Silver–Palladium Electrodeposition on Unsupported Vulcan XC-72R for Oxygen Reduction Reaction in Alkaline Media

Carbon-supported Ag–Pd bimetallic nanocatalysts were successfully synthesized via the rotating disk slurry electrode (RoDSE) technique in a nominal precursor solution as a cost-effective means to improve oxygen reduction reaction (ORR) performance in fuel cell (FC) applications. Silver and palladium have both individually shown good catalytic activity. The work presented here compares three different electrodeposition methods using RoDSE, a robust electrodeposition method that allows the synthesis of highly dispersed Ag/Pd nanoparticles on Vulcan XC-72R, minimizing the catalyst preparation time. The electrochemical methods consist of (1) alternated, (2) sequential, and (3) simultaneous Ag and Pd electrodeposition on unsupported Vulcan XC-72R. Different characterization techniques such as TEM, XRD, ICP, and Raman spectroscopy were used to confirm the presence of Ag and Pd on the carbon substrate. The Ag/Pd face centered cubic crystal facets were determined by XRD with an approximate particle diameter of 23 nm for each electrochemical method. Performance of the catalysts was assessed for the ORR using cyclic voltammetry and rotating disk electrode techniques. Herein, we demonstrate that among the three methods of bimetallic Ag/Pd electrodeposition, an alternated approach yielded the best performance, measured using onset potential (Eonset), peak current density, and electron transfer in an alkaline media, in O2-saturated 0.1 M KOH.