Multilayer catalysts with glass-crystal dual-phase heterostructures for exceptional alkaline water electrolysis under industrial conditions

FeNi-based materials are potential catalysts for industrial alkaline water electrolysis, with the performance dependent on their phase characteristics. Particularly, FeNi-based catalysts with supra-nano crystalline-amorphous dual phases are promising due to high surface energy and abundant active sites. However, scalable production of such durable, highly active amorphous catalysts remains a challenge. Here we utilize a mild corrosion strategy in a weakly acidic salt solution to scalably synthesize glass-crystal dual-phase FeNi-based catalysts from Fe₄₀Ni₄₀P₁₄B₆ amorphous ribbons by inducing surface nanocrystallization. The selective dissolution of specific components in weak acid triggers atomic rearrangement, resulting in a supra-nano phase heterostructure, while prolonged etching simultaneously promotes the development of a multilayer architecture. The Fe₄₀Ni₄₀P₁₄B₆-based OER electrode achieves 2500 mA cm⁻² at 2.2 V in alkaline water electrolysis (AWE) under industrial conditions (80°C, 30 % KOH). With lower cost compared against the precious-metal catalyst, this electrolyzer exhibits about 2.5 times performance (1000 mA·cm⁻²) larger than that of RuO₂ (400 mA·cm⁻²) at 1.8 V, while maintaining this performance for over 300 h. DFT calculations reveal that the multilayer amorphous–crystalline interface enhances charge transfer to the catalytic surface and lowers the activation barrier for *O to *OOH conversion at adsorption sites. The low-cost and high efficiency of the experimental approach, coupled with the high performance of supra-nano Fe₄₀Ni₄₀P₁₄B₆ materials, suggest prospects for its potential industrial application. © 2025 Elsevier Ltd