Monitoring of the Transfer of Tetrachloroaurate(III) Ions by Thin-layer Electrochemistry and Electrochemical Deposition of Metallic Gold over a Graphite Electrode

摘要

This study demonstrates the electrochemical conversion of the synthetic procedure of monolayer-protected clusters using a thin toluene layer over an edge plane pyrolytic graphite electrode. A thin toluene layer with a thickness of 0.31 mm was coated over the electrode and an immiscible liquid/liquid water/toluene interface was introduced. The transfer of the tetrachloroaurate (AuCl4?) ions into the toluene layer interposed between the aqueous solution and the electrode surface was electrochemically monitored. The AuCl4? ions initially could not move through into the toluene layer, showing no reduction wave, but, in the presence of the phase transfer reagent, tetraoctylammonium bromide (TOABr), a cathodic wave at 0.23 V vs. Ag/AgCl was observed, indicating the reduction of the transferred AuCl4? ions in the toluene layer. In the presence of dodecanethiol together with TOABr, a self-assembled monolayer was formed over the electro-deposited metallic gold surface. The FE-SEM image of the surface indicates the formation of a highly porous metallic gold surface, rather than individual nanoparticles, over the EPG electrode.