Enhanced oxygen reduction activity of bimetallic Pd–Ag alloy-supported on mesoporous cerium oxide electrocatalysts in alkaline media

Abstract

Currently, the rational design and fabrication of Pt-free electrocatalysts towards the oxygen reduction reaction for extensive applications in fuel cells is a challenging task. Because of the exorbitant price of Pt-based catalysts, extensive commercialization is hindered. Herein, we report a Pd–Ag alloy-supported on mesoporous cerium oxide (meso-CeO₂) catalyst with excellent electrocatalytic activity and stability for the oxygen reduction reaction (ORR) under alkaline conditions. The improved ORR activity of Pd₃Ag₁/meso-CeO₂ originates from the high surface area of meso-CeO₂. Pd–Ag alloy (20 wt%) was decorated on the surface of meso-CeO₂ and it offers a larger number of active sites for electrocatalytic reactions. The synthesized Pd₃Ag₁/meso-CeO₂ shows comparable ORR activity with 20% Pt/C catalyst and good cycling stability in an alkaline medium, making it a universal Pt-metal free electrocatalyst for practical applications in fuel cells.