Water-flow-induced rapid directional electron transfer via Mo-S-Fe bridge bonds for enhanced Fe(III)/Fe(II) redox cycling in Fenton-like system

In Fenton-like processes, achieving rapid and efficient redox cycling of metal active centers remains a challenge. This study presents an innovative strategy that harnesses the mechanical energy of water flow to drive the redox cycling of metal active centers. Herein, Fe 3 O 4 /MoS 2 heterojunction with interfacial Mo-S-Fe bridge bonds was constructed via a one-step hydrothermal method. Under the stimulation induced by water-flow mechanical, the piezoelectric effect of MoS 2 generates charge carriers, which are rapidly directed to Fe active sites through the Mo-S-Fe bonds. This process significantly accelerates the Fe(III)/Fe(II) cycle and enhances H 2 O 2 activation, achieving 93.8% removal of sulfamethoxazole (SMX) within 60 min under water flow stimulation. The composite exhibits robust performance across a broad pH range (3.0-10.7) and in the presence of humic acid (HA) and coexisting anions, demonstrating its strong environmental adaptability. Spectroscopic evidence confirmed the formation of Mo-S-Fe bonds at the heterojunction interface. Mechanistic studies further revealed that the structure improves charge separation, promotes rapid electron transfer from MoS 2 to Fe sites, and strengthens H 2 O 2 adsorption, thereby synergistically boosting reactive oxygen species (ROSs) generation and the overall catalytic efficiency. This study proposes an innovative strategy that exploits mechanical forces generated by water flow to drive rapid redox cycling of active metal centers in Fenton-like reactions.