Spectroscopic characterization of Mn–Co–Ce mixed oxides, active catalysts for COPROX reaction

Gómez, Leticia Ester; Miró, Eduardo Ernesto; Boix, Alicia Viviana

doi:10.1016/j.ijhydene.2013.03.004

Cited by 48 publications

(26 citation statements)

References 46 publications

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“…Lahousse et al established that ␥-MnO 2 catalyst is active for the abatement of VOCs [3]. Some studies have also stressed the importance of the positive role of manganese in Mn/CeO 2 catalysts [26].…”

Section: Introductionmentioning

confidence: 99%

Strong synergism between gold and manganese in an Au–Mn/triple-oxide-support (TOS) oxidation catalyst

Ali

Daous

Khamis

et al. 2015

Applied Catalysis A: General

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Section: Introductionmentioning

confidence: 99%

Strong synergism between gold and manganese in an Au–Mn/triple-oxide-support (TOS) oxidation catalyst

Ali

Daous

Khamis

et al. 2015

Applied Catalysis A: General

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“…The much higher Co 3+ /Co 2+ on the Co‐Mn‐O‐ns (4.08:1) than on the Co‐Mn‐O‐np (1.03:1) can be observed. The Mn 2p 3/2 region in the XPS spectra of the two samples can be fitted into two peaks at around 643.6 and 641.6 corresponding to Mn 4+ and Mn 3+ , respectively . The developed Co‐Mn‐O‐ns catalyst has a higher Mn 4+ /Mn 3+ ratio than that of Co‐Mn‐O‐np.…”

Section: Resultsmentioning

confidence: 94%

“…Laser Raman spectra on the Co‐Mn‐O‐ns and Co‐Mn‐O‐np, along with reference materials (neat Co 3 O 4 ) are presented in Figure . From the feature of Raman spectra, the five strong peaks at 191, 470, 513, 609, and 673 cm −1 assigned to Raman‐active modes depicted as A 1g + E g + 3F 2g of spinel structure of Co 3 O 4 on the Raman spectra of the Co‐Mn‐O‐ns and Co 3 O 4 can be observed; however, only very weak Raman peaks corresponding to Co 3 O 4 spinel structure can be observed on the Raman spectrum of Co‐Mn‐O‐np. This suggests more Co 3 O 4 species, catalytically active for CO PROX reaction, on the Co‐Mn‐O‐ns catalyst as compared to Co‐Mn‐O‐np, which is consistent with the results from XPS analysis shown as above.…”

Section: Resultsmentioning

confidence: 96%

“…The profile of Co‐Mn‐O‐ns or Co‐Mn‐O‐np can be divided into two zones. The peaks between 200 and 350°C can be assigned to the reduction of Co 3+ to Co 2+ and Mn 4+ to Mn 3+ , and the peaks after 350°C can be associated to the reduction of Mn 3+ to Mn 2+ , Co 2+ to metal Co, or Mn 2+ to metal Mn . From our previous reports, the first reduction peaks appearing before 350°C may decisively affect the catalytic performance, and therefore, the first reduction zone is further analyzed.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, in the O 1s XPS peak region of both Co‐Mn‐O‐ns and Co‐Mn‐O‐np shown in Figures c, f, respectively, asymmetric two band structures can be observed. From references, the fitted O 1s XPS peaks at around 529.9 and 531.6 eV of Co‐Mn‐O‐ns (529.9 and 531.8 eV for Co‐Mn‐O‐np) are assigned to the characteristic peaks corresponding to lattice O and adsorbed O, respectively. Correlated to reaction results, more surface lattice O is favorable for promoting the CO PROX catalytic activity of the Co‐Mn‐O‐ns catalyst.…”

