Synthesis and Performance Study of Pd/CeO₂ Composite Catalyst for Enhanced MOR Activity

The present study investigates the interplay between structural composition and electrochemical characteristics of carbon-supported palladium-cerium oxide (Pd-CeO₂) composites. The catalysts were synthesized using the polyol method and their potential for methanol oxidation reaction (MOR) was examined. The characterization of the prepared composites are performed using X-ray diffraction and transmission electron microscopy. The results confirm the crystal structure and that there was uniform dispersion of Pd nanoparticles on the carbon support. The methanol oxidation activity was strongly affected by cerium in the Pd catalyst which is observed by cyclic voltammetry. The most active PCC3 composite (Pd/C with 30 wt.% CeO₂) with significantly low Pd content showed remarkably higher activities than the commercial Pt/C catalyst. The Pd nanoparticles occupied the surface of CeO₂, thus enhancing the Pd/CeO₂ interface. The higher concentration of oxygen vacancies at the CeO₂ surface developed strong interactions at Pd/CeO₂ interface which improved the MOR effectively. The maximum current density of 1740 mA cm⁻² at the voltage of 0.27 V was obtained with PCC3 (30 wt.%). These results showed that the CeO₂ based Pd/C catalyst is an attractive candidate for anode material in a direct methanol fuel cell.