Total oxidation catalysts based on manganese or copper oxides and platinum or palladium I: Characterisation

Ferrandon, Magali; Carnö, Johanna; Järås, Sven; Björnbom, Emilia

doi:10.1016/s0926-860x(98)00326-3

Cited by 130 publications

(61 citation statements)

References 18 publications

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“…Compared with the reduction profiles of the MnAl, MM, and CuMnAl samples, the reduction temperature of manganese oxide in CuMnAl sample evidently shifts to lower temperature. A possible explanation for this shift might be that the reduced metal copper catalyzed the reduction of Mn 2 O 3 by hydrogen spillover, and similar results were reported by Ferrandon et al [28] From the results above, we can infer that the reduction of copper oxide species readily promote the reduction of manganese oxide species. In addition, the temperature order of the three reduction peaks is a < b < g, which implies that the reducibility of these surface species is ranked as: copper oxide species (-Cu-O-Cu-) > copper oxide species that connect with manganese oxide species (-Cu-O-Mn-) > the isolated manganese oxide species (-Mn-O-Mn-).…”

Section: Resultssupporting

confidence: 83%

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

120

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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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Section: Resultssupporting

confidence: 83%

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

120

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“…This matches well with the results obtained for the Mn/alumina samples. The characteristic green colour of MnO was observed after the TPR experiments confirming the presence of this oxide, as reported in other works (Ferrandon et al 1999;Stobbe et al 1999;Arena et al 2001;Ramesh et al 2008;Carabineiro et al 2010a). …”

Section: Temperature Programmed Reductionsupporting

confidence: 89%

“…The TPR profile for samples doped with Mn showed two peaks (Table 2). According to what was seen in previous works (Hoflund et al 1995;Ferrandon et al 1999;Stobbe et al 1999;Arena et al 2001;PalDey et al 2005;Xu et al 2006;Ramesh et al 2008;Liang et al 2008;Wang et al 2008Wang et al , 2009Carabineiro et al 2010a), the reduction of MnO 2 to Mn 3 O 4 generates a peak at *350°C, whereas reduction of Mn 3 O 4 to MnO produces a peak at *450°C, sometimes with some overlapping between the two. This matches well with the results obtained for the Mn/alumina samples.…”

Section: Temperature Programmed Reductionsupporting

confidence: 59%

Gold on oxide-doped alumina supports as catalysts for CO oxidation

2011

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The effect of doping a commercial alumina support with metal oxides of Ce, Co, Cu, Fe, La, Mg, Mn, Ni and Zn was investigated. Doped d-Al 2 O 3 samples were obtained by simple physical mixture (PM) of the alumina with the desired commercial oxide and by traditional impregnation of alumina with precursor salts of the same metals followed by calcination (IC). The metal load (7% wt.) was the same in both cases. Gold (1% wt.) was loaded using a liquid phase reductive deposition method. The obtained materials were characterized by adsorption of N 2 at -196°C, temperature programmed reduction, X-ray diffraction, energy-dispersive X-ray spectrometry and transmission electron microscopy. Both samples prepared by PM and IC showed a mixture of the d-alumina phase with the respective metal oxide, but the BET surface areas of the IC samples were, in general, higher than those of the PM materials. The particle size of the oxide phases were larger for the PM samples than for the IC materials. Nevertheless, catalytic experiments for CO oxidation showed that PM samples were much more active than IC. That could be explained by the size of gold nanoparticles, well known to be related with catalytic activity, that was lower in samples prepared by PM (7-16 nm) than by IC (11-17 nm). Gold was found to be in the metallic state. The most active samples were aluminas containing Zn and Fe prepared by PM that had the smallest gold nanoparticles sizes (7-13 and 8-12 nm, respectively) and had room temperature activities for CO conversion of 0.62 and 1.34 mol CO h -1 g Au -1 , respectively, which are larger than those found in the literature for doped c-alumina samples.

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“…TPR of the manganese sample exhibited two peaks at 304 and 460 8C ascribed to the two-step reduction of MnO 2 . [4,38] The H 2 -TPR profile of Co 3 O 4 was also characterised by two reduction peaks located at 345 and 583 8C (Figure 4), which resulted from a progressive reduction of Co 3 O 4 as follows [Eq. (1)]: [39] Co 3 …”

Section: Resultsmentioning

confidence: 99%

Mixed Co–Mn Oxide‐Catalysed Selective Aerobic Oxidation of Vanillyl Alcohol to Vanillin in Base‐Free Conditions

Jha

Patil²,

Rode

2013

ChemPlusChem

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Manganese‐doped cobalt mixed oxide (MnCo‐MO) catalyst was prepared by a solvothermal method. The as‐prepared catalyst was characterised by X‐ray photoelectron spectroscopy, H2 temperature‐programmed reduction, O2 temperature‐programmed oxidation and XRD. This catalyst gave 62 % conversion with 83 % selectivity to vanillin in 2 hours for the liquid‐phase air oxidation of vanillyl alcohol without using base. Three different types of metal oxides were observed in the prepared catalyst, which could be identified as Co3O4, Mn3O4 and CoMn2O4. Among these, the tetragonal phase of CoMn2O4 was found to be more active and selective for vanillyl alcohol oxidation than Co3O4 and Mn3O4. High‐resolution TEM characterisation revealed the morphology of MnCo‐MO nanorods with a particle size of 10 nm. Successful recycling of the catalyst was also established in this oxidation reaction.

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Total oxidation catalysts based on manganese or copper oxides and platinum or palladium I: Characterisation

Cited by 130 publications

References 18 publications

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

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

Gold on oxide-doped alumina supports as catalysts for CO oxidation

Mixed Co–Mn Oxide‐Catalysed Selective Aerobic Oxidation of Vanillyl Alcohol to Vanillin in Base‐Free Conditions

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Total oxidation catalysts based on manganese or copper oxides and platinum or palladium I: Characterisation

Cited by 130 publications

References 18 publications

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

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

Gold on oxide-doped alumina supports as catalysts for CO oxidation

Mixed Co–Mn Oxide‐Catalysed Selective Aerobic Oxidation of Vanillyl Alcohol to Vanillin in Base‐Free Conditions

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Product

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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

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