A Highly Reactive and Sinter‐Resistant Catalytic System Based on Platinum Nanoparticles Embedded in the Inner Surfaces of CeO<sub>2</sub> Hollow Fibers

Yoon, Kyung Hoon; Yang, Yong; Lü, Ping; Wan, Dehui; Peng, Hsin‐Chieh; Stamm Masias, Kimber; Fanson, Paul T.; Campbell, Charles T.; Xia, Younan

doi:10.1002/anie.201203755

Cited by 126 publications

(98 citation statements)

References 33 publications

(32 reference statements)

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“…41−43 Moveover, it is also found that for CO oxidation, the Pt nanoparticles on CeO 2 can show very high activity with similar mechanistic features of some single-atomic metal catalysts, especially at low temperatures. 44,45 This is in agreement with the observations in literature that besides the size of Pt nanoparticles (or clusters), some other factors, such as valence distribution, surface morphology of ceria, and the oxygen defects of the support, can also influence the proportion of interfacial sites and the activity at relative low temperatures (30−80 °C), although the underlying reasons need to be clarified at the atomic level. 46−49 Herein, we demonstrate the strong effects of the local coordination structures of the subnanometric PtO x clusters over CeO 2 nanowires on their catalytic property in low-temperature CO oxidation as a probe reaction.…”

Section: Introductionsupporting

confidence: 90%

Strong Local Coordination Structure Effects on Subnanometer PtO_x Clusters over CeO₂ Nanowires Probed by Low-Temperature CO Oxidation

Ke¹,

Zhu²,

et al. 2015

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The fundamental understanding of the structural effects of supported metal catalysts at molecular level is extremely important for developing high-performance catalysts that are widely used in industry, which is still a long-standing attractive but challenging topic in multidisciplinary fields. In this work, we report the strong effects of local coordination structures on the catalytic activity of subnanometric PtO x clusters over CeO 2 nanowires in low-temperature CO oxidation as a probe reaction. Atoms and subnanometric clusters of Pt were deposited to form the coordination structure of PtO x on the well-defined CeO 2 nanowires with mainly exposing (110) facets. The reactivity of active sites and the variation of the local coordination structures of the PtO x sites were deeply investigated with in-situ spectroscopic experiments assisted by density functional theory simulations. According to our observation, although the highly dispersed Pt sites at subnanometric scale could provide increased accessible sites, some of the Pt sites could not show high activity for CO oxidation due to the increased surrounding oxygen that seemed to overstabilize the Pt atoms. An increased proportion of both adsorbed CO intermediates on oxidized Pt sites and the interfacial lattice oxygen of PtO x clusters tended to become inactive on the samples with high coordination number of oxygen bonded to Pt sites (CN(Pt−O)), leading to the loss of effective active sites and the decrease in the catalytic activity. A relative small CN(Pt−O) in the subnanometric PtO x /CeO 2 NWs, which was found to be the appropriate structures for their catalytic performances, could remarkably increase the activity by about half an order of magnitude. We believe our investigation on the interfacial coordination structures effects of the subnanometric PtO x clusters dispersed on CeO 2 nanowires can provide some new basic chemical insights into the metal-support interfacial interactions of Pt/CeO 2 catalysts for understanding their catalytic performance in some relevant reactions.

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Section: Introductionsupporting

confidence: 90%

Strong Local Coordination Structure Effects on Subnanometer PtO_x Clusters over CeO₂ Nanowires Probed by Low-Temperature CO Oxidation

Ke¹,

Zhu²,

et al. 2015

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“…Further thermal treatment leads to the separation of rigid preformed oxide shell and unreacted inner core. [69] Additionally, metal oxides (e.g., Cu 2 O) with various morphologies, such as cubic, octahedral, and dodecahedron, are especially suitable to work as templates to construct novel hollow CeO 2 structures with nonspherical morphologies. This highly controllable approach has been successfully applied to construct multishelled hollow spherical architectures in a number of metal oxides (e.g., α-Fe 2 O 3 , Co 3 O 4 , NiO, CuO, SnO 2 , and ZnO).…”

Section: Hard Templatementioning

confidence: 99%

Hollow Micro/Nanostructured Ceria‐Based Materials: Synthetic Strategies and Versatile Applications

Wang

2018

Advanced Materials

105

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Hollow micro/nanostructured CeO2‐based materials (HMNCMs) have triggered intensive attention as a result of their unique structural traits, which arise from their hollowness and the fascinating physicochemical properties of CeO2. This attention has led to widespread applications with improved performance. Herein, a comprehensive overview of methodologies applied for the synthesis of various hollow structures, such as hollow spheres, nanotubes, nanoboxes, and multishelled hollow spheres, is provided. The synthetic strategies toward CeO2 hollow structures are classified into three major categories: 1) well‐established template‐assisted (hard‐, soft‐, and in situ template) methods; 2) newly emerging self‐template approaches, including selective etching, Ostwald ripening, the Kirkendall effect, galvanic replacement, etc.; 3) bottom‐up self‐organized formation synthesis (namely, oriented attachment and self‐deformation). Their underlying mechanisms are concisely described and discussed in detail, the differences and similarities of which are compared transversely and longitudinally. Niche applications of HMNCMs in a wide range of fields including catalysis, energy conversion and storage, sensors, absorbents, photoluminescence, and biomedicines are reviewed. Finally, an outlook of future opportunities and challenges in the synthesis and application of CeO2‐based hollow structures is also presented.

