Growth of electrodeposited gold on glassy carbon from a thiosulphate–sulphite electrolyte

Abstract

A solution containing thiosulphate and sulphite has been developed specially for microelectronics applications to replace the conventional cyanide-based bath for long-term sustainability of gold electroplating. However, at the end of the electrodeposition process, the spent electrolyte can contain a significant amount of gold in solution. Investigations have been done to study the feasibility of gold recovery from the spent thiosulphate-sulphite electrolyte. In a previous work, flat plate glassy carbon was used to study the initial nucleation mechanism of gold deposition. However, in that study the growth of nuclei or their eventual formation into a gold film was not examined. Here, we present the microscopy observations of crystal growth of gold on glassy carbon at longer deposition times as a function of deposition potentials. It was found that the initial deposition of gold at low-cathodic potential corresponds to an electrochemical diffusion controlled gold discharge from which spherical nuclei are obtained. After a certain time the initial growing nuclei become unstable and the thin gold deposit begins to develop tips, which eventually grow larger and produce dendrites. The dendritic growth is controlled by surface-diffusion limitations of gold.

l-Arginine-assisted electrochemical fabrication of hierarchical gold dendrites with improved electrocatalytic activity

“…To date, many researches were conducted for the fabrication of Au dendritic nanostructures [26][27][28][29]. For instance, O'Mullane et al synthesized Au dendritic structures by controlling the electrodeposition potential and the introduction of Pb(CH 3 COO) 2 [27].…”

Theoretical and experimental studies of the influence of gold ions and DMH on cyanide-free gold electrodeposition

“…[13][14][15] Nowadays, the main complexing agents studied and used for cyanide-free gold plating electrolytes are sulte and thiosulfate. [16][17][18] Unfortunately, these cyanide-free gold plating electrolytes still suffer from problems of instability, which limits their further study and application. 19 A possible alternate to cyanide is DMH, a low cost and commercially available derivative of hydantoin with good solubility and stability in aqueous solutions in a large temperature range.…”

A Practical Approach in Glycerol Oxidation for the Development of A Glycerol Fuel Cell

“…nucleation phenomenon in which the gold ions are traveling through the electrolyte in a diffusion control behaviour [36]. After the electrode was prepared, two cyclic voltammograms were measured one with glycerol in acidic media (Figure 10c) and one with glycerol in alkaline media (Figure 10d).…”