Carbon-supported bimetallic Pd-Ir catalysts for alkaline sulfide oxidation in direct alkaline sulfide fuel cell

Abstract

In this paper, carbon-supported palladium (Pd) and its alloys with iridium (Ir) were investigated for the purpose of alkaline sulfide oxidation and ultimately for application as anodes in direct alkaline sulfide fuel cell (DASFC). Physical and electrochemical characterizations, such as X-ray diffraction, transmission electron microscopy, energy dispersive X-ray, cyclic voltammetry, linear sweep voltammetry, I-V analysis, and electrochemical impedance spectroscopy were carried out. Pd9Ir1/C exhibited the highest activity, showing the lowest onset potential and the highest current density, mass activity, and specific activity. The maximum power density of a DASFC single cell with a Pd9Ir1/C anode was 33.98 mW cm(-2) at 70 A degrees C, which was 35 % higher than that obtained with Pd/C. It is thought that the incorporation of more oxophilic Ir into Pd promoted the adsorption of OHads at a lower potential, and Pd9Ir1/C led to optimal OHads coverage, which played a catalytic role and thus resulted in the best performance.