New highly efficient electrochemical synthesis of dispersed Ag2O particles in the vicinity of the cathode with controllable size and shape

Abstract

Silver(I) oxide (Ag₂O) hexapod particles were electrochemically synthesized with high efficiency in an aqueous solution of silver nitrate and sodium sulfate. The generation of dispersed Ag₂O particles in the vicinity of the cathode was explained by a two-step reaction mechanism involving the reduction of water, 2H₂O + 2e⁻ → H₂ + 2OH⁻, followed by the precipitation of Ag₂O particles, 2Ag⁺ + 2OH⁻ → Ag₂O + H₂O. The applied potential played an important role in controlling the size and yield of the Ag₂O hexapods. The average size of the hexapod particles was adjusted from 1.84 down to 0.60 μm by increasing the applied potential from 4 to 10 V. Furthermore, the ratio of the Ag₂O/Ag that was produced was determined to be ca. 23 when the applied potential was increased up to 10 V. On the other hand, the morphological change exhibited by the Ag₂O particles was determined to be a function of the silver ion concentration, which is proportional to the growth rate. The Ag₂O hexapods formed as a consequence of fast growth along the equivalent 〈100〉 directions.