Atomic Dispersed Oxophilic Mo‐Tailored Core–Shell PdAu@Pd With Intrinsic Tensile Strain Boost Bifunctional Electrocatalysis

The rational design of high‐performance bifunctional electrocatalysts for oxygen reduction reaction (ORR) and ethanol oxidation reaction (EOR) remains pivotal for advancing direct ethanol fuel cells (DEFCs). Herein, we report Mo‐doped core–shell PdAu@Pd nanocrystals (Mo‐PdAu@Pd) with intrinsic tensile strain as an exceptional bifunctional catalyst. The synergistic integration of Mo dopants and a PdAu@Pd core–shell architecture optimizes electronic configurations via d‐band center downshifting, while oxophilic Mo and lattice strain engineering enhance intermediate adsorption and reaction kinetics. In alkaline media, Mo‐PdAu@Pd delivers a record mass activity of 0.992 A mg Pd −1 at 0.9 V for ORR, surpassing commercial Pt/C and Pd/C by 8.07‐ and 9.92‐fold, respectively, with only 4.7% activity loss after 10,000 cycles. For EOR, it achieves 5.95 A mg Pd −1 , outperforming Pt/C and Pd/C by 5.13‐ and 5.41‐fold, alongside superior durability. In situ Raman spectroscopy and density functional theory (DFT) calculations reveal that the incorporation of oxophilic Mo species acts as auxiliary active sites, promoting O 2 adsorption and * OOH formation, while together with the intrinsic tensile strain, the surface electronic state is optimized, which leads to higher ORR activity of Mo‐PdAu@Pd. This work provides a universal strategy for engineering strain‐modulated, dopant‐enhanced catalysts, offering a guideline for the rational design of exceptional bifunctional catalysts.