Tailored Interatomic Interactions in High-Entropy Alloys for Enhanced Electrocatalytic Hydrogen Evolution Reaction in Alkaline Water

Interatomic interactions play a crucial role in electrocatalysts for the efficient hydrogen evolution reaction (HER). However, understanding the effect of interatomic interactions in high-entropy alloys (HEAs) on HER is challenging due to their complex compositions. In this study, we meticulously designed a series of quinary and senary HEAs (PtPd- and PtPdRu-HEA) with tailored interatomic interactions. Notably, a specific hydrogen spillover pathway facilitated by atomic interactions in PtPd-HEA was unveiled. By means of the hydrogen spillover effect (HSE), a decent alkaline HER performance was achieved with PtPd-HEA, exhibiting an overpotential of only 12 mV at 10 mA cm^-2, and a stability exceeding 200 h in 1 M KOH. Moreover, using PtPd-HEA as a cathode and NiFe-LDH as an anode, the as-fabricated anion exchange membrane water electrolyzer exhibited a high operational stability exceeding 100 h at 1 A cm^-2. And, the detrimental role of Ru to weaken the desorption of *H on PtPdRu-HEA via decreasing the lattice distortion rate of the (111) plane was identified. Consequently, PtPdRu-HEA exhibited HER activity lower than that of PtPd-HEA.