Au/C catalysts promoted with metal oxides for ethylene glycol electro-oxidation in alkaline solution

Abstract

The Au-based catalysts on metal oxide (MexOy)-promoted carbon supports were prepared by polyvinyl alcohol (PVA) protection method and tested in ethylene glycol electro-oxidation. Three types of MexOy promoters, CeO2, Fe2O3 and RuO2, and different Au:MexOy weight ratios of 1:0.25, 1:0.5 and 1:1 were studied. Highly dispersed Au nanoparticles with the average particle sizes approximately 4nm were obtained for all the catalysts. The activity and stability of the catalysts towards ethylene glycol electro-oxidation in alkaline were investigated via cyclic voltammetry and chronoamperometry, respectively. It was found that the electrocatalytic properties of the promoted catalysts were affected by the type and the Au:MexOy ratio. Both types of Fe2O3- and RuO2-promoted catalysts yielded higher mass-normalized current density than the unpromoted Au/C. The most stable catalyst in a high mass-normalized current density region was Au–RuO2/C at Au:RuO2 ratio of 1:0.25. The RuO2-promoted catalysts were still active even in the potential region where the catalyst surface was fully covered by Au oxide film. In comparison with PtRu/C, the promoted Au catalysts generated higher mass-normalized current density.