Plasmonic sensing to follow the reactivity on Pt nanoparticles and clusters
Résumé
Understanding how gas molecules interact with nanoparticles (NPs) remains an essential challenge in the studies of atmospheric chemistry and catalytic reactions. When gas molecules interact with Pt NPs supported on Au nanodisks, they modify the local dielectric properties of the surrounding media. Such a modification induces a wavelength shift of the localized surface plasmon resonance (LSPR) of the Au nanodisks which can be easily detected by UV-Vis spectroscopy. This method is called indirect nanoplasmonic sensing (INPS).
CO and oxygen adsorption as well as CO oxidation on Pt NPs have been followed by INPS coupled with mass spectrometry [1]. We obtained a quantitative and very sensitive probe even for a very low Pt NPs coverage. We could detect the adsorption of gas molecules down to a few hundredths of a monolayer. Moreover, we can use nanoplasmonic sensing in a wide range of pressure (UHV to atmospheric pressure) and temperature. We present results obtained both on Pt nanocubes (3 nm) synthesized by wet chemistry [1] and on Pt10 clusters obtained by size-selected deposition on the nanoplasmonic sensor at the J. Heyrovsky Institute of Physical Chemistry. Lastly, FDTD calculations are performed to interpret LSPR spectra and to optimize the physical parameters of the plasmonic nanosensors.
References
1.B. Demirdjian, I. Ozerov, F. Bedu, A. Ranguis and C. R. Henry, ACS Omega 6 (2021) 13398
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