Effects of electron transfer in model catalysts composed of Pt nanoparticles on CeO2(1 1 1) surface

Kozlov, Sergey M.; Neyman, Konstantin M.

doi:10.1016/j.jcat.2016.10.014

Cited by 44 publications

(26 citation statements)

References 73 publications

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“…Here, the interatomic distance increased linearly with increasing the nanoparticle size approaching the bulk Pt value of 2.823 Å, which is in good agreement with our calculated bulk value of 2.805 Å and with the experimentally reported value of 2.775 Å [59]. The overestimation of the predicted value for the interatomic Pt-Pt distance in bulk Pt compared to the experimental value (by 0.048 Å) is typically observed in DFT calculations employing GGA functionals [55], which agrees well with previous theoretical works on scaling the properties of palladium nanoparticles [45,46], copper, gold, and silver nanoparticles [57]. Although the interatomic distance averaged over all atoms scales to the bulk values, the outer-shell atoms do not exhibit a clear tendency.…”

Section: Geometrical Featuressupporting

confidence: 92%

“…This long-range charge transfer scales with the work function difference between the support and the catalyst [41] and is also size-dependent [42]. However, theoretically, the charge transferred between the support and Pt-nanoparticles was quantified [42][43][44][45][46][47]. The effect of the charge transfer based on the work function difference between the SnO 2 supports, and Ptnanoparticles is scarce.…”

Section: Introductionmentioning

confidence: 99%

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The effect of SnO2(110) supports on the geometrical and electronic properties of platinum nanoparticles

2019

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While Pt-nanoparticles supported on SnO 2 exhibit improved durability, a substantial detriment is observed on the Ptnanoparticles' activity toward the oxygen reduction reaction. A density functional theory method is used to calculate isolated, SnO 2 -and graphene-supported Pt-nanoparticles. Work function difference between the Pt-nanoparticles and SnO 2 leads to electron donation from the nanoparticles to the support, making the outer-shell atoms of the supported nanoparticles more positively charged compared to unsupported nanoparticles. From an electrostatic point of view, nucleophilic species tend to interact more stably with less negatively charged Pt atoms blocking the active sites for the reaction to occur, which can explain the low activity of Pt-nanoparticles supported on SnO 2 . Introducing oxygen vacancies and Nb dopants on SnO 2 decreases the support work function, which not only reduces the charge transferred from the Pt-nanoparticles to the support but also reverses the direction of the electrons flow making the surface Pt atoms more negatively charged. A similar effect is observed when using graphene, which has a lower work function than Pt. Thus, the blocking of the active sites by nucleophilic species decreases, hence increasing the activity. These results provide a clue to improve the activity by modifying the support work function and by selecting a support material with an appropriate work function to control the charge of the nanoparticle's surface atoms. Graphic abstractKeywords Density functional theory · Platinum nanoparticles · SnO 2 · Support effect · Polymer electrolyte fuel cells Electronic supplementary material The online version of this article (https ://doi.org/10.1007/s4245 2-019-1478-0) contains supplementary material, which is available to authorized users.* Michihisa Koyama, koyama.michihisa@nims.go.jp |

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Section: Geometrical Featuressupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

The effect of SnO2(110) supports on the geometrical and electronic properties of platinum nanoparticles

2019

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“…At these particle sizes, the metal-support interaction is mostly associated with the restructuring of the particle shape and Pt/ceria interface which is rather insensitive to the charge transfer. 136 Density functional modeling rationalized the magnitude of the charge transfer, mainly depending on three parameters, i.e. the size of the Pt particles, their density, and the presence of oxygen vacancies 117 (Fig.…”

Section: Redox Coupling With the Reducing Agentmentioning

confidence: 99%

“…117,136 Small Pt aggregates in the sub-nanometer regime consist of only a few atomic layers and, therefore, most of their surface atoms bear an excess charge. This effect may be employed to modify the catalytic properties of the supported particles.…”

Section: 140mentioning

confidence: 99%

Oxide-based nanomaterials for fuel cell catalysis: the interplay between supported single Pt atoms and particles

Lykhach

Bruix

Fabris

et al. 2017

Catal. Sci. Technol.

