Evaluation of the Stoichiometry between PtCl₆²⁻ and TOA⁺ Ions during the Liquid/Liquid Extraction

Abstract

The transfer of PtCl62− ions into the organic phase facilitated by TOA+ is the very first step in the Brust‐Schiffrin (BS) two‐phase synthesis of monolayer protected Pt nanoparticles. However, the stoichiometry between TOA+ and PtCl62− during the facilitated transfer process is still unknown. In this paper, a hemispherical micro‐liquid/liquid interface, which is formed between a PtCl62− aqueous filled micropipette and an organic phase, has been employed to study the stoichiometry of TOA+ facilitated transfer of PtCl62−. Due to the even diffusion field at the hemispherical micro‐liquid/liquid interface, the theoretical i‐V curve for TOA+ facilitated transfer of PtCl62− can be derived in a simple way. By simulating the theoretical i‐V curve to the experimental voltammogram, the stoichiometry of TOA+ facilitated transfer of PtCl62− was evaluated to be 8.