Characterization studies of calcined, promoted and non‐promoted methanol‐steam reforming catalysts

Idem, Raphael; Bakhshi, Narendra N.

doi:10.1002/cjce.5450740214

Cited by 24 publications

(14 citation statements)

References 28 publications

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“…Regarding the active state of Cu/ZnO catalysts, different authors claim that the ratio of Cu/Cu + governs the methanol conversion (24). This interpretation is closely related to the model of the active Cu/ZnO phase in methanol synthesis developed by Klier (25).…”

Section: Introductionmentioning

confidence: 64%

Redox Behavior of Copper Oxide/Zinc Oxide Catalysts in the Steam Reforming of Methanol Studied by in Situ X-Ray Diffraction and Absorption Spectroscopy

Günter

Ressler

Jentoft

et al. 2001

Journal of Catalysis

249

162

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The bulk structure of copper in various binary Cu/ZnO catalysts for steam reforming of methanol under activation and working conditions is studied by in situ X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). The evolution of bulk phases from CuO/ZnO precursors during activation with hydrogen was studied using temperature programmed reduction (TPR) (448 -523 K, 2 vol-% H 2 with and without water vapor). With decreasing copper content the onset of reduction is shifted from 473 K (pure CuO) to 443 K (40 mol-% Cu) accompanied by a decrease in Cu crystallite sizes (from 210 Å to 40 Å). Using time -resolved in situ XANES measurements at the Cu K edge during TPR experiments the degree of reduction was monitored. It is shown that Cu(I) oxide forms prior to Cu. Adding oxygen to the feed gas leads to the formation of a mixture of Cu(II) and Cu(I) oxide accompanied by a complete loss of activity. After switching back to steam reforming conditions a higher activity is attained while the catalyst shows an increased Cu crystallite size (up to 40%). EXAFS measurements at the Cu K and the Zn K edge indicate a structural disorder of the Cu particles in the medium range order based on increasing Debye-Waller factors for higher Cu-Cu shells . Furthermore, the dissolution of Zn atoms (up to ~ 4 mol-%) in the copper lattice is detected. Upon oxidation/reduction cycles activity is increased, the disorder in the copper particles increases, and Zn segregates out of the copper bulk. A structural model is proposed which ascribes the enhanced activity to structurally disordered (strained) copper particles due to an improved interface interaction with ZnO.

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Section: Introductionmentioning

confidence: 64%

Redox Behavior of Copper Oxide/Zinc Oxide Catalysts in the Steam Reforming of Methanol Studied by in Situ X-Ray Diffraction and Absorption Spectroscopy

Günter

Ressler

Jentoft

et al. 2001

Journal of Catalysis

249

162

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“…Zinc oxide is well known to promote the copper [22] in functionality, possibly by the so called spill-over effect [23]. The promoter effect of manganese and chromium oxide is mainly attributed to stabilisation of the Cu(I) species also by formation of a spinell [24]. Cu(I) is considered to be the real active species by several researchers (e.g.…”

Section: Introductionmentioning

confidence: 99%

Preparation of copper catalyst washcoats for methanol steam reforming in microchannels based on nanoparticles

Pfeifer¹,

Schubert²,

Emig³

2005

Applied Catalysis A: General

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“…As the promoter manganese concentration in the catalyst was increased, the peaks of CuAl 2 O 4 and CuMnO 2 showed an increase in intensity, while the peak intensity of CuO dropped. Cu 2 O, CuO and CuAl 2 O 4 were also identified for copper catalysts by Idem and Bakhshi [14], and Robinson and Mol [15] using TPR and XRD characterization techniques.…”

Section: Catalyst Characterizationmentioning

confidence: 93%

Low-temperature water-gas shift reaction over Mn-promoted Cu/Al2O3 catalysts

2006

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Water-gas-shift reaction was carried our over a series of Mn-promoted Cu/Al 2 O 3 catalysts in the temperature range of 448-533 K. The catalysts were characterized suitably by various techniques. The catalyst containing 8.55 wt% Mn was found to be the most active one among five catalysts tested. A maximum CO conversion of 90% was obtained over this catalyst at 513 K with a CO space-time of 5.33 h. The catalysts were found to be structure sensitive for the low-temperature water-gas shift reaction. A detailed kinetic study was performed for the reaction under investigation over the best catalyst. The kinetic data were fitted to two different models and the redox model was found to the better one than the other. From the estimated kinetic constant, the activation energy was determined to be 81 kJ/mol for the water-gas shift reaction in the temperature range of 448-463 K.

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Characterization studies of calcined, promoted and non‐promoted methanol‐steam reforming catalysts

Cited by 24 publications

References 28 publications

Redox Behavior of Copper Oxide/Zinc Oxide Catalysts in the Steam Reforming of Methanol Studied by in Situ X-Ray Diffraction and Absorption Spectroscopy

Redox Behavior of Copper Oxide/Zinc Oxide Catalysts in the Steam Reforming of Methanol Studied by in Situ X-Ray Diffraction and Absorption Spectroscopy

Preparation of copper catalyst washcoats for methanol steam reforming in microchannels based on nanoparticles

Low-temperature water-gas shift reaction over Mn-promoted Cu/Al2O3 catalysts

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