Towards stable single-atom catalysts: strong binding of atomically dispersed transition metals on the surface of nanostructured ceria

Figueroba, Alberto; Kovács, Gâbor; Bruix, Albert; Neyman, Konstantin M.

doi:10.1039/c6cy00294c

Cited by 98 publications

(76 citation statements)

References 71 publications

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“…It seems important that the catalytic activity in this case sharply drops, and CO oxidation is not observed at temperatures below 100 °C, which is typical of Pt/CeO 2 samples in which platinum is only in the Pt 2+ state. It was noted that Pt 2+ ions interact with the CeO 2 surface to produce strong and stable Pt 2+ –O 4 complexes, which can hardly ensure the low‐temperature oxidation of CO. The oxide PtO x species can interact with ceria and be encapsulated by the upper layers of ceria, as was demonstrated by Mullins and Zhang .…”

Section: Discussionmentioning

confidence: 99%

Transformation of a Pt–CeO₂ Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

et al. 2018

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The pulsed laser ablation (PLA) in alcohol and water media was employed to prepare Pt and CeO2 PLA‐nanoparticles of different sizes and degrees of defectiveness. Interactions of metallic platinum and ceria particles were studied using the thermal activation of Pt–CeO2 mechanical mixtures in the CO+O2 reaction medium or O2 atmosphere. The thermal activation resulted in oxidized Pt2+/Pt4+ states of platinum in the surface solid solutions PtCeOx and/or PtOx clusters. Catalysts formed after calcination of the PLA‐ablated Pt–CeO2 mixtures in oxygen at 450–600 °C revealed CO conversion at very low temperatures up to 70 % depending on the conditions of PLA particles preparation and thermal activation of Pt–CeO2 mechanical mixture.

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Section: Discussionmentioning

confidence: 99%

Transformation of a Pt–CeO₂ Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

et al. 2018

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“…Many studies have been reported recently on this topic . For instance, a recent investigation has shown the capability of CeO 2 (1 0 0) to bind highly dispersed single transition metal atoms from groups VIII–X . Jones et al.…”

Section: Introductionmentioning

confidence: 99%

Nature of Sintering‐Resistant, Single‐Atom Ru Species Dispersed on Zirconia‐Based Catalysts: A DFT and FTIR Study of CO Adsorption

et al. 2018

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Recent studies on the upgrade of cellulosic biomass to renewable chemicals and fuels based on Ru/ZrO2 catalysts have shown that the catalyst contains atomically dispersed, highly stable Ru atoms. FTIR spectra after CO dosage reveal a complex manifold of bands resulting from Ru‐CO carbonyl species. The nature of the atomically dispersed Ru species on monoclinic zirconia, and the origin of their thermal stability are the object of this investigation. Combining density functional theory (DFT) calculations on model systems of both tetragonal and monoclinic ZrO2, with novel experimental data, we provide a basis for the identification of the monoatomic Ru species. Various candidates are explored based on DFT calculations of their intrinsic stability and of the vibrational properties of adsorbed CO probe molecules. The results allow us to discard a number of possible structures, and restrict the analysis to a few potential candidates. Most likely, the atomically dispersed sites result from the interaction of Ru atoms with one OH group of the surface with elimination of H2 by condensation, leaving RuO species strongly bound to the zirconia surface. CO binds strongly to the RuO units forming (RuO)(CO)2 geminal complexes with characteristic signatures in terms of CO vibrational frequency. Despite the formal positive oxidation state of the Ru species, large negative shifts are found in the CO stretching frequency compared with the free CO molecule.

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“…In this respect, the adsorption of metal atoms (M) including the 3d (Fe, Co, Ni, Cu), 4d (Ru, Rh, Pd, Ag) and 5d (Os, Ir, Pt, Au) metals of groups 8-10 was investigated. 82 The calculated adsorption energies are shown in Fig. 8 Clear trends emerge along the rows and groups of the periodic table (Fig.…”

Section: Parameters Controlling Proton Exchange Membrane Fuel Cell Pementioning

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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Towards stable single-atom catalysts: strong binding of atomically dispersed transition metals on the surface of nanostructured ceria

Abstract: Surface oxygen sites on CeO2 nanostructures are able to bind atoms of various transition metals strong enough to prevent their sintering. This finding opens a knowledge-driven way to prepare stable single-atom catalysts with maximum metal efficiency.

Cited by 98 publications

References 71 publications

Transformation of a Pt–CeO₂ Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

Transformation of a Pt–CeO₂ Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

Nature of Sintering‐Resistant, Single‐Atom Ru Species Dispersed on Zirconia‐Based Catalysts: A DFT and FTIR Study of CO Adsorption

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

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Towards stable single-atom catalysts: strong binding of atomically dispersed transition metals on the surface of nanostructured ceria

Abstract: Surface oxygen sites on CeO2 nanostructures are able to bind atoms of various transition metals strong enough to prevent their sintering. This finding opens a knowledge-driven way to prepare stable single-atom catalysts with maximum metal efficiency.

Cited by 98 publications

References 71 publications

Transformation of a Pt–CeO2 Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

Transformation of a Pt–CeO2 Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

Nature of Sintering‐Resistant, Single‐Atom Ru Species Dispersed on Zirconia‐Based Catalysts: A DFT and FTIR Study of CO Adsorption

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

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Transformation of a Pt–CeO₂ Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

Transformation of a Pt–CeO₂ Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation