The formation of interfacial metal–oxide structures on the Pt3Ni(111) bimetallic surface was investigated using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) techniques at near-ambient pressure (NAP). Direct observation of surface images clearly shows the occurrence of surface segregation of the sub-surface Ni depending on the surrounding gas-phase conditions. Especially, the prepared topmost Pt-skin layer of the Pt3Ni(111) is altered by Ni oxide segregation that makes an interfacial Pt-NiO1−x nanostructure with dissociated oxygen. This metal–oxide interface could provide active sites for more-efficient carbon monoxide (CO) conversion processes under mixed CO/O2 gas environments; the associated specific chemical binding energy was identified using NAP-XPS. The combined operando observations from the NAP-STM and NAP-XPS on the Pt3Ni(111) surface reveal that the interfacial metal–oxide structure is strongly correlated with the origin of the enhanced catalytic activity at thermodynamic equilibrium.
|ジャーナル||Journal of Electron Spectroscopy and Related Phenomena|
|出版ステータス||Published - 2020 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Physical and Theoretical Chemistry