Use of modified anodization procedures to prepare advanced TiO2 nanostructured catalytic electrodes and thin film materials

摘要

The preparation and characteristics of (i) thin films based on an ordered array of TiO2 nanotubes (NT) supported on flexible Ti metallic substrate, (ii) free-standing TiO2 NT thin films and (iii) hedgehog-type TiO2 thin films are investigated. It is evidenced the possibility of a fine tuning of the nano-architecture in relation to applications going from advanced catalytic (photo)electrodes to nanomembranes requiring different nanostructure for an optimized behavior. In the first type of materials, a key issue determining the resistance to electron transfer and performances is the interface between the TiO2 NT layer and the metallic substrate. Some aspects of the preparation in controlling nanomorphology and photocurrent generation properties are discussed. In free-standing TiO2 NT thin films the mechanism of formation of flow-through nanomembranes is analyzed. The possibility of generation of hedgehog-type TiO2 thin films by etching with HF is also shown, evidencing some of the potential advantage of these catalytic materials, particularly for self-cleaning properties. (C) 2014 Elsevier B.V. All rights reserved.