publications have mainly addressed the structure of the oxide and metal particles incorporated into the porous structure.…”

Section: Introductionmentioning

confidence: 99%