Synergistic Electrochemical and SPR Fiber Sensor for Mechanistic Insights into Dimethoate Catalytic Degradation

Real-time monitoring of the pesticide degradation process is critical for ensuring biological safety and preventing potential ecological risks. However, current detection methods generally depend on offline sampling and subsequent laboratory analysis. To overcome this limitation, we designed a dual-signal platform that integrates surface plasmon resonance (SPR) and electrochemical catalysis within a compact fiber for in situ monitoring of dimethoate (DMT) degradation. On this platform, electrochemistry was employed both to drive DMT degradation and to record the catalytic behavior, while SPR enabled continuous optical tracking of the dynamic formation and disappearance of intermediate species. Furthermore, WO₃/TiO₂ gradient composites (0%, 10%, 20%) were deposited on the fiber surface, and the degradation kinetics were monitored via the SPR optical signal. The 10 wt % WO₃/TiO₂ sample reached a degradation efficiency of 90.3%, owing to WO₃-induced enhancement of the TiO₂ interfacial electronic structure. This compact fiber sensor, with integrated optical and electrochemical capabilities, offers a robust platform for in situ mechanistic and kinetic studies of catalytic degradation.