Nanocrystalline-glass heterostructure via phase engineering for efficient hydrogen evolution

The development of efficient, stable, and low-cost electrocatalysts is crucial for hydrogen production via water electrolysis. While multi-principal element alloys (MPEAs) show great potential due to their multi-component synergy and tunable electronic structures, their practical application is often hampered by insufficient active sites and poor long-term stability. Herein, we report a phase-engineering-guided dealloying strategy to fabricate a high-performance MPEA catalyst for hydrogen evolution reaction (HER). This approach employs a triple-phase Al₆₀Ni₂₇Fe₅Co₅Mo₃ precursor, wherein chemical dealloying in an alkaline medium transforms the BCC parent phase into an ordered B2 phase, while completely dissolving the less stable FCC and tetragonal phases. This process results in a unique heterogeneous structure of Ni-based oxide nanocrystals enveloped by a Mo-rich metallic glass phase, coating the B2 phase surface. Benefiting from the abundant heterogeneous interfaces and synergistic interactions among multiple phases generated during dealloying, the catalyst exhibits outstanding activity and stability for HER in alkaline media, achieving a low overpotential of 35 ​mV at 10 ​mA ​cm⁻² and exceptional durability for 500 ​h at 100 ​mA ​cm⁻² with negligible activity degradation. This work presents a novel pathway for designing multiphase MPEAs and underscores the significant potential of high-performance electrocatalyst preparation by combining phase engineering with dealloying. © 2025 Chinese Materials Research Society.