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Surface segregation and oxidation of Pt3Ni(1 1 1) alloys under oxygen environment

Paper ID Volume ID Publish Year Pages File Format Full-Text
53352 46964 2016 5 PDF Available
Title
Surface segregation and oxidation of Pt3Ni(1 1 1) alloys under oxygen environment
Abstract

•With ambient pressure XPS, the oxidation states of Pt3Ni(1 1 1) surface are measured in in situ.•Under elevated oxygen pressure, Ni atoms segregate to surface and form surface oxide.•Pt skin layer is stable under UHV condition.

Utilizing ambient pressure X-ray photoelectron spectroscopy (AP-XPS), the surface segregation and oxidation of Pt3Ni(1 1 1) alloys are investigated as a function of temperature and oxygen pressure. The in situ AP-XPS measurements of oxygen oxidation process show that the Pt “skin” surface is not stable under the exposure of oxygen pressure of 100 mTorr at room temperature. As the temperature and pressure are elevated, the formations of Ni2O3, NiOx, and NiO are observed on surface while Pt atom starts to reduce its adsorbed oxygen, which is a clear sign of surface segregation of Ni to surface. Upon the evacuation of oxygen gas, i.e. ultrahigh vacuum condition, both of NiOx and NiO oxide get reduced and Ni2O3 remains on the surface. The DFT calculation is employed to explain the formation of surface oxides under oxidation condition.

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Keywords
Ambient pressure XPS; Pt alloys; Metal oxidation; DFT; Surface segregation
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Surface segregation and oxidation of Pt3Ni(1 1 1) alloys under oxygen environment
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 260, 1 February 2016, Pages 3–7
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us