Oxygen Reduction on Silver Nanoparticles Supported on Carbide-Derived Carbons

Abstract

In this work carbide-derived carbons (CDC) are used as support for silver nanoparticles. The catalysts are studied by scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and the electrocatalytic activity of Ag/CDC catalysts for oxygen reduction reaction (ORR) and hydrogen peroxide reduction in alkaline solution is investigated using the rotating disk electrode (RDE) method. The SEM analysis revealed that the average Ag particle size is 15 nm and these are uniformly distributed over the catalyst material. TGA measurements show that the metal content in the catalyst is close to the nominal value of 40 wt%. The RDE results revealed that the ORR proceeds via a four-electron pathway to form OH−. The analysis of RDE data revealed that the mass-activity of Ag/CDC was about twice higher than that of Ag catalysts supported on Vulcan carbon. The Tafel analysis suggests that the slow transfer of the first electron to O2 molecule is the rate determining step for the ORR. The prepared Ag/CDC materials are also efficient catalysts for peroxide electroreduction.