Thermite‐Synthesized Fe–Ti–Al–Mg High‐Entropy Intermetallic Compound for Efficient Azo Dye Degradation

Most high‐entropy alloys (HEAs) tailored for contaminant degradation suffer from complex fabrication processes and high‐cost alloy design. Furthermore, low‐cost active elements such as Fe and Mg cannot be readily alloyed into HEAs via conventional routes. Herein, the catalytic performance and multicomponent synergistic mechanism of a low‐cost Fe–Ti–Al–Mg high‐entropy intermetallic compound synthesized via aluminothermic reduction were systematically investigated for azo dye degradation. The high‐entropy intermetallic compound possesses a single‐phase, lattice‐distorted structure, in which immiscible Fe and Mg are successfully incorporated, offering a unique structural foundation for synergistic catalysis. The degradation process displays a two‐stage kinetic behavior, consisting of a rapid initial stage followed by a stable degradation stage. Under optimized conditions, over 80% of the dye is removed within only 30 s, and the degradation efficiency reaches nearly 95% within 10 min. Furthermore, the catalyst retains more than 80% of its degradation efficiency over 10 consecutive cycles, exhibiting high cycling stability. Such superior stability can be attributed to the preferential dissolution of Mg, which accelerates dye cleavage and promotes the sustained release of Fe 2+ via vacancy formation, thereby continuously driving Fenton‐like reactions and enabling deep degradation of the dye. These results demonstrate that this low‐cost Fe‐ and Mg‐containing high‐entropy intermetallic compound represents a promising candidate material platform for wastewater treatment.