Trace substance detection and in situ photocatalytic degradation using recyclable ag nanoparticle/ Ag3PO4 tetrapod composite on SERS fiber probes

With the increasing discharge of pollutants into air, water, and soil, the rapid and sensitive detection and treatment of chemical pollutants, including toxic organic dyes and heavy metal ions, have become critical for minimizing potential threats to the ecological cycle and human health. In the current research, an in-situ degradation approach for toxic substances is proposed, combined with surface-enhanced Raman scattering (SERS). Fiber probes based on a silver nanoparticles/ silver phosphate tetrapod (Ag/ Ag 3 PO 4 ) composite were fabricated using a sequence of ion exchange, chemical reduction, and subsequent coating processes. The fiber probes were deployed for ultra-sensitive SERS detection and in situ photocatalytic degradation of dyes (specifically crystal violet (CV)) and heavy metal ions (particularly Hg 2+ ). The probes were functionalized with 4-mercaptopyridine (4-MPY) to facilitate the detection of Hg 2+ . Notably, the probes demonstrated detection limits as low as 10 −14  M for crystal violet (CV) and 4-aminothiophenol (PATP), and 10 −12  M of Hg 2+ . Under light exposure, the substrate degraded 93.2 % of CV and 98.0 % of PATP within 60 min, and 82.3 % of Hg 2+ within 30 min, as monitored in situs. Finite element method analysis suggested that the high electromagnetic field intensity generated by Ag/ Ag 3 PO 4 resulted from the close packing of Ag nanoparticles. Furthermore, the SERS fiber probes exhibited outstanding stability, selectivity, and reusability. This research suggest that the recyclable Ag/ Ag 3 PO 4 fiber probes hold significant potential for the detection and in situ monitoring of the degradation of trace environmental contaminants.