Synthesis of TiO2 Thin Films: Relationship Between Preparation Conditions and Nanostructure

Abstract

The influence of the synthesis conditions (pH, HF concentration, procedure of application of the voltage) during the anodization of Ti foils to produce TiO 2 thin films characterized by an ordered arrays of 1D nanostructures (nanorods, nanotubes) is discussed. Different types of 1D nanostructures could be obtained by changing the procedure of synthesis, as shown by field emission scanning electron microscopy images. The analysis of the current versus time curves during the procedure of synthesis provides indications on the sequence of processes occurring during the synthesis. It is also suggested that different growing mechanisms occur depending on the preparation, leading in turn to the different type of nanostructures observed. The relevance of this preparation method is related to the analysis of the relationship for oxide materials between nano-architecture and reactivity and gives the opportunity to prepare materials with an intermediate degree of complexity between model and applied catalysts.

Electrolyte-less design of PEC cells for solar fuels: Prospects and open issues in the development of cells and related catalytic electrodes

“…We have focused our attention on TiO 2 as semiconductor and a preparation method based on anodic oxidation (AO) of Ti nanopunched foils [109][110][111][112]. This technique is widely used to produce ordered arrays of titania nanotubes [113,114], including for photocatalytic uses [115], but has been very limited utilized to prepare porous photoanodes for PEC solar cells, except for DSSC cells which have different requirements (produce electrical energy rather than convert solar-to-chemical energy).…”

Photo-Electrochemical Sensing of Dopamine by a Novel Porous TiO2 Array-Modified Screen-Printed Ti Electrode

“…This visible light absorption could be due to a structural resonance effect typical of 2D-type photonic materials [ 28 ]. This effect can be seen with titanium oxide, especially for nanoporous structures, due to the positive interaction between the wavelength of irradiated light and the periodicity of the crystal structure, thus providing a wide absorption in the 500–780 nm range, as previously observed [ 29 ]. However, the modified TiO 2 -nanoporous SPE did not take advantage of this light absorption property as it generated a photocurrent when irradiated by a LED at 400 nm, as will be shown in Section 3.2 .…”

Towards Solar Fuels from Water and CO2

“…[70] A good method is the anodic oxidation of titanium thin foils to form ordered arrays of vertically-aligned titania nanotubes. [72] The same device can be used also for the production of physically separated flows of H 2 and O 2 during water photoelectrolysis ( Figure 3). This device could also be used to produce renewable H 2 by photocatalytic reforming of chemicals present in waste streams from agro-food or agro-chemical production (such as diluted streams of ethanol, glycerol, etc.)…”