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Strain and ligand effects in Pt-Ni alloys studied by valence-to-core X-ray emission spectroscopy.

ABSTRACT: Experimental detection of the Pt 5d densities of states in the valence band is conducted on a series of Pt-Ni alloys by high energy resolution valence-to-core X-ray emission spectroscopy (VTC-XES) at the Pt L₃-edge. VTC-XES measurements reveal that the Pt d-band centroid shifts away from the Fermi level upon dilution, accompanied by concentration-dependent Pt d-band width. The competition between the strain effect and ligand effect is observed experimentally for the first time. It is found that the d-band widths in Pt₃Ni and PtNi are broader than that of Pt metal due to compressive strain which overcompensates the effect of dilution, while it is narrower in PtNi₃ where the ligand effect dominates. VTC-XES is demonstrated to be a powerful tool to study the Pt d-band contribution to the valence band of Pt-based bimetallic. The implication for the enhanced activity of Pt-Ni catalysts in oxygen reduction reaction is discussed.

SUBMITTER: Chen J

PROVIDER: S-EPMC8249455 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature

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Strain and ligand effects in Pt-Ni alloys studied by valence-to-core X-ray emission spectroscopy.

Chen Jiatang J Finfrock Y Zou YZ Wang Zhiqiang Z Sham Tsun-Kong TK

Scientific reports 20210701 1

Experimental detection of the Pt 5d densities of states in the valence band is conducted on a series of Pt-Ni alloys by high energy resolution valence-to-core X-ray emission spectroscopy (VTC-XES) at the Pt L<sub>3</sub>-edge. VTC-XES measurements reveal that the Pt d-band centroid shifts away from the Fermi level upon dilution, accompanied by concentration-dependent Pt d-band width. The competition between the strain effect and ligand effect is observed experimentally for the first time. It is ...[more]

PMID: 34211031

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