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Deng Xiaoyan - One of the best experts on this subject based on the ideXlab platform.
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facile synthesis of magnetic mesoporous silica spheres by a sol gel surface protected etching Incipient Wetness Impregnation approach
Materials Letters, 2020Co-Authors: Sun Liang, Hu Dehao, Zhang Ziyu, Deng XiaoyanAbstract:Abstract We recently synthesized the magnetic mesoporous silica spheres (MMSS) by a sol-gel/surface-protected etching/Incipient Wetness Impregnation approach. Silica spheres (SS) were firstly synthesized by the Stober method, and surface-protected etching allowed convenient conversion of sol-gel derived silica into mesoporous structures (mesoporous silica spheres, MSS). The immobilization of magnetic nanoparticles over MSS supports was addressed by Incipient Wetness Impregnation. XRD, TEM, and nitrogen sorption technique showed successful synthesis as desired. The iron loadings could reach to 32.67 wt% and narrow pore size distribution centered at ca. 4 nm was found. MMSS exhibits superior persulfate (PDS) activation as well as stability for removing the organic compounds. In addition, magnetic separation of the materials offers great prospects for fast and economical reuse.
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Facile synthesis of magnetic mesoporous silica spheres by a sol-gel/surface-protected etching/Incipient Wetness Impregnation approach
Materials Letters, 2020Co-Authors: Sun Liang, Hu Dehao, Zhang Ziyu, Deng XiaoyanAbstract:Abstract We recently synthesized the magnetic mesoporous silica spheres (MMSS) by a sol-gel/surface-protected etching/Incipient Wetness Impregnation approach. Silica spheres (SS) were firstly synthesized by the Stober method, and surface-protected etching allowed convenient conversion of sol-gel derived silica into mesoporous structures (mesoporous silica spheres, MSS). The immobilization of magnetic nanoparticles over MSS supports was addressed by Incipient Wetness Impregnation. XRD, TEM, and nitrogen sorption technique showed successful synthesis as desired. The iron loadings could reach to 32.67 wt% and narrow pore size distribution centered at ca. 4 nm was found. MMSS exhibits superior persulfate (PDS) activation as well as stability for removing the organic compounds. In addition, magnetic separation of the materials offers great prospects for fast and economical reuse.
Susumu Yoshikawa - One of the best experts on this subject based on the ideXlab platform.
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Photocatalytic evolution of hydrogen over mesoporous TiO2 supported NiO photocatalyst prepared by single-step sol–gel process with surfactant template
International Journal of Hydrogen Energy, 2005Co-Authors: Thammanoon Sreethawong, Yoshikazu Suzuki, Susumu YoshikawaAbstract:Abstract Photocatalytic activity of mesoporous titania supported nickel oxide photocatalyst synthesized by single-step sol–gel (SSSG) process combined with surfactant-assisted template method was investigated for hydrogen evolution from an aqueous methanol solution, in comparison with one prepared by conventional Incipient Wetness Impregnation (IWI) method. In single-step sol–gel process, nickel precursor was introduced into the titania sol prepared with the aid of a surfactant template behaving as pore-controlling agent to attain meso-scaled pore. The single-step sol–gel photocatalyst was experimentally found to enhance the photocatalytic evolution of hydrogen rather than the impregnated one. The optimum level of nickel loading in photocatalytic activity test for single-step sol–gel method was slightly higher than that for Incipient Wetness Impregnation method. Characterization results demonstrated the significant modification of physical characteristics of the single-step sol–gel photocatalyst, anticipated to relating to the observation of higher photocatalytic hydrogen evolution activity.
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Photocatalytic evolution of hydrogen over mesoporous TiO2 supported NiO photocatalyst prepared by single-step sol-gel process with surfactant template
International Journal of Hydrogen Energy, 2005Co-Authors: Thammanoon Sreethawong, Yoshikazu Suzuki, Susumu YoshikawaAbstract:Photocatalytic activity of mesoporous titania supported nickel oxide photocatalyst synthesized by single-step sol-gel (SSSG) process combined with surfactant-assisted template method was investigated for hydrogen evolution from an aqueous methanol solution, in comparison with one prepared by conventional Incipient Wetness Impregnation (IWI) method. In single-step sol-gel process, nickel precursor was introduced into the titania sol prepared with the aid of a surfactant template behaving as pore-controlling agent to attain meso-scaled pore. The single-step sol-gel photocatalyst was experimentally found to enhance the photocatalytic evolution of hydrogen rather than the impregnated one. The optimum level of nickel loading in photocatalytic activity test for single-step sol-gel method was slightly higher than that for Incipient Wetness Impregnation method. Characterization results demonstrated the significant modification of physical characteristics of the single-step sol-gel photocatalyst, anticipated to relating to the observation of higher photocatalytic hydrogen evolution activity. © 2004 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
Sun Liang - One of the best experts on this subject based on the ideXlab platform.
