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arXiv · 1811.06900

Ensemble versus Local Restructuring of Core-shell Nickel-Cobalt Nanoparticles upon Oxidation and Reduction Cycles

Sophie Carenco·Cecile S. Bonifacio·Judith C. Yang
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Abstract

Bimetallic nanoparticles are widely studied, for example in catalysis. However, possible restructuring in the environment of use, such as segregation or alloying, may occur. Taken individually, state-of-the-art analytical tools fail to give an overall picture of these transformations. This study combines an ensemble analysis (near-ambient-pressure X-ray photoelectron spectroscopy) with a local analysis (environmental transmission electron microscopy) to provide an in situ description of the restructuring of core--shell nickel-cobalt nanoparticles exposed to cycles of reduction and oxidation. It reveals a partial surface alloying accompanied by fragmentation of the shell into smaller clusters, which is not reversible. Beyond this case study, the methodology proposed here should be applicable in a broad range of studies dealing with the reactivity of mono- or bi-metallic metal nanoparticles.

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Sophie Carenco, Cecile S. Bonifacio, Judith C. Yang. 2018-11-16. Ensemble versus Local Restructuring of Core-shell Nickel-Cobalt Nanoparticles upon Oxidation and Reduction Cycles. https://doi.org/10.1002/chem.201802764

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