Indium Tin-Doped Oxide (ITO) as a High Activity Water Oxidation Photoanode

Photochemical water oxidation was carried out at a mesoporous nanoparticle film composed of indium tin-doped oxide (nanoITO). Annealing nanoITO at temperatures above 250 degrees C affects both conducting and semiconducting properties. Impressive photoelectrochemical activity was observed at this degenerate n-type semiconductor electrode, outperforming the traditional semiconductor titanium dioxide (TiO2) under the same conditions. In a 0.1 M HNO3 solution, the nanoITO electrode sustained photocurrents of 1.0 mA/cm(2) at an Eapplied = 1.5 V vs saturated calomel electrode (SCE) (eta = 0.55 V) under a 90 mW/cm(2) UV illumination (375 nm). This activity is compared to similar to 0.3 mA/cm(2) with a traditional TiO2 electrode under the same potential and conditions. Evidence for oxygen generation in the photolysis experiments was quantified using the collector-generator method, and >70% photocurrent efficiency for O-2 production was confirmed at this nanoITO photoanode.