Characterization of gold nanoclusters deposited on HOPG by atmospheric plasma treatment

Abstract

The interest of gold nanoparticles in the field of nanocatalysis and nanosensors is growing. For example, carbon nanotubes covered with gold nanoclusters could present interesting properties in catalysis or/and in devices based on catalytic reaction such as chemical gas sensor. Unfortunately, the characterization of nanoparticles deposited onto a substrate is generally not a trivial exercise. Indeed, in many cases, the amount and size of material deposited is in the range of the sensitivity limits and the spatial resolutions of the techniques used. In that respect, our system, i.e. gold deposited onto a carbon support, is a favourable case, due to the high difference between the atomic numbers of gold and carbon.In this work, gold nanoparticles were deposited onto a HOPG (Highly Oriented Pyrolitic Graphite) substrate using an atmospheric plasma. In this preliminary study, HOPG sample has been used as a model surface that could present the same chemical properties as multiwall carbon nanotubes (MWCNTs).The surface composition was analysed using X-ray photoelectron spectroscopy (XPS). Narrow region electron spectra were used to extract the chemical-state information from the C 1s, O 1s and Au 4f peaks. The Au 4f spectral line shape was also analysed using the QUASES-Tougaard software package in order to obtain the in-depth concentration profile of the resulting nanomaterial. This result evidences a good agreement between experiment and modelling. Indeed, field emission scanning electron microscope (FE-SEM) and atomic force microscopy (AFM) images highlight a homogeneous distribution of 10 nm-size gold clusters with a surface coverage of 12% on the HOPG surface, both in agreement with the results obtained with the Tougaard and coworkers method.

Nanoscience with non-equilibrium plasmas at atmospheric pressure

“…A similar principle is used for the synthesis of cadmium oxide nanocubes [143]. Particles of noble metals (Au [144] and Pt [145]) were produced using a rf plasma [144] and an AC plasma with a liquid electrode used to easily collect the particles [145]. Polymeric nanoparticles have been produced from PTFE precursor [59], siloxane [146] and furan [147].…”

Fuel Cell Electrodes From Organometallic Platinum Precursors: An Easy Atmospheric Plasma Approach

“…Previous articles from our group [27][28][29][30] reported the deposition of metal nanoparticles (Rh, Au, Pt, . .…”

“…Previous articles from our group reported the deposition of metal nanoparticles (Rh, Au, Pt, …) on carbon substrates (carbon nanotubes, HOPG, glassy carbon) by spraying a colloidal solution in the flowing post‐discharge of a radio‐frequency (RF) atmospheric plasma torch. The use of an atmospheric plasma torch enables to obtain the surface activation and the surface decoration in “one single step,” contrarily to most of the techniques dedicated to the deposition of metallic nanoparticles on carbon supports.…”

The 2p3/2 binding energy shift of Fe surface and Fe nanoparticles

“…X-ray photoelectron spectroscopy (XPS) is a widely used tool for studying the band structure of surfaces and NPs [15][16][17][18]. From the spectra of XPS, the broad peaks of core-level binding energies (BE) can be obtained, which is mainly contributed from the intraatomic trapping potential V atom , and inter-atomic binding or crystal potential, V cry , and is represented in the form of components ascribed as surface layers and bulk.…”