Au/C catalysts prepared by a green method towards C3 alcohol electrooxidation: A cyclic voltammetry and in situ FTIR spectroscopy study

• Au/C can be easily prepared by chemical reduction with glycerol.
• The electro-oxidation of C3 alcohols catalyzed by Au nanoparticles can lead to added value byproducts.
• The increasing in the activities are related with presence of vicinal OH groups are associated with C–C bond breaking.

Gold electrocatalysts seems to be an interesting material for application in Alkaline Fuel Cells (AFC) since several studies have reported the electro-catalytic activity of gold-based catalysts for various heterogeneous catalyzed oxidation reactions like oxidation of small organic molecules. In this paper, we synthesized Au nanoparticles (Au Nps) dispersed onto Vulcan carbon substrate using a straightforward glycerol method in order to study the pathway electro-oxidation of alcohols, like glycerol, 1,2-propanediol and 1-propanol in alkaline medium. TEM images showed a good dispersion of the gold nanoparticles on the carbon support and the particle mean size ranging from 3 to 14 nm. The structure of gold is face centered cubic (fcc) indicated by XRD and the metal loading was 18% evaluated by EDS technique. Cyclic voltammetry was mainly used to evaluate the electrochemical activity of the Au NPs towards the oxidative transformation of alcohols. Electrochemical results proved that Au/C Nps are more active to oxidize glycerol than 1,2-propanediol and 1-propanol, while higher current density was obtained for the diol. In situ FTIR measurements showed different pathway for each alcohol. For glycerol electro-oxidation, the mean byproducts from reaction were formate and oxalate ions. It was already suggested that gold in alkaline medium oxidized glycerol more promptly than others alcohols. The electro-oxidation of 1,2-propanediol leaded to acetate ion and hydroxyacetone while the in situ FTIR spectrum for electrooxidation of 1-propanol suggests that propanoate is the only the product of 1-propanol electro-oxidation over Au/C.