Oxide-based nanomaterials for fuel cell catalysis: the interplay between supported single Pt atoms and particles. Issue 19 (19th June 2017)

• Record Type: Journal Article
• Authors: Lykhach, Yaroslava; Bruix, Albert; Fabris, Stefano; Potin, Valérie; Matolínová, Iva; Matolín, Vladimír; Libuda, Jörg; Neyman, Konstantin M.
• Is Part Of: Catalysis science & technology. Volume 7:Issue 19(2017)
• Page Start: 4315
• Page End: 4345
• Publication Date: 2017-06-19
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/c7cy00710h
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : Nanomaterials coated with atomically dispersed platinum on ceria are structurally dynamic and show high potential for applications in fuel cells. Abstract : The concept of single atom catalysis offers maximum noble metal efficiency for the development of low-cost 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 sub-nanometer 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 sub-nanometer 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.