PHOTOELECTROCHEMICAL PROPERTIES OF BISMUTH OXYHALIDE FILMS

The photoelectrochemical (PEC) properties of bismuth oxyhalide (BiOCl, BiOBr, and BiOI) electrodes prepared by anodic oxidation of bismuth films on a platinum substrate have been studied. In acidified potassium halide solutions, these electrodes have been found to exhibit the PEC properties characteristic of p-type semiconductors. The efficiency of the PEC process appreciably decreases in the series BiOCl > BiOBr > BiOI. Effective protectors of the BiOHal electrode photodecomposition are dissolved oxygen and hydroquinone/quinone redox pair. The spectral sensitization of BiOHal electrodes can be carried out by different dyes, the quantum efficiency of the sensitized process being relatively high (3-7%) in a number of cases. The ways of increasing the stability of sensitized PEC process on BiOHal electrodes are considered. © 1990.