Preparation of silica-supported copper catalysts by means of deposition-precipitation

Grift, C.J.G. van der; Elberse, P. A.; Mulder, Anne-Claire; Geus, J.W.

doi:10.1016/s0166-9834(00)82204-6

Cited by 154 publications

(64 citation statements)

References 12 publications

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“…Incomplete reductions of Cu-ZnO/Al 2 O 3 at 503 K [16,17] and of Cu/SiO 2 at 500 K [28,36,37] have been reported and the reduction of CuO x phases may lead to an increase in reaction rates with time on stream. van der Grift et al [36,37] found by temperature programmed reduction (TPR) that several copper hydrosilicate phases reduced only above 600 K. Brands et al [28] found that Cu metal surface area increased, when a Cu/SiO 2 catalyst previously reduced at 600 K was re-reduced at 700 K. Clausen et al [26] reported that the morphology of Cu particles formed on SiO 2 by reduction in various synthesis gas mixtures at 493 K was insensitive to gas composition. Although Cu particle sizes were not reported, inspection of the EXAFS data presented with the paper indicates that the Cu particles on SiO 2 were similar in size to the particles on ZnO, for which dynamical behavior was clearly observed.…”

Section: Discussionmentioning

confidence: 99%

New insights into methanol synthesis catalysts from X-ray absorption spectroscopy

Meitzner¹,

Iglesia

1999

Catalysis Today

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X-ray absorption spectroscopic studies from several different groups provide a consistent structural picture of methanol synthesis catalysts. Copper metal is the principal Cu species detected in all in-situ XAS studies. A small amount of Cu(II) persisted in many samples reduced below 600 K, but it appears to be catalytically irrelevant. Cu(I) was not detected in any of the in-situ XAS studies. The Zn structure did not change in response to chemical treatments in any of the ZnO-containing methanol synthesis catalysts.We conclude that the slow approach to steady-state rate of methanol synthesis from CO/H 2 mixtures cannot result from changes in the Cu metal component of Cu/SiO 2 catalysts. By eliminating this possibility, we provide indirect evidence for the proposal that initial induction periods reflect slow changes in the surface of the SiO 2 or ZnO component in the catalysts. A bifunctional mechanism involving the formation of formate from CO on support hydroxyl groups would increase methanol synthesis rates as OH groups are formed by hydrolysis of Si-O bonds using the H 2 O formed in slow methanation side reactions. The bifunctional mechanism is not required for the synthesis of methanol from CO 2 -containing mixtures, because formate can form on Cu directly from CO 2 and H 2 .

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Section: Discussionmentioning

confidence: 99%

New insights into methanol synthesis catalysts from X-ray absorption spectroscopy

Meitzner¹,

Iglesia

1999

Catalysis Today

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“…Promoted and unpromoted silica supported copper catalysts were prepared by homogeneous deposition precipitation of copper nitrate trihydrate (Merck, > 99.5% pure) and zinc nitrate hexahydrate (Janssen, > 98% pure) onto Aerosil 200 silica (Degussa), according to the method described by Van der Grift et al [17]. The precipitate was washed twice with doubly distilled water and dried at 363 K overnight.…”

Section: Methodsmentioning

confidence: 99%

The effect of the reduction temperature on the structure of Cu/ZnO/SiO2 catalysts for methanol synthesis

Batyrev

Heuvel

Beckers

et al. 2005

Journal of Catalysis

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The effect of the reduction temperature on the structure of Cu/ZnO/SiO2 catalysts for methanol synthesis Batyrev, E.; van den Heuvel, J.C.; Beckers, J.; Jansen, W.P.A.; Castricum, H.L. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Abstract: The structure of Cu/SiO 2 and Cu/ZnO/SiO 2 catalysts was studied after reduction at 450-1300 K. The influence of the ZnO promoter on the exposed Cu surface area and metal cluster size was determined by N 2 O chemisorption and X-ray diffraction. After reduction at 450 K, the metal surface area amounted to 9 m 2 /g cat for both catalysts. Oxygen uptake during N 2 O chemisorption increased significantly up to reduction temperatures of 800-900 K. This increase was most prominent for the ZnO-promoted catalyst, although no oxygen uptake was observed for a similarly treated ZnO/SiO 2 sample. The behaviour of the promoted catalyst can be explained by formation of Zn 0 , surface alloying, and segregation of ZnO x species on top of Cu clusters. The high thermostability of the catalysts was confirmed by in-situ XRD measurements. The Cu crystallite size in both catalysts was about 4 nm, and did not increase when the reduction temperature was raised to 1100 K for 1 hour.

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“…This method has previously been reported by our laboratory, 16 which is opposite to the previous deposition-precipitation (DP) process. 17,18 It is well-known that the stability of active phase in supported catalysts not only depends on support, the preparation method, but also relates with the thermal treatment such as calcination and reduction. Accordingly, this work was undertaken with the aim of exploring the capability of the PG method for the preparation of Co/SiO 2 catalyst and to see whether such a method can yield cobalt species dispersed and stabilized by the carrier.…”

Section: Introductionmentioning

confidence: 99%

Liquid Phase Hydrogenolysis of Biomass‐derived Lactate to 1,2‐Propanediol over Silica Supported Cobalt Nanocatalyst

et al. 2011

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Liquid phase hydrogenolysis of ethyl lactate to 1,2-propanediol was performed over silica supporting cobalt catalysts prepared by two different methods: precipitation-gel (PG) technique and deposition-precipitation (DP) procedure. The cobalt species (Co 3 O 4 /cobalt phyllosilicate) present in the corresponding calcined PG and DP catalysts were different as a consequence of the preparation methods, and Co-OH-Co olation and Si-O-Co oxolation molecular mechanisms were employed to elucidate the chemical phenomena during the different preparation procedures. In addition, the texture (BET), reduction behavior (TPR and in-situ XRD), surface dispersion and state of cobalt species (XPS), and catalytic performance differ greatly between the samples. Because of small particle size, high dispersion of cobalt species and facile reducibility, the Co/SiO 2 catalyst prepared by precipitation-gel method presented a much higher activity than the catalyst prepared by deposition-precipitation method. Metallic cobalt is assumed to be the catalytically active site for the hydrogenolysis reaction according to the catalytic results of both cobalt samples reduced at different temperatures and the structure changes after reaction.

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Preparation of silica-supported copper catalysts by means of deposition-precipitation

Cited by 154 publications

References 12 publications

New insights into methanol synthesis catalysts from X-ray absorption spectroscopy

New insights into methanol synthesis catalysts from X-ray absorption spectroscopy

The effect of the reduction temperature on the structure of Cu/ZnO/SiO2 catalysts for methanol synthesis

Liquid Phase Hydrogenolysis of Biomass‐derived Lactate to 1,2‐Propanediol over Silica Supported Cobalt Nanocatalyst

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