An investigation of electrochemical contact processes for silver-wire|glassy carbon and silver-coated cotton textile|glassy carbon

Abstract

The electrochemical contact between a glassy carbon substrate and a silver wire or a silver-coated cotton fabric (mechanically fastened to the electrode) is investigated in aqueous phosphate buffer media (with and without sulfide). In contrast to a conventional silver electrode immersed in solution, the “contact” between a silver wire and glassy carbon suffers “anodic disconnection”. Voltammetry, impedance, and chronoamperometry experiments are performed to explore the effect of applied potential on the mechanism of “disconnection/reconnection” processes for the electrochemical contact. A (solubility product dependent) nucleation process with transfer of silver from the coated metal to the glassy carbon is proposed for the “reconnection” mechanism. Furthermore, the effects of (i) HS⁻ in the buffer environment and (ii) H₂S vapour exposure followed by voltammetry, IR, and Raman spectroscopy are investigated in terms of potential for sulfide detection/monitoring applications.