Grand Séminaire d'Institut

Vendredi 30 Août 2024 à 11h00.

Light-Born Nanoparticles with Unusual Properties and their Application in Catalysis and Biomedicine

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Integration of the “nano-function” into products is still limited due to drawbacks of gas phase and chemical synthesis methods regarding particle aggregation and contamination by adsorbates causing deactivation of the building blocks ́ surface. In addition, thermodynamically controlled synthesis methods naturally face limited access to alloy nanoparticle systems with miscibility gaps. As an alternative synthesis route, nanoparticle generation by pulsed laser ablation in liquids has proven its capability to generate ligand-free colloidal nanoparticles with high purity and quite interesting surface chemistry, for a variety of materials.

In this talk, laser synthesis of colloids will be introduced, with examples of metal and alloy nanoparticles. Application of these laser-generated nanoparticles in heterogeneous catalysis as well as in biomedicine will be demonstrated. Good reproducibility and significant up-scaling of nanoparticle generation were achieved by a continuous flow synthesis using a high-power ultrafast laser system leading to productivities of up to 8 g/h colloidal nanoparticles, equivalent to kg-scale heterogeneous catalysts, or thousands of doses for biomedical application. Beyond that, the novel method of laser crushing of microparticle streams has even one order of magnitude higher energy efficiency, and is continuously producing ultrasmall nanoparticles at high yields.

Furthermore, alloy nanoparticles made of two up to seven elements (including high entropy alloys) were synthesized and their phase structure and surface chemistry are linked to their application potential. Interestingly, unusual nanoparticle properties difficult to access by conventional synthesis methods are yielded. The particle ́s functionality is linked to these unique properties, as will be exemplified for application in i) electrochemical water splitting benchmarked to the commercial standard, and ii) nano-sensitized proton therapy.

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