Dual-function MBene catalyst: Fe2B2 MBene as iron source and electron donor in self-sustaining Fenton oxidation

Phthalates are a class of widely used endocrine-disrupting chemicals, presenting substantial health hazards upon their release into aquatic environments. Herein, the catalytic potential of two-dimensional transition metal borides (MBenes, including Fe 2 B 2 , MnB, MoB, and Mo 1.33 B) as co-catalysts for activating diverse peroxides in Fenton/Fenton-like oxidation processes, with particular emphasis on optimizing the Fe(III)/Fe(II) cycling efficiency. Under optimized conditions, the Fe 2 B 2 /hydrogen peroxide (H 2 O 2 ) system demonstrated superior catalytic performance, achieving complete degradation of dimethyl phthalate (DMP) within 15 min. This system exhibited pseudo-first-order rate constants that were 5.7–154.3 times higher than those of other MBenes/Fe(III)/H 2 O 2 systems, highlighting its exceptional catalytic efficiency. Notably, Fe 2 B 2 exhibited exceptional stability through five consecutive cycles, maintaining DMP degradation rates (∼100 %) with minimal boron leaching (∼1.05 mg/L). Mechanistic studies revealed a dual activation pathway. Surface-bound Fe(II) species decompose H 2 O 2 directly to produce hydroxyl radicals. Meanwhile, B–Fe–B bridges facilitate Fe(II) regeneration by transferring electrons from iron atoms or B B bonds in Fe 2 B 2 to dissolved FeOH 2+ species. This synergistic interaction establishes a self-sustaining catalytic cycle that significantly enhances the Fenton reaction kinetics. These findings establish Fe 2 B 2 MBene as dual-functional material that serves as both a sustainable dual-function catalyst and an efficient iron source, providing new perspectives for designing MBene-based catalysts for environmental remediation applications.