Rapid fabrication of silver microplates under an oxidative etching environment consisting of O2/Cl−, NH4OH/H2O2, and H2O2

Abstract

Morphologically controlled micro-/nanostructures have gained considerable interest as they offer unique properties associated with size, shape, and crystallographic facets. In this paper, we report a simple yet rapid protocol for large scale synthesis of silver microplates (AgMPls) from a silver ammine complex ([Ag(NH₃)₂]⁺) under an etching environment containing O₂/Cl⁻, NH₄OH/H₂O₂, and H₂O₂ capable of dissolving silver crystals except plate structures. H₂O₂ is employed as the sole reducing agent. Chloride ions are essential for creating an etching environment capable of selective dissolution of singly and multiply twinned crystals, while leaving plate structures unaffected. Without chloride ions, H₂O₂ reduces the [Ag(NH₃)₂]⁺ complex to silver microparticles containing truncated cubes, icosahedra, pentagonal rods, and plate microstructures with icosahedra as the major product. The developed protocol enables environmentally friendly fabrication of highly pure AgMPls and AgMPs directly from the AgCl precipitate.