Search

Survey of cyclic voltammograms of lower aliphatic alcohols in 1 M KOH recorded at electrodes containing atomic gold is presented. The atomically structured gold is placed in polyaniline, which is deposited on a platinum electrode. The electrochemical behavior of these atomic gold electrodes (AGE) is compared with Pt/polyaniline electrode without gold and with Pt/polyaniline electrode containing “unstructured” nanoclusters of Au. The conditions were identical for all of the experiments. This allows direct visual comparison of the effect of atomic structuring. The electrochemical activity of the AGEs is dominated by the odd–even pattern of reactivity, and it is superimposed on specific electrochemical behavior of individual alcohols.

The previously described cyclic pathway method for deposition of atomic metals has been used to create Pd1–6 atomic clusters and Au1–5Pd1 and Au1–4Pd2 bimetallic atomic clusters in polyaniline (PANI). The controlled deposition of predetermined atomic size clusters of metals has been examined by testing the electrochemical oxidation of n-propanol in 1 M NaOH. The oxidation peak currents from the cyclic voltammograms were found to follow the same trend as the changes of the calculated HOMO–LUMO gap energies. The FTIR signature of PANI for these films also followed the calculated trend. This study also looks at the effects of atomic arrangement in the atomic structure on the support matrix of PANI. The results presented here have shown that the cyclic pathway is a versatile method for the atomic deposition of single metal, bimetallic, or even trimetallic atomic clusters in PANI.

Under precisely controlled conditions, atomic gold electrodes with even or odd number of Au atoms per polyaniline repeat unit (Pt/PANI/Au N for 0

Polyaniline (PANI) has been an effective matrix for hosting and preserving metal nanoclusters. In the case of gold, the tetrachloroaurate anion (AuCl ― 4 ) has a high affinity for the imine sites of PANI. Upon contact with PANI, AuCl ― 4 is spontaneously reduced to metallic gold, but the size of the formed Au clusters cannot be precisely controlled. Herein, we report on the electrochemical method of controlled deposition of one atom by one atom of gold per imine site of PANI. By controlling the potential, we keep PANI in an oxidized state while exposing it to a solution of AuCl ― 4 to form a PANI * AuCl ― 4 complex, which is reduced to atomic gold by sweeping the potential negative. This 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.