Carbon supported bimetallic Pd–Co catalysts for alkaline sulfide oxidation in direct alkaline sulfide fuel cell

In this study, carbon supported Pd and Pd–Co alloys were synthesized and investigated as anode catalysts for the practical application of a promising sulfide-fed fuel cell, named direct alkaline sulfide fuel cell (DASFC). Physical and electrochemical properties of the Pd/C and Pd–Co/C catalysts were evaluated using X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray (EDX), inductively coupled plasma optical emission spectroscopy (ICP-OES), cyclic voltammetry (CV), linear sweep voltammetry (LSV), I–V analysis and electrochemical impedance spectroscopy (EIS). Among all the Pd-based catalysts tested, Pd 8 Co 2 /C showed the highest sulfide oxidation activity in terms of the lowest onset potential and the highest current density, mass activity, and specific activity at −0.2 V (vs. Ag/AgCl). The maximum power density of DASFC with Pd 8 Co 2 /C anode catalyst was 46.82 mW cm −2 at 70 °C, which is 26% higher than that with Pd/C. It is speculated that the incorporation of Co into Pd facilitated the adsorption of OH ads at a lower potential, and Pd 8 Co 2 /C provided the optimal coverage of OH ads that played a catalytic role and thus led to the highest performance.