Noble metal free high entropy alloys with amorphous based heterostructures for the oxygen evolution reaction

Abstract

Designing cost-effective catalysts with high activity and stability for the oxygen evolution reaction (OER) is important to scale-up the water electrolysis process for hydrogen production. Herein, (FeNiCuCoZn)_90−xV_xP₁₀ (x = 10, 15, and 20, denoted as V₁₀, V₁₅, and V₂₀) high entropy alloys (HEAs) with well-integrated amorphous phase and Fe₂P crystalline phase heterostructures were successfully synthesized by a facile ball milling method. The designed composite exhibits very small charge transfer resistance and high active area, enabling rapid charge/mass transport and sufficient access to catalytic sites. Consequently, it only requires an ultra-low overpotential of 228 mV at a current density of 10 mA cm⁻² and a small Tafel slope of 23.6 mV dec⁻¹ in an alkaline environment, outperforming other amorphous contrast samples and commercial RuO₂. The excellent activity and high durability make the reconstructed V₂₀-HEA a promising candidate for catalyzing the OER process. This work brings fresh insights into heterogeneous interface engineering for advanced electrocatalyst designing.