Squeezing out nanoparticles from perovskites : controlling exsolution with pressure

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López‐García, Andrés and Remiro‐Buenamañana, Sonia and Neagu, Dragos and Carrillo, Alfonso J. and Serra, José Manuel (2024) Squeezing out nanoparticles from perovskites : controlling exsolution with pressure. Small, 20 (47). 2403544. ISSN 1613-6810 (https://doi.org/10.1002/smll.202403544)

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Abstract

Nanoparticle exsolution has emerged as a versatile method to functionalize oxides with robust metallic nanoparticles for catalytic and energy applications. By modifying certain external parameters during thermal reduction (temperature, time, reducing gas), some morphological and/or compositional properties of the exsolved nanoparticles can be tuned. Here, it is shown how the application of high pressure (<100 bar H 2) enables the control of the exsolution of ternary FeCoNi alloyed nanoparticles from a double perovskite. H 2 pressure affects the lattice expansion and the nanoparticle characteristics (size, population, and composition). The composition of the alloyed nanoparticles could be controlled, showing a reversal of the expected thermodynamic trend at 10 and 50 bar, where Fe becomes the main component instead of Ni. In addition, pressure drastically lowers the exsolution temperature to 300 °C, resulting in unprecedented highly-dispersed and small-sized nanoparticles with a similar composition to those obtained at 600 °C and 10 bar. The mechanisms behind the effects of pressure on exsolution are discussed, involving kinetic, surface thermodynamics, and lattice-strain factors. A volcano-like trend of the exsolution extent suggests that competing pressure-dependent mechanisms govern the process. Pressure emerges as a new design tool for metallic nanoparticle exsolution enabling novel nanocatalysts and surface-functionalized materials.

ORCID iDs

López‐García, Andrés, Remiro‐Buenamañana, Sonia, Neagu, Dragos ORCID logoORCID: https://orcid.org/0000-0001-7208-1055, Carrillo, Alfonso J. and Serra, José Manuel;
CORE (COnnecting REpositories)