An Ultrafast and Stable High-Entropy Metallic Glass Electrode for Alkaline Hydrogen Evolution Reaction

A new type of high-entropy alloy with a composition of Pt₂₅Pd₂₅Ni₂₅P₂₅(at.%) and an amorphous structure, referred to as a high-entropy metallic glass (HEMG), was developed by a scalable metallurgical technique for efficient hydrogen evolution reaction (HER). The achieved overpotential was as low as 19.8 mV at a current density of 10 mA cm^-2while maintaining an ultrareliable performance for 60 h in 1.0 M KOH solution, exhibiting 5- and 10-times higher performance than those of traditional Pt₆₀Ni₁₅P₂₅and Pd₄₀Ni₄₀P₂₀metallic glasses, respectively, and also surpassing the benchmark performance of commercial Pt/C nanoparticles and pure Pt sheet. Experimental and theoretical results revealed that the enhanced HER activity was ascribed to a synergistic function of multiprincipal components that optimized the electronic structure to accelerate the rate-determining steps in HER. Moreover, the unique long-range disordered structure provided a high density of unsaturated atomic coordination that was able to improve the amount of electrochemically active sites. This bulk HEMG strategy paves the way for the development of flexible freestanding electrodes for water splitting applications.