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We used entropy engineering to design a series of CoFe2O4-type spinels. Through microstructural characterization, electrochemical measurements, and X-ray photoelectron spectroscopy, we demonstrated that the entropy-stabilized oxide (Co0.2Mn0.2Ni0.2Fe0.2Zn0.2)­Fe2O4 has a single-phase spinel structure and exhibits both efficient and stable catalytic oxygen evolution. This is attributable to disordered occupation of multivalent cations, which induces severe lattice distortion and increases configurational entropy, thereby facilitating formation of structurally stable, high-density oxygen vacancies on the exposed surface of the spinel. Thus, more catalytic sites on the surface are activated and retained over the course of long-duration testing for oxygen evolution. Entropy engineering expands researchers’ access to catalysts that link entropy-stabilized structures to useful properties.

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Electrochemical splitting of water to hydrogen is widely considered as an efficient and sustainable solution to relieve the energy crisis. In this work, we report a facile dealloying method based on metallic glass (Ni61Zr36Mo3) to introduce abundant oxygen vacancies (Ov) for the electrocatalytic hydrogen evolution reaction (HER). The corroded ribbons are composed of a sandwich-like structure with Ni–Mo–O nanoporous layer outside and raw metallic glass inside. This complex structure delivers a low overpotential of 71 ± 2.6 mV at −20 mA cm–2 geo in 1.0 M KOH solution, a Tafel slope of 57 ± 3 mV dec–1, and 100 h long-term stability for HER, which is much better than those of the crystallized counterpart, nanoporous Ni, and the commercial benchmark 20% Pt/C electrocatalyst. The high concentration of oxygen vacancies (71.5%), the alloying effect of Mo, and amorphous composition synergistically contribute to the superior electrocatalytic ability and enhanced reaction kinetic of nanoporous Ni–Mo–O, indicating it an excellent low-cost alternative for platinum in hydrogen production.