Stretchable high-entropy alloy nanoflowers enable enhanced alkaline hydrogen evolution catalysis

High-entropy alloys have received much attention in many fields for their unique physicochemical properties, yet precise control at the atomic level in terms of size and morphology remains a great challenge. Herein, we report a kind of stretchable Pt(Co/Ni)MoPdRh HEAs nanoflowers (NFs) assembled by ultra-thin nanosheets (∼ 1.68 nm) for alkaline hydrogen evolution reaction (HER) via one-step wet chemical strategy. The mass activity of HEA NFs reaches 16.64 A mgHEA−1, which is 6.38 times higher than that of commercial Pt/C. The enhanced HER performance and stability is attributed to the multiple active sites in HEAs for reducing the water dissociation energies barriers as well as favoring H adsorption and the strain effect induced by unique structure. This work not only provides a general method for synthesizing unique structures of high entropy alloys, but also provides a fundamental understanding for the study of catalysis in HEAs. [Display omitted] •Pt(Co/Ni)MoPdRh Nanoflowers assembled by ultra-thin nanosheets (~ 1.68 nm) are first reported in high entropy catalysis.•PtCoMoPdRh Nanoflowers exhibits enhanced hydrogen evolution reaction (HER) activity and stability in alkaline electrolyte.•The multiple active sites and strain effect regulate the water dissociation energies barriers and Gibbs free energy of H.•The role of constitute metals in PtCoMoPdRh HEA is elucidated by XPS results and theoretical calculations.