Mono and bi-metallic electrocatalysts of Pt and Ag for oxygen reduction reaction synthesized by sonication

• Mono and bi-metallic nanoparticles were synthesized by sonication.
• Pt and Ag were synthesized with non-thermal treatments or surfactants.
• Pt–Ag exhibits better electrochemical activity for ORR compared to Pt.
• The role of Ag can be addressed as co-catalyst of Pt for the ORR.

Nanoparticles of Ag, Pt and Pt–Ag were synthesized using ultrasonic irradiation with no consecutive thermal treatment to catalyze the oxygen reduction reaction. Metal nanoparticles are supported on carbon substrate. The synthesized materials were characterized by XRD, TEM, and cyclic and lineal voltammetry techniques. The kinetic formation of the metallic nanoparticles in solution was followed using UV–vis spectroscopy. The metal particles have crystalline structure and particle size with < 10 nm in size and in the form of spherical agglomerates. Ag/C exhibits lower electrochemical activity and stability for the ORR compared to Pt/C and Pt–Ag/C in acid medium. The mass and specific activity results demonstrate that the synthesized bimetallic sample exhibits 1.5 and 5 times greater electrochemical activities for the ORR compared to the commercial sample.