Electrochemical codeposition of silver-gold nanoparticles on CNT-based electrode and their performance in electrocatalysis of dopamine

The formation of silver-gold (Ag-Au) bimetallic nanoparticles by electrochemical reduction from a single bath solution is investigated when changing the deposition conditions and parameters (pulse time, deposition duration or concentration ratio). Remarkable differences in the formation of Ag-Au nanoparticles on the carbon substrate are reflected in their morphological and redox features as well as in their composition. The initial stages of deposition were investigated by cyclic voltammetry, followed by optimization of deposition through double-pulse chronoamperometry combined with SEM and EDX studies. The Ag-Au modified electrode is fairly sensitive and responds to dopamine with an oxidation peak at -0.12 V. The electrochemical experiments showed that for 2:1 precursors ratio of AgNO3/HAuCl4 used in deposition, the obtained Ag-Au bimetallic nanoparticles possess the highest electrocatalytic response toward dopamine, within 1-173 mu M range under the optimized conditions (limit of detection 52 nM).