Synthesis of Supported Catalysts by Impregnation and Drying Using Aqueous Chelated Metal Complexes

Dillen, A.J. van; Terorde, Robert J. A. M.; Lensveld, Dennis J.; Geus, J.W.; Jong, Krijn P. de

doi:10.1002/chin.200336195

Cited by 15 publications

(16 citation statements)

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“…Nevertheless, the fundamental phenomena involved upon impregnation, drying and even calcination are rather complex and difficult to be rationalised in a simple model. A limited interaction between the metal precursor and the support body can conduct to the redistribution of the active phase during the drying and calcination steps, causing the migration of the active phase toward the external edge of the support body to produce egg-shell catalyst [13,31,45]. Therefore, the optimization of the interaction between the metal precursor and the support is crucial to tune the distribution of the active component within the support body and hence the catalyst performance.…”

Section: Introductionmentioning

confidence: 99%

Citric acid-assisted synthesis of γ-alumina-supported high loading CoMo sulfide catalysts for the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) reactions

et al. 2015

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In the present work, the effect of the citric acid (i.e., adsorption-assisting agent) and the thermal treatment over the citric acid-synthesized CoMo catalyst precursors were investigated. The catalysts were prepared by wet coimpregnation of c-alumina extrude with citric acid-containing CoMo aqueous solution in acid medium (pH = 2-3) and treated at various temperatures (typically between 110 and 400°C) in an air atmosphere. The calumina-supported CoMo sulfide catalysts were evaluated using two different feeds (a model feedstock containing various S and N compounds (hereafter feed 1) and a real feedstock (hereafter feed 2). It was found that the synthesis of alumina-supported high loading CoMo catalyst precursor by wet co-impregnation using citric acid as chelating agent in the CoMo impregnation solution takes place mainly through the uniform deposition-precipitation of Co aqueous complex and Mo citrate onto alumina. This process leads to the formation of nanodispersed Co and Mo species that effectively mitigate the formation of b-CoMoO 4 during the thermal treatment at high temperature (i.e., 350°C). The decomposition reaction of Co aqueouscomplex and Mo citrate deposited on alumina started at 220°C. The gradual degradation of the whole metal citrate with increasing treatment temperature decreased the catalyst activity because of the apparent formation of poorly reducible mixed-metal oxides in the catalyst precursor. The use of citric acid to synthesize the CoMo formulations enhances not only the C-S bond scission through the direct desulfurization pathway, but also the hydrogenation route.

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Section: Introductionmentioning

confidence: 99%

Citric acid-assisted synthesis of γ-alumina-supported high loading CoMo sulfide catalysts for the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) reactions

et al. 2015

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“…The ammonium iron citrate used in the preparation of the supported samples contained low amounts of sulphur and sodium and efficiently introduced these promoters in the catalysts (Table S3). The use of ammonium iron citrate as the metal precursor provides a homogeneous distribution of the iron nanoparticles on the support, in contrast to extensive clustering that is observed when using iron nitrate (26). Fe nanoparticle aggregation could lead to low catalytic activity and high methane selectivity as observed when using bulk iron catalysts.…”

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confidence: 99%

Supported Iron Nanoparticles as Catalysts for Sustainable Production of Lower Olefins

Galvis

Bitter

Khare

et al. 2012

Science

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660

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Lower olefins are key building blocks for the manufacture of plastics, cosmetics, and drugs. Traditionally, olefins with two to four carbons are produced by steam cracking of crude oil-derived naphtha, but there is a pressing need for alternative feedstocks and processes in view of supply limitations and of environmental issues. Although the Fischer-Tropsch synthesis has long offered a means to convert coal, biomass, and natural gas into hydrocarbon derivatives through the intermediacy of synthesis gas (a mixture of molecular hydrogen and carbon monoxide), selectivity toward lower olefins tends to be low. We report on the conversion of synthesis gas to C(2) through C(4) olefins with selectivity up to 60 weight percent, using catalysts that constitute iron nanoparticles (promoted by sulfur plus sodium) homogeneously dispersed on weakly interactive α-alumina or carbon nanofiber supports.

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“…We expect this to lead to the formation of another acetylacetonate bridge between two Ho(III) ions. The gradual removal of solvent is imperative in this particle preparation method, allowing acetylacetonate to exert a bridging effect between Ho(III) ions ( 17 ).…”

Section: Resultsmentioning

confidence: 99%

Holmium Nanoparticles: Preparation and In Vitro Characterization of a New Device for Radioablation of Solid Malignancies

et al. 2010

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PurposeThe present study introduces the preparation and in vitro characterization of a nanoparticle device comprising holmium acetylacetonate for radioablation of unresectable solid malignancies.MethodsHoAcAc nanoparticles were prepared by dissolving holmium acetylacetonate in chloroform, followed by emulsification in an aqueous solution of a surfactant and evaporation of the solvent. The diameter, surface morphology, holmium content, and zeta potential were measured, and thermal behavior of the resulting particles was investigated. The stability of the particles was tested in HEPES buffer. The r2* relaxivity of protons and mass attenuation coefficient of the nanoparticles were determined. The particle diameter and surface morphology were studied after neutron activation.ResultsSpherical particles with a smooth surface and diameter of 78 ± 10 nm were obtained, and the particles were stable in buffer. Neutron irradiation did not damage the particles, and adequate amounts of activity were produced for nuclear imaging and radioablation of malignancies through intratumoral injections.ConclusionsThe present study demonstrates that HoAcAc nanoparticles were prepared using a solvent evaporation process. The particle diameter can easily be adapted and can be optimized for specific therapeutic applications and tumor types.

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Synthesis of Supported Catalysts by Impregnation and Drying Using Aqueous Chelated Metal Complexes

Cited by 15 publications

References 1 publication

Citric acid-assisted synthesis of γ-alumina-supported high loading CoMo sulfide catalysts for the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) reactions

Citric acid-assisted synthesis of γ-alumina-supported high loading CoMo sulfide catalysts for the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) reactions

Supported Iron Nanoparticles as Catalysts for Sustainable Production of Lower Olefins

Holmium Nanoparticles: Preparation and In Vitro Characterization of a New Device for Radioablation of Solid Malignancies

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