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“…The core‐level XPS spectrum of elemental Pd (Figure d) was curve‐fitted into three doublets, including (i) peaks with BE values of 335.1 and 340.6 eV, which were attributed to Pd 3d 5/2 and Pd 3d 3/2 of Pd 0 ; (ii) peaks with BE values of 336.7 and 341.8 eV, which were attributed to the Pd 3d 5/2 and Pd 3d 3/2 forms of PdO; and (iii) peaks with BE values of 337.3 and 342.8 eV, which were assigned to the ionic state Pd 2+ originating from the ionic substitution of Pd 2+ for Ce 4+ in the CeO 2 lattice, suggesting that there were strong interactions with the CeO 2 shell in the form of Pd 2+ –O–Ce 4+ bonds . These results indicated that the bimetallic PdPt alloys were forming strong metal‐support interactions with the reactive CeO 2 shell, which would be beneficial for further improving their catalytic activity …”

Section: Resultsmentioning

confidence: 99%

Preparation of Magnetically Recyclable Yolk/Shell Fe_xO_y/PdPt@CeO₂ Nanoreactors with Enhanced Catalytic Activity

Yao

Guan

Zhang

et al. 2017

Chemistry An Asian Journal

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Noble metal nanoparticles (NPs) have recently received considerable attention from researchers working in the field of catalysis. However, the development of new methods allowing these materials to reach their maximum catalytic properties remains challenging. Nanoreactors could lead to dramatic improvements in activity with the help of the intrinsic confinement effect. In this study, we designed a series of yolk/shell Fe O /PdPt@CeO composites, where the Fe O NPs acted as a movable core, allowing for the uniform distribution of the PdPt alloys on the inner surface of the CeO shell. The high porosity and existence of hollow voids in the CeO shell allowed these Fe O /PdPt@CeO composites to be used as nanoreactors in catalytic reactions. As well this confinement effect, we identified two structural features that led to enhanced catalytic activity, including (i) the replacement of monometallic NPs with a bimetallic PdPt alloy and (ii) the replacement of a chemically inert support with a reactive CeO shell. The resulting nanoassembled catalysts displayed higher activities toward the catalytic reduction of dyes than the reference samples. Moreover, these catalysts were readily recovered and reused because of the magnetic Fe O core.

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A Highly Reactive and Sinter‐Resistant Catalytic System Based on Platinum Nanoparticles Embedded in the Inner Surfaces of CeO₂ Hollow Fibers

Cited by 126 publications

References 33 publications

Strong Local Coordination Structure Effects on Subnanometer PtO_x Clusters over CeO₂ Nanowires Probed by Low-Temperature CO Oxidation

Strong Local Coordination Structure Effects on Subnanometer PtO_x Clusters over CeO₂ Nanowires Probed by Low-Temperature CO Oxidation

Hollow Micro/Nanostructured Ceria‐Based Materials: Synthetic Strategies and Versatile Applications

Preparation of Magnetically Recyclable Yolk/Shell Fe_xO_y/PdPt@CeO₂ Nanoreactors with Enhanced Catalytic Activity

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A Highly Reactive and Sinter‐Resistant Catalytic System Based on Platinum Nanoparticles Embedded in the Inner Surfaces of CeO2 Hollow Fibers

Cited by 126 publications

References 33 publications

Strong Local Coordination Structure Effects on Subnanometer PtOx Clusters over CeO2 Nanowires Probed by Low-Temperature CO Oxidation

Strong Local Coordination Structure Effects on Subnanometer PtOx Clusters over CeO2 Nanowires Probed by Low-Temperature CO Oxidation

Hollow Micro/Nanostructured Ceria‐Based Materials: Synthetic Strategies and Versatile Applications

Preparation of Magnetically Recyclable Yolk/Shell FexOy/PdPt@CeO2 Nanoreactors with Enhanced Catalytic Activity

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A Highly Reactive and Sinter‐Resistant Catalytic System Based on Platinum Nanoparticles Embedded in the Inner Surfaces of CeO₂ Hollow Fibers

Strong Local Coordination Structure Effects on Subnanometer PtO_x Clusters over CeO₂ Nanowires Probed by Low-Temperature CO Oxidation

Strong Local Coordination Structure Effects on Subnanometer PtO_x Clusters over CeO₂ Nanowires Probed by Low-Temperature CO Oxidation

Preparation of Magnetically Recyclable Yolk/Shell Fe_xO_y/PdPt@CeO₂ Nanoreactors with Enhanced Catalytic Activity