ChemInform Abstract: Protection of Photoanodes Against Photocorrosion by Surface Deposition of Oxide Films. Criteria for Choosing the Protective Coating.

ChemInform Abstract

Criteria for choosing protective oxide deposits for photoanodes are defined on the basis of the most likely and efficient mechanisms of charge transport. One of two strategies adopted consists of protecting the photoanode by surface deposition of a non-conducting oxide film while a second possibility is the protection of the photoanode by a conducting oxide film in which the carrier transport occurs, close to the Fermi level, via a partially filled band or a sufficiently high density of localized states. The validity of the first model is confirmed by the significant photocurrents observed with the n-GaAs/Sr_0.98Na_0.01Ce_0.01TiO₃ hybride electrode structure. The second method is illustrated by using a deposit of n-SrTiO₃ on n-GaAs. The PEC n-GaAs/n-SrTiO₃|0.1 M IO₃^-, 0.1 M I^-, 0.1 M KOH|Pt shows conversion yields as high as 18% for an irradiation of 5 mW/cm².