Volume 236, 2022

Evolution of surface and sub-surface morphology and chemical state of exsolved Ni nanoparticles

Abstract

Nanoparticle formation by dopant exsolution (migration) from bulk host lattices is a promising approach to generate highly stable nanoparticles with tunable size, shape, and distribution. We investigated Ni dopant migration from strontium titanate (STO) lattices, forming metallic Ni nanoparticles at STO surfaces. Ex situ scanning probe measurements confirmed the presence of nanoparticles at the H2 treated surface. In situ ambient pressure X-ray photoelectron spectroscopy (AP-XPS) revealed reduction from Ni2+ to Ni0 as Ni dopants migrated to the surface during heating treatments in H2. During Ni migration and reduction, the Sr and Ti chemical states were mostly unchanged, indicating the selective reduction of Ni during treatment. At the same time, we used in situ ambient pressure grazing incidence X-ray scattering (GIXS) to monitor the particle morphology. As Ni migrated to the surface, it nucleated and grew into compressed spheroidal nanoparticles partially embedded in the STO perovskite surface. These findings provide a detailed picture of the evolution of the nanoparticle surface and subsurface chemical state and morphology as the nanoparticles grow beyond the initial nucleation and growth stages.

Graphical abstract: Evolution of surface and sub-surface morphology and chemical state of exsolved Ni nanoparticles

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
18 Dec 2021
Accepted
04 Mar 2022
First published
11 May 2022
This article is Open Access
Creative Commons BY license

Faraday Discuss., 2022,236, 141-156

Evolution of surface and sub-surface morphology and chemical state of exsolved Ni nanoparticles

H. Kersell, Moritz L. Weber, L. Falling, Q. Lu, C. Baeumer, N. Shirato, V. Rose, C. Lenser, F. Gunkel and S. Nemšák, Faraday Discuss., 2022, 236, 141 DOI: 10.1039/D1FD00123J

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