Physical and Electrochemical Effect of Bimetallic Pd–Mo Nanoalloys Supported on Vulcan XC-72R Carbon as Cathode Catalysts for Proton Exchange Membrane Fuel Cell

Synthesis of the bimetallic carbon-supported Pd and PdMo electrocatalysts via the chemical reduction with sodium borohydride as a reducing agent is presented. The Pd/C and PdMo/C electrocatalysts were used as cathode electrocatalysts in proton exchange membrane (PEM) fuel cells in order to examine their catalytic activity. The characterization of the prepared nanoparticles has been carried out using various methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy- dispersive X-ray analysis (EDX). Moreover, the activities of the produced catalysts have been determined using cyclic voltammetry (CV), chronoamperometry, electrochemical impedance spectroscopy (EIS), and single-cell PEM fuel cell. The findings reveal that the crystallite size of the electrocatalysts Pd and Pd–Mo is less than 5.5 nm and that the Pd–Mo/C catalyst exhibits high activity for the oxygen reduction process when used alone. Furthermore, catalysts outperform other temperatures at 70 °C under varied cell temperatures and Mo concentrations in a single-cell fuel cell. A single cell using Pd–Mo/C as the cathode achieves a maximum power density of 107 mW cm⁻² at its maximum current density. Maximum current densities of synthesized catalysts at 70 °C cell temperature were measured as 61, 116, 188, and 168 mA cm⁻² for Pd/C, PdMo/C, PdMo₂/C, and PdMo₃/C catalysts, respectively. The efficiency according to the current of the PdMo₂/C cathode catalyst at 70 °C was 52%, and Pd/C, PdMo/C, and PdMo₃/C cathode catalysts at the same temperature were calculated as 26%, 38%, and 50%, respectively. The evenly scattered nanoparticles and more crystalline lattice flaws in the Pd–Mo/C catalyst are thought to be responsible for the catalyst’s superior performance.