Insight into reactive oxygen species pathway regulation: Boosting FeS₂ Fenton catalysis via wet mechanochemically...

Boron modification has been validated as an efficient strategy for boosting Fe-based Fenton catalysis. Nevertheless, it remains challenging to synchronously achieve boron doping and heterostructure modulation while steering ROS generation pathways. Herein, a novel B-FeS₂ nanocatalyst with dual modification was synthesized via a wet mechanochemical-thermal method. Boron modification constructs a FeS₂/boron sheet heterostructure that suppresses oxidation and agglomeration, while introducing electron-donating BB and FeB bonds. The B-FeS₂ Fenton system achieves >90% BPA removal across a wide pH range (3-10), exhibits K_obs and mineralization efficiency 1.4 and 1.89 times higher than those of bare FeS₂, respectively, and maintains stable performance over five cycles and 12 h continuous operation. Mechanistic studies reveal that B doping upshifts the Fe d-band center, which correlates with an altered H₂O₂ cleavage pathway characterized by enhanced ·O₂^- generation alongside sustained ·OH production, suggesting a possible shift in the relative contribution of homolytic versus heterolytic pathways. The generated ·O₂^- directly degrades BPA and sustains Fe²⁺/Fe³⁺ cycling via the Haber-Weiss reaction, a synergy particularly advantageous under alkaline or anoxic conditions. This work demonstrates that B modification serves as an effective electronic modulator for FeS₂, providing mechanistic insights into designing iron-based Fenton system with tailored ROS pathways.