Fabrication Process of Ag/AgCl Reference Pseudo-Electrode Based on Electrodeposition of Au on Pt Surfaces from Formaldehyde Baths: Chemical Stability and Adherence

Abstract

Adherence, homogeneity and chemical stability are key fabrication process parameters for Ag/AgCl reference pseudo-electrode. In this work, we were able to achieve reference electrodes over platinum, using an intermediated layer of gold to promote adhesion. The gold bath was prepared using sulfide and formaldehyde. The concentration of formaldehyde was adjusted to prevent electroless deposition during the electrodeposition. The obtained gold deposit was yellow, flat, 200 nm thick with good adherence and resistivity(6.02 μohms cm). Silver and silver chloride layers were deposited with a home-made galvanostatic equipment. The current density was ranged from 0.4 to 8.0 mA cm-2. Finally, a Nafion® 117 membrane was used to recover the AgCl film to avoid corrosion and to maximize lifetime of the reference electrode.

Obtenção de ligas AuxSny utilizando deposição eletroquímica: influência dos aditivos, análise de morfologia e crescimento de multicamadas.

“…Além disso, estão presentes outros elementos no espectro medido. O cloro (Cl) identificado pode ser proveniente do sal de Au (KAuCl 4 ), por incorporação direta [189]. O carbono (C) identificado pode ser proveniente de contaminações do detector do microscópio.…”