Rutile TiO2 thin film electrodes with excellent blocking function and optical transparency

Novel facile synthetic procedure is developed to prepare thin (tens of nm) films of TiO2 (rutile) from thin titanium layers on different substrates. The 'electrochemical' Tauc plot provides more coherent values of the band-gap than the corresponding optical (UV-Vis) spectra. The conduction-band minimum and valence band maximum of our rutile layers are downshifted by ca. 0.2 eV as compared to those of macroscopic single-crystal rutile electrode. The photocurrent onset potentials of water or methanol oxidation are close to the flatband potential, as it is expected from the classical Gartner-Butler model. The blocking quality is monitored by the model redox probes and optimized through the layer thickness and the heat-treatment protocol in the film fabrication. (C) 2019 Elsevier Ltd. All rights reserved.