The influence of rutile particles on photo-induced activity of the sol-gel TiO2/ITO photo-anode

摘要

The rutile effect on structural and photo-electrochemical properties and photo-induced activity were studied. Thin TiO2 layers were prepared by the sol-gel method using a reverse micelles system as a molecular template and deposited on the conductive ITO substrate by a dip-coating technique. Pure anatase or mixed anatase/rutile phase were obtained during the calcination step as a result of the selected temperature. The crystallographic structure was determined by Raman spectroscopy and XRD analysis. The positive influence of the presence of rutile particles in the thin layer on the photo-induced properties was verified. It was found that the mixed crystallographic phase of anatase and rutile can exhibit much higher photo-induced activity than pure anatase or the pure rutile form. The reason for this is that the excited electrons can easily transfer from the anatase surface states to rutile as well as from the anatase conduction band to rutile, which improves the electron-transfer rate. The electron transport between connected anatase and rutile particles can support the photo-excited charge separation and thus reduce the recombination rate.