Section: Resultsmentioning

confidence: 99%

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Novel Co‐Mn‐O nanosheet catalyst for CO preferential oxidation toward hydrogen purification

et al. 2014

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Co-Mn-O composite oxide nanosheet catalyst was successfully prepared using a facile urea-assisted one-step hydrothermal method in the absence of organic or organic templating reagent. Co-Mn-O nanosheet catalyst was optimized by varying hydrothermal process parameters such as molar ratio of Co-Mn to urea, hydrothermal temperature, and hydrothermal time. Various characterization techniques including scanning electron microscopy, X-ray diffraction, nitrogen adsorption, X-ray photoelectron spectroscopy, Raman spectroscopy, and H 2 temperature-programmed reduction were used to reveal the relationship between catalyst nature and catalytic performance in CO preferential oxidation (CO PROX) in excess H 2 . The developed Co-Mn-O nanosheet catalyst have demonstrated much superior catalytic performance to Co-Mn-O nanoparticle, particularly in the low temperature range, and 100% CO conversion over the developed Co-Mn-O nanosheet can be achieved in temperature range of 50 to 150 C at 10,000 mL g 21 h 21 of gas hourly space velocity in the standard feed. Furthermore, the almost complete CO removal over Co-Mn-O nanosheet at 125 C of low temperature with 94.9% selectivity can be achieved even in the simulated reformed gas. The excellent catalytic performance is ascribed to nanosheet morphology, more surface Co 31 , smaller average crystallite size, higher reducibility, and strong Co-Mn interaction. Catalytic stability investigation indicates the developed nanostructured catalyst exhibits high catalytic stability for CO PROX reaction in simulated gas. The developed Co-Mn-O nanosheet catalyst can be a potential candidate for catalytic elimination of trace CO from H 2 -rich gas for Proton exchange membrane fuel cell applications. Reaction conditions: 100 mg catalyst, GHSV 5 15,000 mL h 21 g 21 , 1.0 vol % CO, 1.0 vol % O 2 , 50 vol % H 2 , Ar balance. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] 242 Figure 8. The CO conversion (a) and O 2 selectivity to CO 2 (b) over the Co-Mn-O-ns samples prepared with diverse n Co-Mn/Urea . Reaction conditions: GHSV 5 15,000 mL h 21 g 21 , 1.0 vol % CO, 1.0 vol % O 2 , 50 vol % H 2 , Ar balance. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

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Oxidation of Carbon Monoxide on Co−Ce‐Modified ZSM‐5 Zeolites: Impact of Mixed Oxo‐Species

et al. 2020

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The main idea of the present work is the creation of new types of redox active sites by using zeolite as a matrix. Structure and catalytic activity in CO oxidation were studied for catalysts based on CoÀ Ce-modified ZSM-5 synthesized by sequential incipient wetness impregnation. Synergy of action of the two additives is observed. The most active is the catalyst with the ratio Co : Ce = 3 : 1. According to TEM, XPS, UV-vis-DRS, DRIFTS and in situ CO-reduction studies, the interaction of metals occurs in the channels of the zeolite with the formation of previously unknown joint structures in which Co III and Ce III are stabilized. Apparently, these structures are represented by mixed CoÀ Ce oxo-cations [Co x CeO y ] n + . A new absorption band at 2179 cm À 1 appearing in the DRIFT spectra of adsorbed CO is associated with mixed species. The catalytic activity in the oxidation of CO correlates with amount of these structures.[a] M.

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Spectroscopic characterization of Mn–Co–Ce mixed oxides, active catalysts for COPROX reaction

Cited by 48 publications

References 46 publications

Strong synergism between gold and manganese in an Au–Mn/triple-oxide-support (TOS) oxidation catalyst

Strong synergism between gold and manganese in an Au–Mn/triple-oxide-support (TOS) oxidation catalyst

Novel Co‐Mn‐O nanosheet catalyst for CO preferential oxidation toward hydrogen purification

Oxidation of Carbon Monoxide on Co−Ce‐Modified ZSM‐5 Zeolites: Impact of Mixed Oxo‐Species

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