Ag/AgCl has been deemed as a suitable reference electrode for photoelectrochemical water splitting studies under AM 1.5 G and UV light irradiation. A number of previous studies have reported its use in PEC studies. I have been using Ag/AgCl (in 3M KCl) for water splitting studies under neutral and mildly alkaline conditions (pH 7-8), and notice a slight but well defined color change to a brown color upon prolonged AM 1.5 G illumination. This is pretty interesting, and I would like to hear if any of you had noticed this (or is it some mistake on my experimental plan!!)
Considering the fact that AgCl itself is photoactive and is known to photodecompose upon visible and UV radiation, could this be a case of photodecomposition? Moreover, Ag/AgCl and AgCl by itself has also been used as photocatalyst for dye degradation. Considering these aspects, can we now begin doubting the reliability of the Ag/AgCl reference for PEC water splitting studies??