A review on highly ordered, vertically oriented TiO2 nanotube arrays: Fabrication, material properties, and solar energy applications

Nanoporous anodic aluminium oxide has been widely used for the development of various functional nanostructures. So far these self-organized pore structures could only be prepared within narrow processing conditions. Here we report a new oxalic-acid-based anodization process for long-range ordered alumina membranes. This process is a new generation of the so-called "hard anodization" approach that has been widely used in industry for high-speed fabrication of mechanically robust, very thick (>100 microm) and low-porosity alumina films since the 1960s. This hard anodization approach establishes a new self-ordering regime with interpore distances, (D(int))=200-300 nm, which have not been achieved by mild anodization processes so far. It offers substantial advantages over conventional anodization processes in terms of processing time, allowing 2,500-3,500% faster oxide growth with improved ordering of the nanopores. Perfectly ordered alumina membranes with high aspect ratios (>1,000) of uniform nanopores with periodically modulated diameters have been realized.

/pdf/fast-fabrication-of-long-range-ordered-porous-alumina-1bigpxis0y.pdf

Fast fabrication of long-range ordered porous alumina membranes by hard anodization

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

Porous anodic aluminum oxide: anodization and templated synthesis of functional nanostructures.

Siliceous ordered mesoporous materials are well-investigated and -covered by several excellent reviews. Less work has been directed to non-siliceous materials, although these could have more wide-ranging applications. This review will address the synthesis and properties of non-siliceous ordered mesoporous materials, covering oxidic, non-oxidic, metallic, and pure carbon frameworks. Organometallic frameworks, which are typically not synthesized in the presence of surfactants, are beyond the scope of this paper.

J. W. Diggle

Papers

Anodic oxide films on aluminum

The dissolution of porous oxide films on aluminium

A Study of the Formation and Dissolution of Porous Anodic Oxide Films on Aluminum: Behavior of the Porous Layer

Processes Involved in Reattainment of Steady‐State Conditions for the Anodizing of Aluminum Following Formation Voltage Changes

Effect of anodic oxide films on the polarization characteristics of Al