A SERS characterization of the stability of polythionates at the gold–electrolyte interface

Anode current on gold in mixed thiosulfate-sulfite electrolytes

“…The polysulfide layer on gold can be formed not only by electrochemical oxidation of thiosulfate but also by its long-lasting exposure to these solutions. According to SERS studies of the gold-electrolyte interface under thiosulfate-based leaching conditions [26][27][28], the products of thiosulfate decomposition are monoatomic and polymeric sulfur. These products of thiosulfate decomposition are formed after A C C E P T E D M A N U S C R I P T long-lasting (more than 60 min) metal-solution contact.…”

RDE study of thiosulfate oxidation on gold

“…The mechanism of this transformation has not been studied in detail, but the results of SERS measurements taken at a gold nanorod array electrode in [12,13] confirm that the possible participants of this process-tetrathionate, trithionate, sulfite, and thiosulfatedecompose to cyclo-S 8 , polymeric sulfur, and monoatomic sulfur at the gold surface. It should be stressed that in the case of indifferent electrode (for example, glassy carbon electrode) the formed tetrathionate gets oxidized to sulfate without the formation of elemental sulfur [7].…”

“…Considering the mechanisms of electrode reactions (4) and (5) one cannot but notice that the stage of charge transfer is the same for these two reactions, namely reaction (7) for thiosulfate oxidation and reaction (12) for gold oxidation (dissolution). In both cases charge transfer occurs between the metal and adsorbed monoligand compound of gold and thiosulfate.…”

The effect of tetrathionate on the anodic process of gold thiosulfate leaching

“…18 From the above findings, it can be said that the polythionates may not be observed on a gold surface during the passive process, but they do exist in the leaching solution in the form of decomposition products of thiosulfate. 17 To the best of our knowledge, the effect of tetrathionates on the topography changes of the gold surface, and the formation of the passive layer during the process of gold dissolution in the absence of copper, has not been studied satisfactorily. 15,20 In our previous reports, 21 the addition of tetrathionates increase gold dissolution over a prolonged leaching time because of the weak passivation.…”