Catalytic behavior of ternary Cu/ZnO/Al2O3 systems prepared by homogeneous precipitation in water-gas shift reaction

Atake, Ikuo; Nishida, Kazufumi; Li, Dalin; Shishido, Tetsuya; Oumi, Yasunori; Sano, Tsuneji; Takehira, Katsuomi

doi:10.1016/j.molcata.2007.05.040

Cited by 72 publications

(35 citation statements)

References 35 publications

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“…45) . This finding may be partly due to the higher activity of the AC-derived Cu/ ZnO phase; according to the results previously reported for Cu/ZnO catalysts prepared by homogeneous precipitation using urea, AC is a potential precursor for the preparation of potential CO shift catalyst 45), 46) . In-situ observation of Cu LMM Auger electron spectra of the Cu/ZnO catalyst clearly indicated oxidation of Cu 0 to Cu ＋ during steam treatment, suggesting that the shift reaction proceeds via the reduction-oxidation mechanism expressed by Eqs.…”

Section: E F F E C T S O F P T -D O P I N G O N C U / Z N O / a L2o3supporting

confidence: 63%

Novel Preparation of Uniform Heterogeneous Catalysts Derived from Hydrotalcites

Takehira

2009

J. Jpn. Petrol. Inst.

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Several heterogeneous catalysts were prepared starting from Mg _ Al and Zn _ Al hydrotalcites (HTs) and evaluated for oxidation, ozonation, dehydrogenation and reforming of hydrocarbons, and the CO shift reaction. All catalysts exhibited unique and excellent activities in these reactions. Fe/Mg/Al oxide catalysts prepared from Mg _ Al(Fe) HT exhibited high activity for Baeyer-Villiger oxidation of various ketones and dehydrogenation of ethylbenzene. Ozonation activity of Cu/Mg/Al oxide catalysts similarly prepared from Mg(Cu) _ Al HT was enhanced by the 'memory effect,' as reconstituted HT on the catalyst surface adsorbed oxalic acid and assisted in complete oxidation. Ni/Mg(Al)O catalysts prepared from Mg(Ni) _ Al HT exhibited high and stable activity in steam reforming and oxidative reforming of methane and propane. Moreover, the activity of the Ni catalysts was improved by doping a trace amounts of noble metals by adopting the 'memory effect.' Use of these catalysts in the production of hydrogen for the PEFCs under daily start-up and shut-down operation showed that the catalysts were self-activated and the active Ni metal particles were self-regenerated during the reaction, resulting in high and sustainable activity. CO shift activity of Cu/Zn(Al)O catalysts was also improved by doping a trace Pt or Mg by adopting the memory effect of Zn(Cu) _ Al HT in the precursor, resulting in the high sustainability.

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Section: E F F E C T S O F P T -D O P I N G O N C U / Z N O / a L2o3supporting

confidence: 63%

Novel Preparation of Uniform Heterogeneous Catalysts Derived from Hydrotalcites

Takehira

2009

J. Jpn. Petrol. Inst.

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“…Although ZnO was not reduced under our experimental conditions, partial reduction of surface ZnO which may lead to the formation of a-brass (a dilute alloy of zinc in copper) only a few layers thick on the copper crystallites during the catalyst reduction, cannot be ruled out. In fact, thermodynamic calculations [34] are in favor of such a hypothesis, showing that the equilibrium zinc content in a surface a-brass is about 5% during catalyst reduction at 300 C.…”

Section: Tpr Measurementsmentioning

confidence: 99%

Steam reforming of methanol over x % Cu/Zn–Al 400 500 based catalysts for production of hydrogen: Preparation by adopting memory effect of hydrotalcite and behavior evaluation

Hammoud

Gennequin

Aboukaı̈s

et al. 2015

International Journal of Hydrogen Energy

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“…ions are more acidic than Zn 2? ions and hydrolyze first to form amorphous copper hydroxide [18]. Although the initial precipitation stage is different for Cu(II) and Zn(II), the subsequent evolution of Cu(OH) 2 is strongly affected by the presence of Zn(II), and eventually it is possible to find a greater amount of crystalline CuO than ZnO, as was observed in the CZ-1 sample aged for 1 h (Table 2).…”

Section: Resultsmentioning

confidence: 75%

“…6b). Long aging times increased the CuO microstrain, as observed in Table 2, which was attributed to stronger CuOZnO interactions due to the nanocrystals being more consolidated and compact [16][17][18][19]28]. This structural characteristic could be extended to the reduced catalyst, and stronger Cu/ZnO interactions would be expected.…”

Section: Methanol Steam Reformingmentioning

confidence: 81%

Influence of aging time on the microstructural characteristics of a Cu/ZnO-based catalyst prepared by homogeneous precipitation for use in methanol steam reforming

Sanches

Flores

Silva

2017

Reac Kinet Mech Cat

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Nanocrystalline Cu-ZnO-based catalysts were successfully synthesized via a homogeneous precipitation method. Four aging times were used to prepare the catalysts (1, 3, 12 and 24 h) to study the influence on their textural, structural and catalytic properties. The samples were characterized by N 2 adsorption, powder X-ray diffraction, thermogravimetric analysis, H 2 temperature-programmed desorption and transmission electron microscopy, and the samples were applied to the steam reforming of methanol. The crystallinity and purity of the aurichalcite phase precursor was enhanced after 3 h of aging. Structural changes were observed in the calcined catalysts as the aging time increased. A decreased CuO crystallite size was produced at longer aging times, which enhanced the CuO dispersion and Cu-ZnO interactions. These factors affected the catalytic activity. The catalyst aged for 24 h showed the highest methanol conversion, and a correlation between the structure and activity was verified.

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Catalytic behavior of ternary Cu/ZnO/Al2O3 systems prepared by homogeneous precipitation in water-gas shift reaction

Cited by 72 publications

References 35 publications

Novel Preparation of Uniform Heterogeneous Catalysts Derived from Hydrotalcites

Novel Preparation of Uniform Heterogeneous Catalysts Derived from Hydrotalcites

Steam reforming of methanol over x % Cu/Zn–Al 400 500 based catalysts for production of hydrogen: Preparation by adopting memory effect of hydrotalcite and behavior evaluation

Influence of aging time on the microstructural characteristics of a Cu/ZnO-based catalyst prepared by homogeneous precipitation for use in methanol steam reforming

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