RuO2 promoted Au/C catalysts for alkaline direct alcohol fuel cells

RuO2 promoted Au/C catalysts at different Au:RuO2 ratios (1:0.25, 1:0.5 and 1:1) were prepared and investigated for their catalytic activity and stability for glycerol and ethanol electrooxidation in alkaline solution. The average size of Au nanoparticles on RuO2/C was around 4.1 ± 0.82 nm, which was slightly larger than that of Au/C. The electroactive surface areas of all the promoted catalysts decreased as Au:RuO2 increased and were lower than that of Au/C. The catalytic activity of Au/C was clearly enhanced by RuO2, as evaluated by cyclic voltammetry in which the current obtained from the ethanol oxidation on the promoted catalyst containing Au:RuO2 at 1:0.25 was about two times higher than that on Au/C. In addition, it was observed that the RuO2-promoted Au/C catalysts had higher stability for glycerol electrooxidation as determined by chronoamperometry. The increased stability of Au–RuO2/C catalysts in glycerol electrooxidation might derive from the ability of RuO2 to supply the oxygen-containing species to react with the reaction intermediates on Au surface.