Synthesis of palladium-rare earth alloy as a high-performance bifunctional catalyst for direct ethanol fuel cells

Abstract

Direct ethanol fuel cells (DEFCs) have drawn attention for their simplicity, rapid start-up, high power density and environmental friendliness. Despite these advantages, the widespread application of DEFCs faces challenges, primarily due to the inadequate performance of anode and cathode catalysts. Pd-based materials have shown exceptional catalytic activity for both the ethanol oxidation reaction (EOR) and the oxygen reduction reaction (ORR). Alloying noble metals with rare earth elements has emerged as an effective strategy to further enhance the catalytic activity by modulating the electronic structure. In this study, we synthesized a series of palladium-rare earth (Pd₃RE) alloys supported on carbon to serve as bifunctional catalysts that efficiently promote both ORR and EOR. Compared to Pd/C, the Pd₃Tb/C catalyst exhibits 3.1-fold and 1.8-fold enhancement in activity for ORR and EOR, respectively. The charge transfer in the Pd₃Tb/C results in an electron-rich Pd component, thereby weakening the binding energy with oxygen species and facilitating the two reactions.