An investigation of the sulphur(−II)/sulphur(0) system on bold electrodes

Abstract

Sulphur deposited on gold by the anodic oxidation of sulphur(−II) species in solution has been studied by X-ray photoelectron spectroscopy. The initial layer behaved as gold sulphide. Multilayers of sulphur had a lower volatility and a smaller electron binding energy than bulk elemental sulphur, indicating that there is interaction with the underlying gold or gold sulphide. The anodic oxidation of sulphur(−II) to sulphur, and the reverse process, has been investigated on gold using the rotating ring disc electrode technique. Polysulphide ions were formed as intermediates in both processes. Polysulphides were also produced by chemical reaction of deposited sulphur with sulphur(−II) species in solution. The polysulphide intermediates were identified as S 2− 5 at pH 13, a mixture of species with average stoichiometry S 2− 3.3 at pH 9.2 and S 2− 2, possibly HS − 2, at pH 6.8.