Charge transfer reductive doping of nanostructured TiO2 thin films as a way to improve their photoelectrocatalytic performance

Nanostructured TiO2 films can be reversibly doped by applying a potential of −0.6 VAg/AgCl in aqueous 0.1 M HClO4 for several minutes. This charge transfer reductive doping causes significant changes of the cyclic voltammograms in the dark. Furthermore, an up to 6-fold increase of the efficiency for water photooxidation is observed upon electrochemical reductive doping. Both observations are explained by the build-up of a space charge layer through agglomerates of appropriately sized and shaped nanoparticles.