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In Situ Monitoring of Non-Thermal Plasma Cleaning of Surfactant Encapsulated Nanoparticles

Authors :
Gengnan Li
Dmitri N. Zakharov
Sayantani Sikder
Yixin Xu
Xiao Tong
Panagiotis Dimitrakellis
Jorge Anibal Boscoboinik
Source :
Nanomaterials, Vol 14, Iss 3, p 290 (2024)
Publication Year :
2024
Publisher :
MDPI AG, 2024.

Abstract

Surfactants are widely used in the synthesis of nanoparticles, as they have a remarkable ability to direct their growth to obtain well-defined shapes and sizes. However, their post-synthesis removal is a challenge, and the methods used often result in morphological changes that defeat the purpose of the initial controlled growth. Moreover, after the removal of surfactants, the highly active surfaces of nanomaterials may undergo structural reconstruction by exposure to a different environment. Thus, ex situ characterization after air exposure may not reflect the effect of the cleaning methods. Here, combining X-ray photoelectron spectroscopy, in situ infrared reflection absorption spectroscopy, and environmental transmission electron microscopy measurements with CO probe experiments, we investigated different surfactant-removal methods to produce clean metallic Pt nanoparticles from surfactant-encapsulated ones. It was demonstrated that both ultraviolet-ozone (UV-ozone) treatment and room temperature O2 plasma treatment led to the formation of Pt oxides on the surface after the removal of the surfactant. On the other hand, when H2 was used for plasma treatment, both the Pt0 oxidation state and nanoparticle size distribution were preserved. In addition, H2 plasma treatment can reduce Pt oxides after O2-based treatments, resulting in metallic nanoparticles with clean surfaces. These findings provide a better understanding of the various options for surfactant removal from metal nanoparticles and point toward non-thermal plasmas as the best route if the integrity of the nanoparticle needs to be preserved.

Details

Language :
English
ISSN :
20794991
Volume :
14
Issue :
3
Database :
Directory of Open Access Journals
Journal :
Nanomaterials
Publication Type :
Academic Journal
Accession number :
edsdoj.130f0b52a6d24feb897618a79bc03977
Document Type :
article
Full Text :
https://doi.org/10.3390/nano14030290