Origin of Enhanced Reducibility/Oxygen Storage Capacity of Ce1-xTixO2 Compared to CeO2 or TiO2

Dutta, Gargi; Waghmare, Umesh V.; Baidya, Tinku; Hegde, M. S.; Priolkar, K. R.; Sarode, P. R.

doi:10.1021/cm060267i

Cited by 176 publications

(112 citation statements)

References 23 publications

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“…[49][50][51] It is generally accepted that, for example, the increase in OSC of Zr and Ti doped CeO 2 can be explained by the weakening of oxygen bonds around the dopant ion, 50,51 with a recent study highlighting the role of relaxation around the dopant in Zr doped CeO 2 . 52 Our calculations indicate that another significant factor is the preferred coordination environment of the dopant, especially in the case of d block transition metals.…”

Section: Discussionmentioning

confidence: 99%

The origin of the enhanced oxygen storage capacity of Ce1−x(Pd/Pt)xO2

Scanlon

Morgan

Watson

2011

Phys. Chem. Chem. Phys.

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Doping CeO 2 with Pd or Pt increases the oxygen storage capacity (OSC) and catalytic activity of this environmentally important material. To date, however, an understanding of the mechanism underlying this improvement has been lacking. We present a density functional theory analysis of Pd-and Pt-doped CeO 2 , and demonstrate that the increased OSC is due to a large displacement of the dopant ions from the Ce lattice site. Pd(II)/Pt(II) (in a d 8 configuration)moves by B1.2 Å to adopt a square-planar coordination due to crystal field effects. This leaves three three-coordinate oxygen atoms that are easier to remove, and which are the source of the increased OSC. These results highlight the importance of rationalizing the preferred coordination environments of both dopants and host cations when choosing suitable dopants for next generation catalysts.

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Section: Discussionmentioning

confidence: 99%

The origin of the enhanced oxygen storage capacity of Ce1−x(Pd/Pt)xO2

Scanlon

Morgan

Watson

2011

Phys. Chem. Chem. Phys.

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“…As a result, transition metal dopants are expected to produce the largest distortions, which is confi rmed by high-temperature cycles using H 2 as a reducing agent. [ 42 ] However, under these conditions the dopant ions can also be reduced. [ 41b,43 ] Although the reduced dopants can (at least initially) increase H 2 production in a WS thermochemical cycle, not all dopants can be fully reoxidized.…”

Section: Doped Ceriamentioning

confidence: 99%

Considerations in the Design of Materials for Solar‐Driven Fuel Production Using Metal‐Oxide Thermochemical Cycles

Miller

McDaniel

Allendorf

2013

Advanced Energy Materials

166

146

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With demand for energy increasing worldwide and an ever‐stronger case building for anthropogenic climate change, the need for carbon‐neutral fuels is becoming an imperative. Extensive transportation infrastructure based on liquid hydrocarbon fuels motivates development of processes using solar energy to convert CO2 and H2O to fuel precursors such as synthesis gas. Here, perspectives concerning the use of solar‐driven thermochemical cycles using metal oxides to produce fuel precursors are given and, in particular, the important relationship between reactor design and material selection is discussed. Considering both a detailed thermodynamic analysis and factors such as reaction kinetics, volatility, and phase stability, an integrated analytical approach that facilitates material design is presented. These concepts are illustrated using three oxide materials currently receiving considerable attention: metal‐substituted ferrites, ceria, and doped cerias. Although none of these materials is “ideal,” the tradeoffs made in selecting any one of them are clearly indicated, providing a starting point for assessing the feasibility of alternative materials developed in the future.

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“…[6][7][8][9][10][11][12][13][14][15][16][17] The reactivity of ceria in oxidation reactions, include CO oxidation [18][19][20] and NO X reduction [21][22][23][24][25] is intertwined with the release and uptake of oxygen. Doping of ceria with other metal cations, such as Zr, La, Pd, Ti and Cu has been widely studied [26][27][28][29][30][31][32][33][34][35][36][37][38] to enhance reactivity in oxidation reactions. Also, catalysts based on mixed MgO-CeO 2 supports and Mg doping have been proposed for many different reactions.…”

Section: Q2mentioning

confidence: 99%

On the interaction of Mg with the (111) and (110) surfaces of ceria

Nolan

Lykhach

Tsud

et al. 2012

Phys. Chem. Chem. Phys.

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Access to the full text of the published version may require a subscription. Please note that, in the typefaces we use, an italic vee looks like this: n, and a Greek nu looks like this: n. RightsWe will publish articles on the web as soon as possible after receiving your corrections; no late corrections will be made.Please return your final corrections, where possible within 48 hours of receipt, by e-mail to: pccp@rsc.org.Reprints-Electronic (PDF) reprints will be provided free of charge to the corresponding author. The catalytic activity of cerium dioxide can be modified by deposition of alkaline earth oxide layers or nanoparticles or by substitutional doping of metal cations at the Ce site in ceria. In order to understand the effect of Mg oxide deposition and doping, a combination of experiment and first principles simulations is a powerful tool. In this paper, we examine the interaction of Mg with the ceria (111) surface using both angle resolved X-ray (ARXPS) and resonant (RPES) photoelectron spectroscopy measurements and density functional theory (DFT) corrected for onsite Coulomb interactions (DFT + U). With DFT + U, we also examine the interaction of Mg with the ceria (110) (111) surface. The combined results provide a basis for deeper insights into the catalytic behaviour of ceria-based mixed oxide catalysts.

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Origin of Enhanced Reducibility/Oxygen Storage Capacity of Ce₁_-_xTi_xO₂ Compared to CeO₂ or TiO₂

Cited by 176 publications

References 23 publications

The origin of the enhanced oxygen storage capacity of Ce1−x(Pd/Pt)xO2

The origin of the enhanced oxygen storage capacity of Ce1−x(Pd/Pt)xO2

Considerations in the Design of Materials for Solar‐Driven Fuel Production Using Metal‐Oxide Thermochemical Cycles

On the interaction of Mg with the (111) and (110) surfaces of ceria

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