Valence State Tuning of Gold Nanoparticles in the Dewetting Process: An X‑ray Photoelectron Spectroscopy Study

Gold nanoparticles (AuNPs) are commonly synthesized using the citrate reduction method, reducing Au3+ into Au1+ ions and facilitating the disproportionation of aurous species to Au atoms (Au0). This method results on citrate-capped AuNPs with valence single states Au0. Here, we report a methodology...

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Bibliographic Details
Published in:ACS omega 2022-09, Vol.7 (38), p.34521-34527
Main Authors: Lanza, Gustavo, Martinez Jimenez, Mawin J., Alvarez, Fernando, Perez-Taborda, Jaime Andres, Avila, Alba
Format: Article
Language:English
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Summary:Gold nanoparticles (AuNPs) are commonly synthesized using the citrate reduction method, reducing Au3+ into Au1+ ions and facilitating the disproportionation of aurous species to Au atoms (Au0). This method results on citrate-capped AuNPs with valence single states Au0. Here, we report a methodology that allows obtaining AuNPs by the dewetting process with three different valence states (Au3+, Au1+, and Au0), which can be fine-tuned with ion bombardment. The chemical surface changes and binding state of the NPs were investigated using core-level X-ray photoelectron spectroscopy (XPS). This is achieved by recording high-resolution Au 4f XPS spectra as a function of ion dose exposure. The results obtained show a time-dependent tuning effect on the Au valence states using low-energy 200 V acceleration voltage Ar+ ion bombardment, and the valence state conversion kinetics involves the reduction from Au3+ and Au1+ to Au0. Proper control of the reduction in the valence states is critical in surface engineering for controlling catalytic reactions.
ISSN:2470-1343
2470-1343
DOI:10.1021/acsomega.2c04259