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facile synthesis of magnetic mesoporous silica spheres by a sol gel surface protected etching Incipient Wetness Impregnation approach
Materials Letters, 2020Co-Authors: Sun Liang, Hu Dehao, Zhang Ziyu, Deng XiaoyanAbstract:Abstract We recently synthesized the magnetic mesoporous silica spheres (MMSS) by a sol-gel/surface-protected etching/Incipient Wetness Impregnation approach. Silica spheres (SS) were firstly synthesized by the Stober method, and surface-protected etching allowed convenient conversion of sol-gel derived silica into mesoporous structures (mesoporous silica spheres, MSS). The immobilization of magnetic nanoparticles over MSS supports was addressed by Incipient Wetness Impregnation. XRD, TEM, and nitrogen sorption technique showed successful synthesis as desired. The iron loadings could reach to 32.67 wt% and narrow pore size distribution centered at ca. 4 nm was found. MMSS exhibits superior persulfate (PDS) activation as well as stability for removing the organic compounds. In addition, magnetic separation of the materials offers great prospects for fast and economical reuse.
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Facile synthesis of magnetic mesoporous silica spheres by a sol-gel/surface-protected etching/Incipient Wetness Impregnation approach
Materials Letters, 2020Co-Authors: Sun Liang, Hu Dehao, Zhang Ziyu, Deng XiaoyanAbstract:Abstract We recently synthesized the magnetic mesoporous silica spheres (MMSS) by a sol-gel/surface-protected etching/Incipient Wetness Impregnation approach. Silica spheres (SS) were firstly synthesized by the Stober method, and surface-protected etching allowed convenient conversion of sol-gel derived silica into mesoporous structures (mesoporous silica spheres, MSS). The immobilization of magnetic nanoparticles over MSS supports was addressed by Incipient Wetness Impregnation. XRD, TEM, and nitrogen sorption technique showed successful synthesis as desired. The iron loadings could reach to 32.67 wt% and narrow pore size distribution centered at ca. 4 nm was found. MMSS exhibits superior persulfate (PDS) activation as well as stability for removing the organic compounds. In addition, magnetic separation of the materials offers great prospects for fast and economical reuse.
Fegwen Chang - One of the best experts on this subject based on the ideXlab platform.
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preparation of cr2o3 promoted copper catalysts on rice husk ash by Incipient Wetness Impregnation
Applied Catalysis A-general, 2005Co-Authors: Fegwen Chang, Hsienchang YangAbstract:Abstract Rice husk ash (RHA) was utilized as the support material for manufacturing Cr2O3-promoted copper catalyst by Incipient Wetness Impregnation. With constant copper loading at 15 wt%, the effects of Cr content varying from 0 to 5 wt% on surface properties and catalytic activity were investigated. In addition to RHA, commercial silica gel was also used as catalyst support for comparison to study the effect of support material. Surface characterizations were examined extensively by XRD, TPR, SEM, N2 sorption, and H2–N2O titration, while catalytic activities were studied using ethanol dehydrogenation. The results indicate that copper dispersion is enhanced by the initial increase in Cr2O3 promoter content up to 2 wt%, while it then deteriorates gradually upon further increase in promoter content. It has been suggested that an optimal Cr content around 2 wt% not only enhances catalytic activity but also retards catalyst deactivation. Generally speaking, catalyst deactivation results predominantly from copper sintering. Despite the lower BET surface area, RHA is superior to commercial silica gel as a candidate for catalyst support in this work, because the surface of the former may possess more unique pores, while the majority of surface pores on the latter are interconnected and thus can be clogged easily.
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hydrogenation of co2 over nickel catalysts on rice husk ash alumina prepared by Incipient Wetness Impregnation
Applied Catalysis A-general, 2003Co-Authors: Fegwen Chang, Mingtseh Tsay, Mingchung HsiehAbstract:Abstract Nickel catalysts supported on rice husk ash-alumina (Ni/RHA-Al 2 O 3 ) were prepared by the Incipient Wetness Impregnation method. Characterizations were investigated by TPR, XPS, XRD, SEM, and BET techniques. The catalytic activities of nickel catalysts were tested by CO 2 hydrogenation with H 2 /CO 2 ratio of 4:1 for temperatures between 400 and 800 °C. The XPS analysis of Ni/RHA-Al 2 O 3 demonstrated the presence of spinel. The TPR analysis indicated that the interaction between nickel and support was strong and difficult to reduce with more than one nickel oxide compound, such as bulk NiO and two NiAl 2 O 4 -like species. The results of N 2 -adsorption by BET indicated that the maximum surface area was found at 15 wt.% nickel loading with mesopores. The XRD analysis of samples suggested that the crystallite sizes of supported NiO increased with the increase in nickel loading. The CO 2 conversion and CH 4 yield for CO 2 hydrogenation were found to depend on the nickel loading. The reaction temperature of 500 °C might be the optimum temperature for CO 2 hydrogenation to give the maximum yield and selectivity of CH 4 . Furthermore, the hydrogenation tests showed that the performance of Ni/RHA-Al 2 O 3 is better than that of Ni/SiO 2 -Al 2 O 3 .
