Palladium nanoparticles integrated ternary nickel cobalt iron hydroxide as an efficient bifunctional electrocatalyst for direct ethanol fuel cell

Abstract

The rational design and identification of the underlying role of the support materials to promote the electrocatalytic activity of the active catalyst are the main objectives of the current research. Herein, we synthesized different compositions of ternary nickel cobalt iron transition metal hydroxide (TMH) supported palladium (Pd) nanoparticles (Pd/Hy) to improve the ethanol electrooxidation reaction (EOR) and oxygen reduction reaction (ORR) kinetics of Pd NPs. The TMH supports modified the surface electronic structures of Pd through strong metal support interaction, thereby improving the EOR and ORR reaction kinetics. Herein, we explored potential-dependent electrochemical impedance spectroscopy (EIS) to identify the intermediates species formed during the ORR and EOR process and rationalize the reaction mechanism. The potential-dependent EIS reveals that TMH supports eliminating the adsorption of the poisonous carbonaceous species during the EOR. The synthesized bifunctional Pd/Hy catalyst integrated alkaline direct ethanol fuel cell device exhibits a peak power density of 28.1 mW/cm2, which is a higher performance than that of the Pt/C integrated devices. Finally, Pd/Hy catalyst-integrated passive DEFC was tested, and a portable electronic application was demonstrated.