Abstract: Platinum-based catalysts, particularly Pt/C, are widely employed in direct methanol fuel cells (DMFCs); however, their practical deployment is hindered by severe drawbacks, including carbon support corrosion and the high cost of Pt, which collectively compromise long-term durability and economic feasibility. To overcome these limitations, we present the design of an ultrathin, urchin-like PdPtCu ternary alloy supported on CeO₂ nanosheets, specifically engineered to enhance both the activity and stability of the methanol oxidation reaction (MOR). A central innovation of this work lies in the employment of a CuO-CeO₂ composite support, which enables efficient incorporation of copper via an acid-mediated ligand exchange process—addressing the inherent challenge of immobilizing metallic species on oxide surfaces. The incorporation of CuO facilitates the oxidative activation of copper species, while CeO₂ contributes structural robustness and redox-active sites that promote intermediate removal during MOR. The resulting PdPtCu-CeO₂ nanostructures exhibit a high surface area and unique urchin-like morphology, both of which contribute to markedly enhanced electrochemical performance. Compared to commercial Pt/C, the PdPtCu-CeO₂ catalyst demonstrates approximately threefold enhancements in both mass and specific activities, along with excellent long-term durability as confirmed by chronoamperometric measurements. This work study highlights the promise of oxide-derived hybrid supports and multi-metallic nanostructures for advancing cost-effective and durable electrocatalysts for DMFC applications, thereby advancing the pursuit of next-generation, carbon-free catalyst platforms.

Key words: Metal oxide supports, PdPtCu alloy on CeO₂ nanosheets, Electrocatalysis, Methanol oxidation reaction, ligand-exchange method