Mesoporous PtPd Alloy ‐ High Entropy Oxide Heterostructures for Efficient Electrocatalytic Methanol Oxidation Reaction

and long-term operational stability are achieved in a DMFC assembled with mesoporous PtPd-HEO, surpassing the performance of cells based on Pt/C and PtPd/C. In situ spectroscopic studies combined with density functional theory (DFT) simulations reveal that the valence electronic structure of the PtPd alloy is modulated by the HEO component, resulting in improved selectivity for non-CO pathways and increased formation of reactive hydroxyl species. Superior MOR catalytic activity and durability for PtPd-HEO are attributed to this synergistic electronic tuning and the porous structure. The development of HEO-based mesoporous heterostructures is proposed as a promising strategy for the design of next-generation catalysts in energy conversion and sustainable technologies.