Ce0.9Zr0.1O2 nanocatalyst: Influence of synthesis conditions in the reducibility and catalytic activity

Zimicz, Maria Genoveva; Lamas, Diego G.; Larrondo, Susana Adelina

doi:10.1016/j.catcom.2011.07.029

Cited by 23 publications

(19 citation statements)

References 17 publications

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“…Previous studies in our research group indicated that the mixed oxide with nominal composition Ce 0.9 Zr 0.1 O 2 is a great catalyst for total oxidation of methane, and excellent support of nickel metallic phase to catalyse partial oxidation of methane , . Moreover, when impregnated with Ni or Ni/Cu, this oxide resulted a great anode material for Intermediate Temperature Solid Oxide Fuel Cells (IT‐SOFCs) , …”

Section: Introductionmentioning

confidence: 89%

Ce_0.9Zr_0.1O₂Mixed Oxide Prepared by the Citrate Route: Impact of Synthesis Conditions on Physicochemical and Redox Properties

2020

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The aim of this work is to study the effect of the citric acid to metal molar ratio (CA/M) used in the citrate synthesis route on the structural, morphological and redox properties of CeO 2 -ZrO 2 mixed oxides. The CA/M ratio strongly affects reducibility, crystallite size and texture. The increase in calcination temperature promotes sample crystallinity while nanometric sizes remain up to 1000°C. H 2 -TPR, in situ dispersive X-ray absorption (DXAS) and Raman experiments show that samples [a] R.

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Section: Introductionmentioning

confidence: 89%

Ce_0.9Zr_0.1O₂Mixed Oxide Prepared by the Citrate Route: Impact of Synthesis Conditions on Physicochemical and Redox Properties

2020

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“…The feed to the reactor was a mixture of 2 mol% CH 4 :4 mol% O 2 and N 2 balance with a total volume flow of 333 cm 3 (STP)min −1 . These studies were previously reported and are presented here for comparison purposes 14 .…”

Section: Characterizationmentioning

confidence: 96%

“…Besides, carbon balance between feed and effluent was in the 100%±5% range with no observation of traces of carbon deposits in the scanning electron microscopy micrographs of the spent catalysts 14 . Figure 10.…”

Section: In Situ Xanes Experimentsmentioning

confidence: 99%

“…XANES experiments in methane oxidation conditions were conducted only for sample GS, due to the poor catalytic activity of sample LS previously observed in conventional catalytic tests 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 The only carbonated product detected in the effluent gas was carbon dioxide (CO 2 ).…”

Section: In Situ Xanes Experimentsmentioning

confidence: 99%

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XPD and XANES Studies of Ce_0.9Zr_0.1O₂ Nanocatalysts under Redox and Catalytic CH₄ Oxidation Conditions

et al. 2015

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The aim of this work is to take further insight into the structural stability of ceriumzirconium catalysts under reducing, oxidizing and reaction conditions. In situ synchrotron based techniques (XANES and XPD) were used in order to determine the stability of crystal structure and the oxidation state of cerium cations in the reaction conditions prevailing in the catalytic studies. In situ XPD studies in 5 mol% H 2 atmosphere revealed that no structural changes occur until 870°C. At this temperature, the sample synthesized with glycine, which presents lower crystallite agglomeration, segregated a small quantity of a reduced phase. On the contrary, the solid synthesized with lysine, with more agglomerated crystallites, does not show structural changes in all the temperature range.Reoxidation treatments in 5 mol % O 2 revealed that at 750°C the segregated phase disappears and the original cubic structure is restored.In situ XANES studies in the Ce L III absorption edge indicate that under catalytic reaction conditions, the degree of reduction of Ce 4+ is low, allowing the occurrence of methane oxidation. The solid is capable to deliver the oxygen of its structure when no oxygen is fed into the reactor until the 50 % of cerium cations become reduced, triggering the deactivation process. Therefore, it is clear for these studies that the Ce 4+ to Ce 3+ ratio in the lattice is governing the catalytic behaviour of the solid. The catalytic results collected during in situ XANES experiments are in excellent agreement with our previous catalytic studies performed with a laboratory fixed bed reactor.

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“…Mixed conductors (MIECs) with tailored micro/nano structure allowed optimizing both cathode and anode functions [2][3][4][5][6]. However, bulk material properties and interphase characteristics are decisive in the transfer of the oxygen ions and electrons through the cell and need to be investigated and optimized to increase the device performance and life time.…”

Section: Introductionmentioning

confidence: 99%

Review on Ceramic Interphases by Transmission and Scanning Electron Microscopy

Soldati

Montenegro-Hernández

Baqué

et al. 2014

Practical Metallography

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The Focused Ion Beam (FIB) technique was used to prepare site-specific samples from interfacial regions of different solid oxide fuel cells assemblies. Transmission and Scanning Electron Microscopy on the FIB foils combined with Electrochemical Impedance Spectroscopy (EIS) allowed the characterization of the electrode/electrolyte interphases and the determination of its influence on the cell performance after longterm operation conditions. This work reviews two cases: on one hand, Ln 2 NiO 4+δ (Ln= La, Nd) cathodes deposited on both Y 0.08 Zr 0.92 O 1.96 and Ce 0.9 Gd 0.1 O 1.95 electrolytes, that react at 900 °C during the adhesion treatment and at temperatures higher than 650 °C during the EIS measurements. These samples present a reaction layer of 10 nm thickness, which contains elements of both phases and was found responsible of the cell performance degradation. On the other hand, La 0.4 Sr 0.6 Co 0.8 Fe 0.2 O 3-δ cathodes showed excelent performance on Ceria electrolytes, even after 1000 hours at operation conditions. In that case, the microscopic analyses of FIB foils showed a semi-coherent interphase growth.

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Ce0.9Zr0.1O2 nanocatalyst: Influence of synthesis conditions in the reducibility and catalytic activity

Cited by 23 publications

References 17 publications

Ce_0.9Zr_0.1O₂Mixed Oxide Prepared by the Citrate Route: Impact of Synthesis Conditions on Physicochemical and Redox Properties

Ce_0.9Zr_0.1O₂Mixed Oxide Prepared by the Citrate Route: Impact of Synthesis Conditions on Physicochemical and Redox Properties

XPD and XANES Studies of Ce_0.9Zr_0.1O₂ Nanocatalysts under Redox and Catalytic CH₄ Oxidation Conditions

Review on Ceramic Interphases by Transmission and Scanning Electron Microscopy

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Ce0.9Zr0.1O2 nanocatalyst: Influence of synthesis conditions in the reducibility and catalytic activity

Cited by 23 publications

References 17 publications

Ce0.9Zr0.1O2Mixed Oxide Prepared by the Citrate Route: Impact of Synthesis Conditions on Physicochemical and Redox Properties

Ce0.9Zr0.1O2Mixed Oxide Prepared by the Citrate Route: Impact of Synthesis Conditions on Physicochemical and Redox Properties

XPD and XANES Studies of Ce0.9Zr0.1O2 Nanocatalysts under Redox and Catalytic CH4 Oxidation Conditions

Review on Ceramic Interphases by Transmission and Scanning Electron Microscopy

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Ce_0.9Zr_0.1O₂Mixed Oxide Prepared by the Citrate Route: Impact of Synthesis Conditions on Physicochemical and Redox Properties

Ce_0.9Zr_0.1O₂Mixed Oxide Prepared by the Citrate Route: Impact of Synthesis Conditions on Physicochemical and Redox Properties

XPD and XANES Studies of Ce_0.9Zr_0.1O₂ Nanocatalysts under Redox and Catalytic CH₄ Oxidation Conditions