Ceria nanoclusters on graphene/Ru(0001): A new model catalyst system

SURFACE SCIENCE

卷:652

Article

Novotny, Z.^1,2  Netzer, F. P.³  Dohnalek, Z.^1,2 

[1] Pacific Northwest Natl Lab, Phys & Computat Sci Directorate, Richland, WA 99354 USA

[2] Pacific Northwest Natl Lab, Inst Interfacial Catalysis, Richland, WA 99354 USA

[3] Karl Franzens Univ Graz, Inst Phys, Surface & Interface Phys, A-8010 Graz, Austria

关键词: Ceria;    CeO2;    Nanoclusters;    Graphene;    Ru(0001);    Smoluchowski ripening;    STM;    AES;   

DOI  :  10.1016/j.susc.2016.03.020

来源: Elsevier

【 摘 要 】

The growth of ceria nanoclusters on single-layer graphene on Ru(0001) has been examined, with a view towards fabricating a stable system for model catalysis studies. The surface morphology and cluster distribution as a function of oxide coverage and substrate temperature has been monitored by scanning tunneling microscopy (STM), whereas the chemical composition of the cluster deposits has been determined by Auger electron spectroscopy (AES). The ceria nanoparticles are of the CeO2(111)-type and are anchored at the intrinsic defects of the graphene surface, resulting in a variation of the cluster densities across the macroscopic sample surface. The ceria clusters on graphene display a remarkable stability against reduction in ultrahigh vacuum up to 900 K, but some sintering of clusters is observed for temperatures >450 K. The evolution of the cluster size distribution suggests that the sintering proceeds via a Smoluchowski ripening mechanism, i.e. diffusion and aggregation of entire clusters. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

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