Oxidation Activity and 18O-Isotope Exchange Behavior of Cu-Stabilized Cubic Zirconia

Dongare, Mohan K.; Ramaswamy, V.; Gopinath, Chinnakonda S.; Ramaswamy, A.V.; Scheurell, S.; Brueckner, Martin; Kemnitz, Erhard

doi:10.1006/jcat.2001.3173

Cited by 54 publications

(55 citation statements)

References 16 publications

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“…CuZr samples observed by H 2 -TPR results provide strong evidence that Cu-O-Zr bonds presented in the synthesized samples. Dongare et al [23] observed a decrease of lattice parameters of ZrO 2 with an increase of Cu content (maximum 20 mol%). The authors claimed that incorporation of Cu 2+ in the lattice position of Zr 4+ ions could be the main reason for this.…”

Section: Resultsmentioning

confidence: 97%

“…This observation indicates that the amount of CuO has an influence on the stabilization of ZrO 2 phase. Dongare et al [23] catalysts by sol-gel method and observed that Cu content from 2-20 mol% in CuO-ZrO 2 catalysts stabilized the ZrO 2 in cubic fluorite structure. The observed difference in the final phase of CuO-ZrO 2 catalysts could be due to the adaptation of different preparation methods.…”

Section: Resultsmentioning

confidence: 99%

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Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

et al. 2016

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Mesoporous CuO-ZrO 2 catalysts were prepared and calcined at 500˝C. The performance of the synthesized catalysts for benzylation of benzene using benzyl chloride was studied. The bare support (macroporous ZrO 2 ) offered 45% benzyl chloride conversion after reaction time of 10 h at 75˝C. Significant increase in benzyl chloride conversion (98%) was observed after CuO loading (10 wt. %) on porous ZrO 2 support. The conversion was decreased to 80% with increase of CuO loading to 20 wt. %. Different characterization techniques (XRD, Raman, diffuse reflectance UV-vis, N 2 -physisorption, H 2 -TPR, XPS and acidity measurements) were used to evaluate physico-chemical properties of CuO-ZrO 2 catalysts; the results showed that the surface and structural characteristics of the ZrO 2 phase as well as the interaction between CuO-ZrO 2 species depend strongly on the CuO content. The results also indicated that ZrO 2 support was comprised of monoclinic and tetragonal phases with macropores. An increase of the volume of monoclinic ZrO 2 phase was observed after impregnation of 10 wt. % of CuO; however, stabilization of tetragonal ZrO 2 phase was noticed after loading of 20 wt. % CuO. The presence of low-angle XRD peaks indicates that mesoscopic order is preserved in the calcined CuO-ZrO 2 catalysts. XRD reflections due to CuO phase were not observed in case of 10 wt. % CuO supported ZrO 2 sample; in contrast, the presence of crystalline CuO phase was observed in 20 wt. % CuO supported ZrO 2 sample. The mesoporous 10 wt. % CuO supported ZrO 2 catalyst showed stable catalytic activity for several reaction cycles. The observed high catalytic activity of this catalyst could be attributed to the presence of a higher number of dispersed interactive CuO (Cu 2+ -O-Zr 4+ ) species, easy reducibility, and greater degree of accessible surface Lewis acid sites.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

et al. 2016

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“…The difference in crystallite surface roughness observed for T1 and T2 should play an important role when these materials are used in catalysis. Besides, the substitution of tungsten for zirconium in the lattice generates cationic and anionic vacancies that could be responsible of catalytic reactions; for example, CH 4 and CO oxidation (15).…”

Section: Resultsmentioning

confidence: 99%

“…The possibility of a solid solution between these two oxides has not been contemplated until now, as when zirconia is stabilized with Ca, Cu, Y, La, or Ce (15,16).…”

Section: Introductionmentioning

confidence: 97%

Solid Solutions of WO3into Zirconia in WO3–ZrO2 Catalysts

Cortés-Jácome

Toledo-Antonio

Armendáriz

et al. 2002

Journal of Solid State Chemistry

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“…Y, Ce, Al, Cu) were reported to stabilize tetragonal zirconia. [28][29][30] Because no incorporation of Cu into the ZrO 2 lattice was detectable by XRD or EXAFS (complete reduction of Cu at 673 K, detection limit ~ 1 %), a significant stabilizing effect of Cu centers in ZrO 2 can be excluded for the nanostructured Cu/ZrO 2 catalysts. [3] Garvie et al [31,32] and Chraska et al [33] discussed the influence of the particle size on the stability of the tetragonal phase and found, that for small particles (r critical ≈ 9 nm to 30 nm) the stability of the tetragonal phase at room temperature can be explained by the lower surface energy of t-ZrO 2 compared to m-ZrO 2 .…”

Section: Structure Of the Cuo/zro 2 Precursormentioning

confidence: 99%

In situ investigations of structure–activity relationships of a Cu/ZrO2 catalyst for the steam reforming of methanol

Szizybalski

Girgsdies

Rabis

et al. 2005

Journal of Catalysis

101

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Structure-activity relationships of a nanostructured Cu/ZrO 2 catalyst for the steam reforming of methanol (MSR) were investigated under reaction conditions by in situ X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) combined with on-line mass spectrometry (MS). Temperature programmed activation by reduction in hydrogen or by reduction in a mixture of methanol and water (feed) was studied by time-resolved Cu K edge XANES and TG/DSC/MS measurements. Small and disordered CuO particles were identified as the main copper phase present in the precursors. After extended time on stream and treatment at 673 K in hydrogen, no significant sintering of the copper particles or deactivation of the reduced Cu/ZrO 2 catalysts was detected indicating a superior stability of the material. The initially low steam reforming activity of the Cu/ZrO 2 catalyst after reduction in hydrogen could be significantly increased by a temporary addition of oxygen to the feed. This increased activity after oxidative treatment is correlated to an increasing amount of oxygen in the copper particles.63 Cu NMR studies detected only a minor degree of microstrain in the active copper phase of the Cu/ZrO2 catalyst. The decreased reducibility of CuO/ZrO 2 , the low degree of microstrain, and the correlation between the amount of oxygen remaining in the copper particles and the catalytic activity indicate a different metal support interaction compared to Cu/ZnO catalysts.

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Oxidation Activity and 18O-Isotope Exchange Behavior of Cu-Stabilized Cubic Zirconia

Cited by 54 publications

References 16 publications

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

Solid Solutions of WO3into Zirconia in WO3–ZrO2 Catalysts

In situ investigations of structure–activity relationships of a Cu/ZrO2 catalyst for the steam reforming of methanol

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