Séminaire LRS | Maco Altomare "Solid-state dewetting made useful: Model nanoparticle electrodes for electrocatalysis"

Supported metal nanoparticles are of wide scientific and technological interest. When coupled with conductive or semiconductor surfaces, they find application as catalysts in electro- and photo-catalytic reactions, or in plasmonics and sensing. Oxide supported-metal nanoparticles are at the core of most thermo-catalytic processes.
A straightforward and versatile, yet underexplored, way to produce supported metal particles is “solid-state dewetting” (hereafter, simply dewetting) [1], that is, the heat-induced agglomeration of thin metal films into defined nanoparticles well-attached onto a support. This occurs via surface diffusion of metal atoms at elevated temperatures, due to the metastable nature and high surface-to-volume ratio of thin metal films. The driving force is the minimization of the surface energy of the metal film and substrate, and of the metal/substrate interface.
Noteworthy, dewetting of thin films has long plagued makers of integrated circuits. It has also limited the reliability of other microdevices, especially when high-temperature operation is required, and much research has been carried out to characterize and suppress dewetting in all these systems [1]. In our research, we take a different perspective: we deliberately induce dewetting under controlled conditions as a design concept towards model nanoparticle platforms for electro- and photo-catalysis.
In my seminar, I will discuss the use of solid-state dewetting to control key properties of catalyst nanoparticles (size, composition, and structure) formed on electrodes and photocatalytic layers [2]. I will show how to enable nanoscale effects such as metal-support interactions to boost the catalyst performance in electrocatalytic reactions (e.g., hydrogen evolution) [3], and how tuning the catalyst composition affects catalyst stability and activity in photocatalysis [4,5]. In addition, I will show how dewetting can be steered to produce model nanocatalysts composed of ensembles of spatially-separated and uniformly-oriented metal nanoparticles with defined exposed facets [6].

[1] C.V. Thompson, Annu. Rev. Mater. Res. 2012, 42, 399
[2] M. Altomare et al., Chem. Sci. 2016, 7, 6865
[3] S. Harsha et al., Adv. Funct. Mater. 2024, 2403628
[4] D. Spanu et al., ACS Catal. 2020, 10, 15, 8293
[5] D. Spanu et al., ACS Catal. 2018, 8, 6, 5298
[6] R.K. Sharma et al., 2023 Meet. Abstr. MA2023-02 2059