Octahedral nanocrystals of PtNiCoMoCu core/shell high-entropy alloy with lattice strain and low-coordination sites enabling CO pathway of alcohol oxidation reaction.

The development of Pt-based catalysts exhibiting high activity and selectivity towards the direct dehydrogenation pathway in direct alcohol fuel cells (DAFCs) is highly desirable, but remains a significant challenge. Herein, we present octahedron PtNiCoMoCu core/shell high-entropy alloy (PtNiCoMoCu HEA) with PtCu core and PtNiCoMo shell, featuring lattice strain and low-coordination sites, and their enhanced electrocatalytic activity towards methanol oxidation reaction (MOR). The electrochemical analysis reveals that PtNiCoMoCu HEA exhibits the unprecedented mass activity (8.0 A mg) and specific activity (9.5 mA cm) for MOR. As revealed by the aberration-corrected electron microscopy, X-ray absorption spectroscopy (XAS) and in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), PtNiCoMoCu HEA with lattice strain and low-coordination sites exhibits significantly weak CO adsorption and exceptional selectivity towards the dehydrogenation pathway during the MOR test. Furthermore, theoretical calculations reveal that Co, in conjunction with Pt, Ni, Mo, and Cu, synergistically enhances electron-transfer productivity in PtNiCoMoCu HEA, thereby improving oxidation capability. This work will provide a valuable reference for the design and fabrication of Pt-based HEA materials, thereby facilitating the development of advanced catalysts exhibiting exceptional catalytic performance for diverse applications.