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The concept of single atom catalysis offers maximum noble metal efficiency for the development of lowcost catalytic materials. Among possible applications are catalytic materials for proton exchange membrane fuel cells. In the present review, recent efforts towards the fabrication of single atom catalysts on nanostructured ceria and their reactivity are discussed in the prospect of their employment as anode catalysts.The remarkable performance and the durability of the ceria-based anode catalysts with ultra-low Pt loading result from the interplay between two states associated with supported atomically dispersed Pt and subnanometer Pt particles. The occurrence of these two states is a consequence of strong interactions between Pt and nanostructured ceria that yield atomically dispersed species under oxidizing conditions and sub-nanometer Pt particles under reducing conditions. The square-planar arrangement of four O atoms on {100} nanoterraces has been identified as the key structural element on the surface of the nanostructured ceria where Pt is anchored in the form of Pt 2+ species. The conversion of Pt 2+ species to subnanometer Pt particles is triggered by a redox process involving Ce 3+ centers. The latter emerge due to either oxygen vacancies or adsorption of reducing agents. The unique properties of the sub-nanometer Pt particles arise from metal-support interactions involving charge transfer, structural flexibility, and spillover phenomena. The abundance of specific adsorption sites similar to those on {100} nanoterraces determines the ideal (maximum) Pt loading in Pt-CeO x films that still allows reversible switching between the atomically dispersed Pt and sub-nanometer particles yielding high activity and durability during fuel cell operation.

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“…Several studies have already made significant contributions to such an understanding. 9,22,28,[33][34][35][36] To obtain further insights, in this work we have used first principles density functional theory (DFT) calculations to analyze the influence of surface excess electrons on the structure, energetics, and reactivity of Pt and Au atoms, dimers, and trimers adsorbed on the (101) surface of anatase TiO 2 . Besides being useful model systems for understanding the different behaviors of Pt and Au NPs on stoichiometric and reduced TiO 2 , such small clusters are currently of great interest in catalysis because of their unique properties and lower costs as well.…”

Section: Introductionmentioning

confidence: 99%

Effect of reducible oxide–metal cluster charge transfer on the structure and reactivity of adsorbed Au and Pt atoms and clusters on anatase TiO2

Wang

Selloni

2017

The Journal of Chemical Physics

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We carried out density functional theory calculations to study the influence of oxide-metal charge transfers on the structure, energetics, and reactivity of Au and Pt atoms, dimers, and trimers adsorbed on the (101) surface of reduced anatase TiO 2 . Pt clusters interact much more strongly with the TiO 2 support than Au clusters, and, with the exception of single Pt adatoms, generally behave as electron acceptors on reduced TiO 2 , whereas Au clusters can both accept and donate charge on the reduced surface. The reactivity of the supported clusters was probed by considering their interaction with CO and co-adsorbed O 2 . The effect of surface reduction on the interaction with CO is particularly significant when the CO adsorption site is an interfacial metal atom directly in contact with the TiO 2 surface and/or in the presence of co-adsorbed O 2 . Pt clusters interact strongly with co-adsorbed O 2 and form Pt-O 2 complexes that can easily accept electrons from reduced surfaces. In contrast, Au clusters donate charge to co-adsorbed O 2 even in the presence of excess electrons from a reduced support. The computed differences in the properties of the supported Pt and Au clusters are consistent with several experimental observations and highlight the important role of excess surface electrons in the behavior of supported metal catalysts on reducible oxides. Published by AIP Publishing. [http://dx

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Effects of electron transfer in model catalysts composed of Pt nanoparticles on CeO2(1 1 1) surface

Cited by 44 publications

References 73 publications

The effect of SnO2(110) supports on the geometrical and electronic properties of platinum nanoparticles

The effect of SnO2(110) supports on the geometrical and electronic properties of platinum nanoparticles

Oxide-based nanomaterials for fuel cell catalysis: the interplay between supported single Pt atoms and particles

Effect of reducible oxide–metal cluster charge transfer on the structure and reactivity of adsorbed Au and Pt atoms and clusters on anatase TiO2

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