Modification of Ag nanoparticles/reduced graphene oxide nanocomposites with a small amount of Au for glycerol oxidation

The surface modification of Ag nanoparticles supported on reduced graphene oxide (RGO) with a small amount of Au and the activity of Au-modified Ag/RGO (Au-Ag/RGO) catalysts for the electrooxidation of glycerol have been investigated. The deposition of Au on Ag/RGO nanocomposites was performed electrochemically, and the Au-Ag/RGO catalysts with Au:Ag atomic ratios in a range from 1:303 to 1:43 were prepared. The characterization of catalysts reveals a partial coverage of the Ag nanoparticle surface by Au adatoms. Cyclic voltammetric measurements indicate that the Au-Ag/RGO catalysts show almost the same activity as Au/RGO in terms of the geometric surface area of glassy carbon substrates for glycerol oxidation in alkaline solution, while Ag/RGO shows no catalytic activity. The Au-Ag/RGO catalysts have great advantages over Au/RGO in terms of the Au mass specific activity. A significant improvement in the catalytic activity of Ag/RGO by the deposition of a small amount of Au and a high utilization of Au are achieved, and the result is of significance for preparing highly active catalysts at low cost by using less expensive metal and active metal.