Synergistic redox of dual-shaped silver nanostructures for highly selective sensing of hydrogen peroxide

A novel growth-based plasmonic sensor for hydrogen peroxide (H2O2) determination was developed from dualshaped silver nanostructures consisting of starch-stabilized yellow silver nanospheres (AgNSs) and citrate-capped red silver nanoprisms (AgNPrs). AgNPrs were enlarged through a unique mechanism of AgNSs dissolution to silver ions which are subsequently reduced to silver metal by H2O2. Citrate-capping maintains the lateral anisotropic growth by protecting the AgNPrs from oxidation while exposing the sensitive edges to Ostwald ripening. This highly unique process addresses the selectivity issues encountered with decomposition-based AgNSs/NPrs sensors. Absorbance values from the AgNSs decomposition and AgNPrs growth facilitated a more sensitive spectrophotometric assay through ratiometric analysis. Increasing the concentration of the AgNSs/NPrs sensor to 80:40 ppm also improved sensitivity of naked eye detection of H2O2 by generating a wide range of color transitions. Furthermore, selectivity, accuracy and precision evaluation suggest that the dual-shaped silver nanostructure sensor is a potential alternative to H2O2 determination by allowing a simple, rapid, highly selective, and sensitive measurement.