Waste to Catalyst: Tuning Structure and Composition of Ferrous Scrap‐Derived Alloys by Rapid Solidification for Advanced Catalysis

A significant amount of ferrous scrap resources remain unrecycled, and the abundant iron content gives them potential as environmental catalysts. However, the practical application of ferrous scrap in catalysis remains a significant challenge. Herein, a strategy based on rapid solidification to increase the specific surface area, regulate the microstructure, and introduce high residual stress in ferrous scrap is proposed, leading to enhanced catalytic performance. The introduction of high residual stress and the construction of an amorphous structure significantly enhance performance, enabling a degradation efficiency of 98% within 40 s and a high k_obs of 5.866 min^-1. Theoretical calculations reveal that progressively optimizing the phase structure-from the α-phase to the ε-phase and then an amorphous phase-promotes persulfate (PS) adsorption, and significantly enhances the electron transfer capability. Furthermore, optimizing the composition of the catalyst improves its stability to 30 cycles and develops a novel catalyst with dual functionality for both pollutant degradation and water electrolysis, exhibiting an oxygen evolution reaction (OER) overpotential η₁₀ of 309 mV. These findings provide a new perspective for the recycling of ferrous scrap and offer innovative ideas for developing multifunctional catalytic materials, which are capable of addressing integrated challenges in water treatment and clean energy conversion.