Promotional Effect of Ag on the Catalytic Activity of Au for Glycerol Electrooxidation in Alkaline Medium

The potential of silver as an auxiliary metal for gold in the electrochemical oxidation of glycerol in alkaline medium is studied. Three bimetallic materials (Au3Ag/C, AuAg/C, and AuAg3/C) and the corresponding monometallic reference materials (Au/C and Ag/C) are prepared by chemical reduction of their precursors with glycerol. Half-cell measurements evidence the beneficial effect of Ag on the electrocatalytic activity of Au for glycerol oxidation owing to decreased onset potential and higher current density in chronoamperometry, with an optimum formulation of AuAg/C. These results are confirmed by the single-cell performance of AuAg/C, which, despite having half the Au loading, has a higher open-circuit voltage than Au/C and a similar maximum power density. The results are correlated with the structural and electronic features of these materials, which are widely discussed in other works.