Structure and redox properties of bulk and supported manganese oxide catalysts

Arena, Francesco; Torre, Teresa Zardán Gómez de la; Raimondo, Carmelo; Parmaliana, A.

doi:10.1039/b100091h

Cited by 124 publications

(88 citation statements)

References 18 publications

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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: 70%

“…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 Reductionmentioning

confidence: 99%

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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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Section: Temperature Programmed Reductionsupporting

confidence: 70%

Section: Temperature Programmed Reductionmentioning

confidence: 99%

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

2011

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“…Both MnOx/MZIW and MnOx/MZI exhibited similar UV-vis spectra (curves b and c). An absorption band in the 250-315 nm range was observed, which could be reasonably assigned to O 2-f Mn , can be attributed to the unresolved reduction peaks of nonstoichiometrically dispersed MnOx (1.5 < x < 2) phase (reduced in the temperature range between 200 and 325°C) (29,30) and dispersed Mn2O3 (reduced at about 350°C) (29,31,32). For MnOx/MZIW, the lower reduced temperature is about 292°C, indicating the existence of dispersed MnOx.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 4B shows the O2-TPD-MS spectra of the three samples. In the case of MnOx/MZIW, a strong feature peak was observed at 450°C, which was assigned to conversion of nonstoichiometric MnOx species to Mn2O3 (30), and two weaker features also appeared at 520 and 630°C, which belonged to the reduction of Mn2O3 to Mn3O4 and MnO (34). MnOx/MZI exhibited a strong peak at 541°C, which originated from excess bulk oxygen in Mn2O3 (34) and one weak peak at 868°C…”

Section: Resultsmentioning

confidence: 99%

Characterization and Reactivity of MnO_x Supported on Mesoporous Zirconia for Herbicide 2,4-D Mineralization with Ozone

Xing

et al. 2007

Environ. Sci. Technol.

119

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Manganese oxide was supported on mesoporous zirconia (MnO x / MZIW) by wet impregnation, drying, water washing, and calcinations with manganese acetate tetrahydrate as the metal precursor for the first time and was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fouriertransform infrared spectra (FTIR), temperature-programmed reduction (TPR), temperature-programmed oxygen desorption (O 2 -TPD), and UV-vis diffuse reflectance spectra (UV-vis DRS) measurements. The catalyst was found to be highly effective for the mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D) aqueous solution with ozone. The characterization studies showed that nonstoichiometrically MnO x was highly dispersed on mesoporous zirconia by the strong interaction of the [Mn(H 2 O) 6 ] 2+ complex with surface hydroxyls of the support. Moreover, the multivalence oxidation states of MnO x enhanced the electron transfer, causing the higher catalytic reactivity. On the basis of all information obtained under different experimental conditions, MnO x /MZIW enhanced the mineralization of 2,4-D by the formation of • OH radicals resulting from the catalytic decomposition of ozone.

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“…According to the experimental results and literature data, [38,39,[41][42][43] the proposed mechanism in this case is as follows:…”

Section: Crystalline Structure and Morphologymentioning

confidence: 97%

Chemical Vapor Synthesis and Characterization of Manganese Oxides

Chin

Park

et al. 2011

Chemical Vapor Deposition

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Manganese oxide nanoparticles are synthesized by a chemical vapor process using manganese(0) carbonyl as the precursor. The synthesis temperature of the materials is varied from 500 to 1500 8C at 200 8C intervals. These nanomaterials are characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area, and X-ray photoelectron spectroscopy (XPS). XRD shows that the manganese oxide nanoparticles synthesized at 500, 700 -1100, 1300, and 1500 8C are mainly MnO 2 , Mn 2 O 3 , Mn 2 O 3 /Mn 3 O 4 , and Mn 3 O 4 , respectively. The TEM and BET results also confirm that the particle size is on the nanometer scale with a large specific surface area (SSA) of 81 -215 m 2 g À1 . XPS indicates the catalysts to have manganese oxidation states of (2þ), (3þ), or (4þ) depending on the synthesis temperature.

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Structure and redox properties of bulk and supported manganese oxide catalysts

Cited by 124 publications

References 18 publications

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

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

Characterization and Reactivity of MnO_x Supported on Mesoporous Zirconia for Herbicide 2,4-D Mineralization with Ozone

Chemical Vapor Synthesis and Characterization of Manganese Oxides

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Structure and redox properties of bulk and supported manganese oxide catalysts

Cited by 124 publications

References 18 publications

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

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

Characterization and Reactivity of MnOx Supported on Mesoporous Zirconia for Herbicide 2,4-D Mineralization with Ozone

Chemical Vapor Synthesis and Characterization of Manganese Oxides

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Characterization and Reactivity of MnO_x Supported on Mesoporous Zirconia for Herbicide 2,4-D Mineralization with Ozone