TiO(2) is one of the most studied compounds in materials science. Owing to some outstanding properties it is used for instance in photocatalysis, dye-sensitized solar cells, and biomedical devices. In 1999, first reports showed the feasibility to grow highly ordered arrays of TiO(2) nanotubes by a simple but optimized electrochemical anodization of a titanium metal sheet. This finding stimulated intense research activities that focused on growth, modification, properties, and applications of these one-dimensional nanostructures. This review attempts to cover all these aspects, including underlying principles and key functional features of TiO(2), in a comprehensive way and also indicates potential future directions of the field.

TiO2 nanotubes: synthesis and applications.

The present paper gives an overview and review on self-organized TiO2 nanotube layers and other transition metal oxide tubular structures grown by controlled anodic oxidation of a metal substrate We describe mechanistic aspects of the tube growth and discuss the electrochemical conditions that need to be fulfilled in order to synthesize these layers Key properties of these highly ordered, high aspect ratio tubular layers are discussed In the past few years, a wide range of functional applications of the layers have been explored ranging from photocatalysis, solar energy conversion, electrochromic effects over using the material as a template or catalyst support to applications in the biomedical field A comprehensive view on state of the art is provided

TiO2 nanotubes: Self-organized electrochemical formation, properties and applications

In the present review we try to give a comprehensive and most up to date view to the field, with an emphasis on the currently most investigated anodic TiO2 nanotube arrays. We will first give an overview of different synthesis approaches to produce TiO2 nanotubes and TiO2 nanotube arrays, and then deal with physical and chemical properties of TiO2 nanotubes and techniques to modify them. Finally, we will provide an overview of the most explored and prospective applications of nanotubular TiO2.

One-dimensional titanium dioxide nanomaterials: nanotubes.

Self-ordering electrochemistry: a review on growth and functionality of TiO2nanotubes and other self-aligned MOx structures

Titanium Dioxide Nanomaterials for Sensor Applications

In this paper we address several key aspects to the formation mechanism of self-organized oxide nanotube layers grown by anodization of valve metals and their alloys in fluoride ion containing electrolytes. We suggest that (i) the self-organized structure is produced as a result of an autocatalytic reaction, in which electrochemical oxidation and chemical dissolution of oxide accelerate each other; (ii) in the initial growth stage the competition for oxidizable area between neighboring initial growth spots is a key element in self-organization; and (iii) the diameter of the nanotubes on different materials and as a function of anodization voltage is strongly related with the anodic growth factor (nm/V) of the valve metal oxides. Additionally, for multilayer pore structure growth the present work provides insight into the sites of highest reactivity in repeated anodization experiments (bottom of the pores, in between pores).

Mechanistic Aspects of the Self-Organization Process for Oxide Nanotube Formation on Valve Metals

Control of morphology and composition of self-organized zirconium titanate nanotubes formed in (NH4)2SO4/NH4F electrolytes

Electrochemical formation of self-organized zirconium titanate nanotube multilayers

Abstract Silicon solar cells are crucial devices for generating renewable energy to promote the energy and environmental fields. Presently, high-purity silicon, which is employed in solar cells, is manufactured commercially via the Siemens process. This process is based on hydrogen reduction and/or the thermal decomposition of trichlorosilane gas. The electrochemical process of producing silicon has attracted enormous attention as an alternative to the existing Siemens process. Thus, this article reviews different scientific investigations of the electrochemical production of silicon by classifying them based on the employed principles (electrorefining, electrowinning, and solid-state reduction) and electrolytes (molten oxides, fluorides, chlorides, fluorides–chlorides, ionic liquids [ILs], and organic solvents). The features of the electrolytic production of silicon in each electrolyte, as well as the prospects, are discussed.

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Kouji Yasuda

Papers

TiO2 nanotubes: Self-organized electrochemical formation, properties and applications

Mechanistic Aspects of the Self-Organization Process for Oxide Nanotube Formation on Valve Metals

Control of morphology and composition of self-organized zirconium titanate nanotubes formed in (NH4)2SO4/NH4F electrolytes

Electrochemical formation of self-organized zirconium titanate nanotube multilayers

Electrochemical production of silicon