Co3O4 nanocrystals and Co3O4–MOx binary oxides for CO, CH4 and VOC oxidation at low temperatures: a review

Liotta, Leonarda Francesca; Wu, Hongjing; Pantaleo, G.; Venezia, Anna Maria

doi:10.1039/c3cy00193h

Cited by 331 publications

(207 citation statements)

References 83 publications

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“…42 These different results could be explained by considering that the reduction behaviour of Co 3 O 4 is highly dependent on the preparation method and dispersion of the particles. Large particles are usually reduced to metallic cobalt in a single step, while for nanoparticles a two-step process often occurs.…”

Section: Temperature-programmed Reductionmentioning

confidence: 99%

Co₃O₄ particles grown over nanocrystalline CeO₂: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Pantaleo

Carlo

et al. 2015

Catal. Sci. Technol.

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aCrystalline cobalt oxides were prepared by a precipitation method using three different precipitation agents, ĲNH 4 ) 2 CO 3 , Na 2 CO 3 and COĲNH 2 ) 2 . Cobalt oxide nanoparticles corresponding to a Co 3 O 4 loading of 30 wt% were also deposited over high-surface area nanocrystalline ceria by the same precipitation agents. The effect of calcination temperature, 350 or 650°C, on the morphological and structural properties was evaluated. Characterization by BET, XRD, SEM, TEM, Raman spectroscopy, H 2 -TPR, XPS and NH 3 -TPD was performed and the catalytic properties were explored in the methane oxidation reaction. The nature of the precipitation agent strongly influenced the textural properties of Co 3 O 4 and the Co 3 O 4 -CeO 2 interface. The best control of the particle size was achieved by using COĲNH 2 ) 2 that produced small and regular crystallites of Co 3 O 4 homogeneously deposited over the CeO 2 surface. Such a Co 3 O 4 -CeO 2 system precipitated by urea showed enhanced low-temperature reducibility and high surface Co 3+ concentration, which were identified as the key factors for promoting methane oxidation at low temperature. Moreover, the synergic effect of cobalt oxide and nanocrystalline ceria produced stable full conversion of methane in the entire range of investigated temperature, up to 700-800°C, at which Co 3 O 4 deactivation usually occurs.

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Section: Temperature-programmed Reductionmentioning

confidence: 99%

Co₃O₄ particles grown over nanocrystalline CeO₂: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Pantaleo

Carlo

et al. 2015

Catal. Sci. Technol.

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“…However, due to the high cost of noble metals, many researchers have recently devoted strong efforts to the development of suitable catalysts containing only transition metal oxides [6][7][8][9][10]. In this domain, special attention has been focused on cobalt materials in the spinel form [10], on oxide catalysts [11,12] and on mixed oxides issued from hydrotalcite precursors [13,14]. For the generation of well-dispersed, active and very stable mixed oxides, the Layered Double Hydroxides (LDH) route shows much potential.…”

Section: Introductionmentioning

confidence: 99%

Co-Al Mixed Oxides Prepared via LDH Route Using Microwaves or Ultrasound: Application for Catalytic Toluene Total Oxidation

et al. 2015

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Co6Al2HT hydrotalcite-like compounds were synthesized by three different methods: co-precipitation, microwaves-assisted and ultrasound-assisted methods. The mixed oxides obtained after calcination were studied by several techniques: XRD, TEM, H2-TPR and XPS. They were also tested as catalysts in the reaction of total oxidation of toluene. The physico-chemical studies revealed a modification of the structural characteristics (surface area, morphology) as well as of the reducibility of the formed mixed oxides. The solid prepared by microwaves-assisted synthesis was the most active. Furthermore, a relationship between the ratio of Co 2+ on the surface, the reducibility of the Co-Al mixed oxide and the T50 in toluene oxidation was demonstrated. This suggests a Mars Van Krevelen mechanism for toluene total oxidation on these catalysts.

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“…In general, a redox mechanism occurs in the oxidation of volatile organic compounds in which the surface oxygen or lattice oxygen in the oxide may be involved. In Co and Mn oxides, the lattice oxygen has been found to participate in the oxidation of propene, CO, and VOCs [11][12][13] demonstrating an elevated oxygen mobility in these materials.…”

Section: Introductionmentioning

confidence: 99%

Oxygen Storage Capacity and Oxygen Mobility of Co-Mn-Mg-Al Mixed Oxides and Their Relation in the VOC Oxidation Reaction

2015

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Co-Mn-Mg-Al oxides were synthesized using auto-combustion and co-precipitation techniques. Constant ratios were maintained with (Co + Mn + Mg)/Al equal to 3.0, (Co + Mn)/Mg equal to 1.0 and Co/Mn equal to 0.5. The chemical and structural composition, redox properties, oxygen storage capacity and oxygen mobility were analyzed using X-ray fluorescence (XRF), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), temperature-programmed reduction of hydrogen (H2-TPR), oxygen storage capacity (OSC), oxygen storage complete capacity (OSCC) and isotopic exchange, respectively. The catalytic behavior of the oxides was evaluated in the total oxidation of a mixture of 250 ppm toluene and 250 ppm 2-propanol. The synthesis methodology affected the crystallite size, redox properties, OSC and oxide oxygen mobility, which determined the catalytic behavior. The co-precipitation method got the most active oxide in the oxidation of the volatile organic compound (VOC) mixture because of the improved mobility of oxygen and ability to favor redox processes in the material structure.

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Co3O4 nanocrystals and Co3O4–MOx binary oxides for CO, CH4 and VOC oxidation at low temperatures: a review

Abstract: Co 3 O 4 nanocrystals and Co 3 O 4 -MO x binary oxides for CO, CH 4 and VOC oxidation at low temperatures: a review

Cited by 331 publications

References 83 publications

Co₃O₄ particles grown over nanocrystalline CeO₂: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Co₃O₄ particles grown over nanocrystalline CeO₂: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Co-Al Mixed Oxides Prepared via LDH Route Using Microwaves or Ultrasound: Application for Catalytic Toluene Total Oxidation

Oxygen Storage Capacity and Oxygen Mobility of Co-Mn-Mg-Al Mixed Oxides and Their Relation in the VOC Oxidation Reaction

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Co3O4 nanocrystals and Co3O4–MOx binary oxides for CO, CH4 and VOC oxidation at low temperatures: a review

Abstract: Co 3 O 4 nanocrystals and Co 3 O 4 -MO x binary oxides for CO, CH 4 and VOC oxidation at low temperatures: a review

Cited by 331 publications

References 83 publications

Co3O4 particles grown over nanocrystalline CeO2: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Co3O4 particles grown over nanocrystalline CeO2: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Co-Al Mixed Oxides Prepared via LDH Route Using Microwaves or Ultrasound: Application for Catalytic Toluene Total Oxidation

Oxygen Storage Capacity and Oxygen Mobility of Co-Mn-Mg-Al Mixed Oxides and Their Relation in the VOC Oxidation Reaction

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Co₃O₄ particles grown over nanocrystalline CeO₂: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Co₃O₄ particles grown over nanocrystalline CeO₂: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation