Journal Article

PUBDB-2025-00003

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Spectro-Microscopy of Individual Pt–Rh Core–Shell Nanoparticles during Competing Oxidation and Alloying

Dwivedi, J. (Corresponding author)Extern*DESY* ; Bachmann, L. J. ; Jeromin, A. ; Kulkarni, S. ; Noei, H.DESY* ; Tănase, L. C. ; Tiwari, A. ; de Souza Caldas, L. ; Schmidt, T. ; Cuenya, B. R. ; Stierle, A.XFEL.EU*DESY* ; Keller, T. F. (Corresponding author)XFEL.EU*DESY*

2025
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/acsnano.5c07668  doi:10.3204/PUBDB-2025-00003

Abstract: The surface chemical composition of supported single Pt-Rh core-shell nanoparticles was studied to understand the Rh behavior in oxidizing and reducing gas environments using spectro-microscopy with high spatial resolution. We combined in situ X-ray photoemission electron microscopy with ex situ scanning electron-, atomic force- and scanning Auger-microscopy to distinguish Rh oxidation-reduction, dewetting-sintering and alloying-segregation during the course of the experiment. A more than 20% higher Rh 3d$_{5/2}$ oxide to metal photoemission intensity ratio for the Rh layer on top of the Pt-core was found as compared to the bare strontium titanate (STO) oxide catalyst support in close vicinity, where Rh/RhO$_x$ nanoparticles are forming. At elevated temperatures, Rh diffuses into the Pt particle, and this alloying at the Pt metal surface competes with the Rh oxidation, whereas the Rh/RhO$_x$ nanoparticles on the STO support are observed to sinter under identical oxidizing and temperature environments. A nanoparticle facet dependent analysis of selected Pt-core nanoparticles suggests that Rh oxidation is most advanced on a small nanoparticle with a low coordination top facet that we indexed by electron back scatter diffraction, demonstrating the strength of our correlative approach.

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Contributing Institute(s):

1. Nanolab (FS-NL)

Research Program(s):

1. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)
2. NEP - Nanoscience Foundries and Fine Analysis - Europe|PILOT (101007417) (101007417)
3. DFG project G:(GEPRIS)390540038 - EXC 2008: Unifying Systems in Catalysis "UniSysCat" (390540038) (390540038)

Experiment(s):

1. DESY NanoLab: Microscopy
2. DESY NanoLab: Sample Preparation

Appears in the scientific report 2025

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF >= 15 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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