Electrochemical Synthesis of Silver Icosahedrons for SERS Sensing Applications

Ag icosahedrons, characterized by the size-dependent distribution of strain fields, has garnered increasing interests across disciplines from crystallography to materials science. However, the metastability arising from such intrinsic strain greatly restricts the available synthetic routes. Here, we present a facile aqueous-phase electrodeposition technique for the robust synthesis of Ag icosahedrons. By decreasing the Ag reduction rate, we achieve enhanced control over the electrodeposition kinetics, as quantitatively evidenced by the apparent activation energy. The pronounced kinetic stability allows for the synthesis of particles up to 5 µm in size within 10 min (Pretreatment time: 48 h). Through systematic variation of applied potentials, currents, and electrolyte compositions, we enable the design of Ag icosahedrons with tunable hierarchical structures. These structured particles can be effectively employed as surface-enhanced Raman spectroscopy (SERS) substrates for pesticide detection. This work establishes a stable and pure model system that facilitates the straightforward synthesis of metastable structures.