Electrodeposition of silver from the ionic liquid Butylpyridinium dicyanamide

Abstract

The electrodeposition of silver was performed on a platinum electrode from a non-fluorinated ionic liquid (IL), butylpyridinium dicyanamide (Pyri4-DCA). The as-studied IL is characterized by a high ionic conductivity (11.03 mS.cm−1) and a low dynamic viscosity (24.4 mPa.s), which are appropriate for the electrodeposition process. The cyclic voltammetry (CV) curves recorded in Ag-DCA/Pyri4-DCA solutions showed the presence of reduction and oxidation peaks, respectively associated with the deposition and stripping of silver from the Pt surface. The diffusion coefficient of Ag(I) calculated from CV curves varied from 5.3 10−7 to 1.1 10−7 when Ag+ concentration was changed from 1 to 10 mM. The silver was electrodeposited on the Pt surface at different constant potentials. The nuclei size and population density of silver were monitored by varying the electrolyte concentration, the applied potential and the deposition time. From the analysis of the experimental transient curves, it was shown that the electrochemical deposition process of silver follows a 3D nucleation with diffusion-controlled growth. The nuclei population densities and diffusion coefficients were also determined for various chronoamperometric parameters by using the fitting model of Scharifker and Hills for 3D nucleation and growth.