Au101-rGO nanocomposite: immobilization of phosphine-protected gold nanoclusters on reduced graphene oxide without aggregation

Hanieh Mousavi, Yanting Yin, Liam Howard-Fabretto, Shailendra Kumar Sharma, Vladimir Golovko, Gunther G. Andersson, Cameron J. Shearer, Gregory F. Metha

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    Abstract

    Graphene supported transition metal clusters are of great interest for potential applications, such as catalysis, due to their unique properties. In this work, a simple approach to deposit Au101(PPh3)21Cl5(Au101NC) on reduced graphene oxide (rGO)viaanex situmethod is presented. Reduction of graphene oxide at native pH (pH ≈ 2) to rGO was performed under aqueous hydrothermal conditions. Decoration of rGO sheets with controlled content of 5 wt% Au was accomplished using only pre-synthesised Au101NC and rGO as precursors and methanol as solvent. High resolution scanning transmission electron microscopy indicated that the cluster size did not change upon deposition with an average diameter of 1.4 ± 0.4 nm. It was determined that the rGO reduction method was crucial to avoid agglomeration, with rGO reduced at pH ≈ 11 resulting in agglomeration. X-ray photoelectron spectroscopy was used to confirm the deposition of Au101NCs and show the presence of triphenyl phosphine ligands, which together with attenuated total reflectance Fourier transform infrared spectroscopy, advocates that the deposition of Au101NCs onto the surface of rGO was facilitatedvianon-covalent interactions with the phenyl groups of the ligands. Inductively coupled plasma mass spectrometry and thermogravimetric analysis were used to determine the gold loading and both agree with a gold loading ofca. 4.8-5 wt%. The presented simple and mild strategy demonstrates that good compatibility between size-specific phosphine protected gold clusters and rGO can prevent aggregation of the metal clusters. This work contributes towards producing an agglomeration-free synthesis of size-specific ligated gold clusters on rGO that could have wide range of applications.
    Original languageEnglish
    Pages (from-to)1422-1430
    Number of pages9
    JournalNanoscale Advances
    Volume3
    Issue number5
    DOIs
    Publication statusPublished - 7 Mar 2021

    Keywords

    • Graphene supported transition metal clusters
    • ex situ methods
    • Reduction of graphene oxide
    • aqueous hydrothermal conditions
    • X-ray photoelectron spectroscopy
    • triphenyl phosphine ligands

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