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dehydrogenation of ethanol over copper catalysts on rice husk ash prepared by Incipient Wetness Impregnation
Applied Catalysis A-general, 2003Co-Authors: Fegwen ChangAbstract:Abstract Copper catalysts supported on rice husk ash (Cu/RHA) prepared by Incipient Wetness Impregnation and the effects of both metal loading and calcination temperature upon the surface structure of the catalyst precursors have been investigated. Surface characterization by XRD, TPR, SEM, and H2–N2O titration, and catalytic activity by ethanol dehydrogenation at temperatures between 473 and 573 K have been examined extensively. The XRD patterns and SEM images show that higher copper loading leads to the agglomeration of CuO crystallites. There is not much apparent transformation in surface morphology to be observed with the variation in calcination temperature. The TPR profiles denote the probable existence of both CuO and Cu2+ in the calcined copper catalysts. CuO exhibits weak metal-support interaction (MSI), while Cu2+ in much lower content exhibits strong MSI. Ethanol conversion and turnover frequency (TOF) show little dependence on copper loading. The activity of catalysts increases with an increase in reaction temperature. Furthermore, copper catalysts supported on rice husk ash display higher catalytic activity than those supported on silica gel, as revealed by the test of ethanol dehydrogenation.
J M Gatica - One of the best experts on this subject based on the ideXlab platform.
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speciation controlled Incipient Wetness Impregnation a rational synthetic approach to prepare sub nanosized and highly active ceria zirconia supported gold catalysts
Journal of Catalysis, 2014Co-Authors: Diana Gaona, Juan C Hernandezgarrido, J J Calvino, Manuel G Basallote, Maria J Fernandeztrujillo, J A Perezomil, J M GaticaAbstract:On the basis of calculated thermodynamic species distribution diagrams and by appropriately controlling the pH of aqueous HAuCl4 solutions, it has been possible to prepare, using a Speciation-controlled Incipient Wetness Impregnation (ScIWI) approach, Au catalysts supported on ceria–zirconia mixed oxides featuring both high gold loadings and excellent metal dispersions. This rational synthesis method is carried out at room temperature. It is both much simpler, in equipment terms, and less expensive than widely used Deposition–Precipitation (DP). Moreover, the use of ScIWI allows overcoming the severe limitations of previously assayed Impregnation methods. With this procedure it is possible to prepare active catalysts in CO oxidation with high efficiency in terms of gold precursor usage, i.e. minimizing Au losses during synthesis. Therefore this, quite amenable, novel strategy for the facile preparation of highly dispersed supported gold catalysts gathers the necessary requirements for both its use at lab scale and an easy scaling-up to industrial levels.
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Speciation-controlled Incipient Wetness Impregnation: A rational synthetic approach to prepare sub-nanosized and highly active ceria–zirconia supported gold catalysts
Journal of Catalysis, 2014Co-Authors: Diana Gaona, J J Calvino, Manuel G Basallote, Juan C. Hernández-garrido, María J. Fernández-trujillo, José A. Pérez-omil, J M GaticaAbstract:On the basis of calculated thermodynamic species distribution diagrams and by appropriately controlling the pH of aqueous HAuCl4 solutions, it has been possible to prepare, using a Speciation-controlled Incipient Wetness Impregnation (ScIWI) approach, Au catalysts supported on ceria–zirconia mixed oxides featuring both high gold loadings and excellent metal dispersions. This rational synthesis method is carried out at room temperature. It is both much simpler, in equipment terms, and less expensive than widely used Deposition–Precipitation (DP). Moreover, the use of ScIWI allows overcoming the severe limitations of previously assayed Impregnation methods. With this procedure it is possible to prepare active catalysts in CO oxidation with high efficiency in terms of gold precursor usage, i.e. minimizing Au losses during synthesis. Therefore this, quite amenable, novel strategy for the facile preparation of highly dispersed supported gold catalysts gathers the necessary requirements for both its use at lab scale and an easy scaling-up to industrial levels.
