Document Detail

Formation of Nanometer-sized Surface Platinum Oxide Clusters on a Stepped Pt(557) Single Crystal Surface Induced by Oxygen: A High-pressure STM and Ambient-pressure XPS Study.
MedLine Citation:
PMID:  22300373     Owner:  NLM     Status:  Publisher    
We studied the oxygen induced restructuring process on a stepped Pt(557) single crystal surface using high-pressure scanning tunneling microscopy (HP-STM) and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) at O2 pressures up to 1 torr. HP-STM has revealed that nanometer-sized clusters are created on Pt(557) at 1 torr of O2 and at room temperature. These clusters are identified as surface Pt oxide by AP-XPS. The appearance of clusters is preceded by the formation of 1-D chain structures at the step edges. By using a Pt(111) surface as a reference, it was found that the step sites are the nucleation centers for the formation of surface oxide clusters. These surface oxide clusters disappear and the stepped structure is restored on Pt(557) after evacuating O2 to 10-8 torr. Changes in the surface oxide concentration in response to variations in the O2 gas pressure are repeatable for several cycles. Our results that small clusters are initiated at step sites at high pressures demonstrate the importance of performing in-situ characterization of stepped Pt catalysts under reaction conditions.
Zhongwei Zhu; Franklin Feng Tao; Fan Zheng; Rui Chang; Yimin Li; Lars Heinke; Zhi Liu; Miquel Salmeron; Gabor A Somorjai
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-2-2
Journal Detail:
Title:  Nano letters     Volume:  -     ISSN:  1530-6992     ISO Abbreviation:  -     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-2-3     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101088070     Medline TA:  Nano Lett     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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