Plasmonic Silver Nanostructures for Complementary Catalytic Degradation and Surface‐Enhanced Infrared Absorption Sensing of Organic Pollutants

Plasmonic platforms that combine chemical remediation with on‐site molecular sensing are highly desirable for monitoring and removing organic microcontaminants in water. Here, we report a one‐pot aqueous synthesis of silver nanospheres and nanoprisms stabilized by poly(vinylpyrrolidone) (PVP), poly(vinyl alcohol) (PVA), or ascorbic acid (AA), using H ₂ O ₂ as a shape‐directing agent. UV–vis spectroscopy and transmission electron microscopy (TEM) indicate size and shape control. The resulting silver nanoparticles (AgNPs) were evaluated as catalysts for the reduction of 4‐nitrophenol (4‐NP) and, in the case of PVP‐coated spherical AgNPs, as surface‐enhanced infrared absorption (SEIRA)‐active substrates for the detection of imazalil. In the catalytic reduction of 4‐NP, spherical AgNPs–PVA exhibit the best performance ( k  = 0.156 ± 0.002 min ⁻¹ ), outperforming the other stabilizers at comparable loadings. Our results show that the stabilizer nature and particle morphology influence the catalytic activity. Additionally, spherical AgNPs–PVP act as SEIRA‐active substrates for imazalil, yielding band‐specific enhancement factors of up to 26.7 in the 700–1800 cm ⁻¹ region. Thus, these results indicate the feasibility of using AgNPs obtained through the same synthetic strategy for complementary environmental applications, combining catalytic remediation and spectroscopic detection.