Gas-Phase Deposition of Gold Nanoclusters to Produce Heterogeneous Glycerol Oxidation Catalysts

Rongsheng Cai,Graham J Hutchings,Grazia Malta,Richard E Palmer,Simon J Freakley,Sarah J Haigh

doi:10.1021/acsanm.0c01140

Abstract

Gold nanoparticles prepared by colloidal methods are effective catalysts for selective glycerol oxidation under basic conditions. Large-scale synthesis of catalysts by wet chemical methods leads to large amounts of waste and can result in polymer or salt residues remaining on the catalyst. In contrast, gas-phase cluster deposition (cluster beam deposition) offers a solvent-free method to synthesize controlled nanoparticles/clusters. We show that the deposition of bare gas-phase gold clusters onto carbon powder leads to a catalyst comparable to that prepared by colloidal methods. This shows the feasibility of the synthesis method to produce oxidation catalysts with reduced waste.

Highlights

Gold nanoparticles prepared by colloidal methods are effective catalysts for selective glycerol oxidation under basic conditions
Supported gold nanoparticles prepared by wet chemical methods, such as incipient-wetness impregnation and deposition precipitation, can be effective catalysts for glycerol
The 1 wt % Au/C prepared by colloidal methods on a 2 g scale was characterized by scanning transmission electron microscopy (STEM) in high-angle annular dark-field (HAADF) mode, which shows gold nanoparticles on the carbon support with a mean particle size of 2.7 ± 0.8 nm, as seen in Figure 1, and is consistent with previous reports.[10]

Summary

Introduction

Gold nanoparticles prepared by colloidal methods are effective catalysts for selective glycerol oxidation under basic conditions. (a) Reaction Scheme Showing Possible Glycerol Oxidation Pathways and Schematic Representations of Catalyst Fabrication Methods via (b) Immobilization of Gold Colloids and (c) CBD An alternative method to produce catalysts containing metal nanoparticles (2−5 nm) is the immobilization of colloidal gold particles onto activated carbon (Scheme 1b).

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Conclusion