PNNL

Abstract

Plyaniline (PANI) has been shown to be an effective matrix for hosting metal nanoclusters. In the case of gold, the tetrachloroaurate anion (AuCl4) has a high affinity for the imine sites of polyaniline. Upon contract with PANI, AuCl4 is spontaneously reduced to metallic gold, but the size of the formed Au clusters can not be precisely controlled. Herein, we report on electrochemical method of controlled deposition of one atom by one atom of gold per one imine site of PANI. By controlling the potential, we keep PANI in an oxidized state while exposing it to a solution of AuCl4 to form a PANI*AuCl4 complex. The AuCl4 is reduced to atomic gold by sweeping the potential negative. That frees up the imine sites of PANI again and makes them accessible for the next Au deposition cycle. The repeated deposition of Au atoms follows a cyclic pathway. The amount of gold deposited using this method is consistent for each repeated cycle.