Cluster model study on the surface interactions of γ-alumina-supported metal oxides

Xia, Wensheng; Wan, Haiqin; Chen, Y

doi:10.1016/s1381-1169(98)00145-9

Cited by 28 publications

(13 citation statements)

References 28 publications

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“…Along this line, the density of the remained octahedral vacant sites for 06Mg-Al is about 0.15 mmol/(100 m 2 ), i.e., 0.75 (octahedral vacant sites) − 0.6 (octahedral vacant sites occupied by Mg 2+ ) = 0.15 (remained octahedral vacant sites), which implies that, for per 100 m 2 06Mg-Al support, 0.15 mmol octahedral vacant sites could be used for the incorporation of the dispersed copper ions. Furthermore, with the combination of the previous report that Cu 2+ cations of the dispersed copper oxide species can only incorporate into the octahedral vacant sites of γ -Al 2 O 3 when calcined at 450 • C [4,23], it could be calculated that the dispersion capacity of copper oxide on 06Mg-Al support is about 0.15 mmol/(100 m 2 ), and this prediction has been supported by the results shown in Fig. 2B.…”

Section: Dispersion Of Cuo On Mgo Modified γ -Al 2 O 3 Supportsupporting

confidence: 68%

Influence of magnesia modification on the properties of copper oxide supported on γ-alumina

Wang

Wan

Liu

et al. 2008

Journal of Colloid and Interface Science

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Section: Dispersion Of Cuo On Mgo Modified γ -Al 2 O 3 Supportsupporting

confidence: 68%

Influence of magnesia modification on the properties of copper oxide supported on γ-alumina

Wang

Wan

Liu

et al. 2008

Journal of Colloid and Interface Science

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“…[12a, [20][21][22] For the MnAl sample, a main absorption band at approximately 270 nm and a wide band with a lower intensity at approximately 445 nm were observed. Parida et al observed a similar band at around 270 nm in Mn À MCM-41 sample, and they attributed this band to the charge-transfer transition of O 2À !Mn 3 + in octahedral coordination.…”

Section: Resultsmentioning

confidence: 99%

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

et al. 2011

Chemistry A European J

116

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NO reduction by CO was investigated over CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuOMn2O3/γ-Al2O3 model catalysts before and after CO pretreatment at 300 °C. The CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst exhibited higher catalytic activity than did the other catalysts. Based on X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis diffuse reflectance spectroscopy (DRS), Raman, and H2-temperature-programmed reduction (TPR) results, as well as our previous studies, the possible interaction model between dispersed copper and manganese oxide species as well as γ-Al2O3 surface has been proposed. In this model, Cu and Mn ions occupied the octahedral vacant sites of γ-Al2O3, with the capping oxygen on top of the metal ions to keep the charge conservation. For the fresh CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, the -Cu-O-Cu- and -Mn-O-Mn- species were formed on the surface of γ-Al2O3, respectively; but for the fresh CuO-Mn2O3/γ-Al2O3 catalyst, -Cu-O-Mn- species existed on the surface of -Al2O3. After CO pretreatment, -Cu-□-Cu- and -Mn-□-Mn- (□ represents surface oxygen vacancy (SOV)) species would be formed in CO-pretreated CuO/γ-Al2O3 and CO-pretreated Mn2O3/γ-Al2O3 catalysts, respectively; whereas -Cu-□-Mn- species existed in CO-pretreated CuO-Mn2O3/γ-Al2O3. Herein, a new concept, surface synergetic oxygen vacancy (SSOV), which describes the oxygen vacancy formed between the individual Mn and Cu ions, is proposed for CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst. In addition, the role of SSOV has also been approached by NO temperature-programmed desorption (TPD) and in situ FTIR experiments. The FTIR results of competitive adsorption between NO and CO on all the CO-pretreated CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuO-Mn2O3/γ-Al2O3 samples demonstrated that NO molecules mainly were adsorbed on Mn2+ and CO mainly on Cu+ sites. The current study suggests that the properties of the SSOVs in CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst were significantly different to SOVs formed in CO-pretreated CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, and the SSOVs played an important role in NO reduction by CO.

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“…However, a carbon surface is generally thought to have a weak interaction with the metal particles supported on it, which is evidenced by the tendency of metal particles to sinter on carbon supports [7]. In contrast to carbon, an alumina surface has a strong interaction with metal species and therefore can promote the formation of highly dispersed metal particles [8,9]. Given the different, even completely opposite, surface properties of carbon and alumina, it would be very interesting to create a new material which combines the surface properties of both carbon and alumina.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization, and catalytic application of highly ordered mesoporous alumina-carbon nanocomposites

Wang

et al. 2010

Nano Res.

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Highly ordered mesoporous carbon-alumina nanocomposites (OMCA) have been synthesized for the first time by a multi-component co-assembly method followed by pyrolysis at high temperatures. In this synthesis, resol phenol-formaldehyde resin (PF resin) and alumina sol were respectively used as the carbon and alumina precursors and triblock copolymer Pluronic F127 as the template. N 2 -adsorption measurements, X-ray diffraction, and transmission electron microscopy revealed that, with an increase of the alumina content in the nanocomposite from 11 to 48 wt.%, the pore size increased from 2.9 to 5.0 nm while the ordered mesoporous structure was retained. Further increasing the alumina content to 53 wt.% resulted in wormhole-like structures, although the pore size distribution was still narrow. The nanocomposite walls are composed of continuous carbon and amorphous alumina, which allows the ordered mesostructure to be well preserved even after the removal of alumina by HF etching or the removal of carbon by calcination in air. The OMCA nanocomposites exhibited good thermostability below 1000 °C ; at higher temperatures the ordered mesostructure partially collapsed, associated with a phase transformation from amorphous alumina into γ-Al 2 O 3 . OMCA-supported Pt catalysts exhibited excellent performance in the one-pot transformation of cellulose into hexitols thanks to the unique surface properties of the nanocomposite.

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Cluster model study on the surface interactions of γ-alumina-supported metal oxides

Cited by 28 publications

References 28 publications

Influence of magnesia modification on the properties of copper oxide supported on γ-alumina

Influence of magnesia modification on the properties of copper oxide supported on γ-alumina

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

Synthesis, characterization, and catalytic application of highly ordered mesoporous alumina-carbon nanocomposites

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Cluster model study on the surface interactions of γ-alumina-supported metal oxides

Cited by 28 publications

References 28 publications

Influence of magnesia modification on the properties of copper oxide supported on γ-alumina

Influence of magnesia modification on the properties of copper oxide supported on γ-alumina

The Remarkable Enhancement of CO‐Pretreated CuOMn2O3/γ‐Al2O3 Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

Synthesis, characterization, and catalytic application of highly ordered mesoporous alumina-carbon nanocomposites

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The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy