Bond Energy Effects in Methane Oxidative Coupling on Pyrochlore Structures

Petit, C.; Kaddouri, A.; Libs, S.; Kiennemann, A.; Rehspringer, Jean‐Luc; Poix, P.

doi:10.1006/jcat.1993.1087

Cited by 25 publications

(9 citation statements)

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“…It can be seen from Figure 3 that the ν 1 (B–O) of all doping samples slightly shift to a higher frequency compared to LS, indicating changes in B–O bond strength. It was reported that B–O bonding energy is always lower than A–O′ in pyrochlore crystallite and that the difference in the B–O bond strength would affect the release of lattice oxygens and oxygen vacancy formation [24]. Therefore, the generation of surface oxygen defects, by breaking oxygen bonds in the vicinity of the surface, may be promoted by the incorporation of Ca/Co ions.…”

Section: Resultsmentioning

confidence: 99%

Catalytic Oxidation of Soot on a Novel Active Ca-Co Dually-Doped Lanthanum Tin Pyrochlore Oxide

Wang

Cui

et al. 2018

Materials

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A novel active Ca-Co dually-doping pyrochlore oxide La2−xCaxSn2−yCoyO7 catalyst was synthesized by the sol-gel method for catalytic oxidation of soot particulates. The microstructure, atomic valence, reduction, and adsorption performance were investigated by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), H2-TPR (temperature-programmed reduction), and in situ diffuse reflection infrared Fourier transformed (DRIFTS) techniques. Temperature programmed oxidation (TPO) tests were performed with the mixture of soot-catalyst under tight contact conditions to evaluate the catalytic activity for soot combustion. Synergetic effect between Ca and Co improved the structure and redox properties of the solids, increased the surface oxygen vacancies, and provided a suitable electropositivity for oxide, directly resulting in the decreased ignition temperature for catalyzed soot oxidation as low as 317 °C. The presence of NO in O2 further promoted soot oxidation over the catalysts with the ignition temperature decreased to about 300 °C. The DRIFTS results reveal that decomposition of less stable surface nitrites may account for NO2 formation in the ignition period of soot combustion, which thus participate in the auxiliary combustion process.

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Section: Resultsmentioning

confidence: 99%

Catalytic Oxidation of Soot on a Novel Active Ca-Co Dually-Doped Lanthanum Tin Pyrochlore Oxide

Wang

Cui

et al. 2018

Materials

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“…breaking oxygen lattice bonds [22]. It has been also reported, based on theoretical and calculations of bond energy, that the difference in SnAO bond strength affects oxygen vacancy formation [32]. Therefore, the generation of surface oxygen defects, by breaking oxygen bonds in vicinity of surface, is promoted with the increasing r, which facilitates oxygen migration in oxidation reactions.…”

Section: Ftir Characterizationmentioning

confidence: 96%

Catalytic combustion of soot particulates over rare-earth substituted Ln2Sn2O7 pyrochlores (Ln = La, Nd and Sm)

Wang

Zhu

et al. 2016

Journal of Colloid and Interface Science

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“…The higher methane oxidation activity of the perovskite having higher iron content is thought to be attributable to oxygen vacancies present in the perovskite crystal lattice; these vacancies serve as active sites for methane adsorption and dissociation. [11] It is believed that the oxygen vacancy concentration is increased with increasing iron content in the perovskite lattice since Fe 3+ substitution for Ti 4+ produces oxygen vacancies for charge compensation. On the other hand, the Y 0.08 Sr 0.92 Ti 0.80 Fe 0.20 O 3-δ sample synthesized by the Pechini method exhibited the best catalytic activity for methane oxidation.…”

Section: Resultsmentioning

confidence: 99%

Catalytic activity of Y and Fe co-doped SrTio3 perovskites for methane oxidation

Yoon

Kim

Lee

et al. 2011

Electron. Mater. Lett.

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Y and Fe co-doped SrTiO3 powder with a phase-pure perovskite structure were synthesized by solid state reaction (SSR) and the Pechini method. The catalytic activity of Y0.08Sr0.92FexTi1-xO3-δ (x = 0.1, 0.2, 0.3, and 0.4) for the methane oxidation reaction was evaluated in terms of the iron content in the perovskite lattice. When the CH4/O2 ratio was 0.25, the total oxidation of methane was predominant. Methane oxidation started at 450ºC and increased with increasing temperature. The methane conversion rate strongly depended on the iron content. With higher iron content, the methane conversion rate was accordingly enhanced. This phenomenon may be attributed to the presence of oxygen vacancies in the perovskite lattice. At a CH4/O2 ratio=2, a partial oxidation reaction occurred at temperature above 750°C.

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Bond Energy Effects in Methane Oxidative Coupling on Pyrochlore Structures

Cited by 25 publications

References 0 publications

Catalytic Oxidation of Soot on a Novel Active Ca-Co Dually-Doped Lanthanum Tin Pyrochlore Oxide

Catalytic Oxidation of Soot on a Novel Active Ca-Co Dually-Doped Lanthanum Tin Pyrochlore Oxide

Catalytic combustion of soot particulates over rare-earth substituted Ln2Sn2O7 pyrochlores (Ln = La, Nd and Sm)

Catalytic activity of Y and Fe co-doped SrTio3 perovskites for methane oxidation

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