Nanostructured anodic films on transition metals prepared using the electrochemical anodization method have recently attracted particular attention owing to their extraordinary properties and potential use in a variety of applications. Herein, we provide a thorough review of the anodization fabrication of anodic films with different nanostructures, including nanopores, nanotubes, nanoflowers, nanoneedles and nanowires on transition metals, focusing on the growth processes of nanostructured anodic films on three representative transition metals, namely, iron, copper and zinc. Specific consideration is given to the anodization behavior and formed film nanostructures of these transition metals. We conclude that electrolyte composition plays a key role in influencing the final morphologies of anodic films. Fluoride-containing solutions represent universal electrolytes for forming nanostructured anodic films on transition metals. The main applications of the resulting nanostructured anodic films, especially in energy-related fields, such as photoelectrochemical water splitting and supercapacitors, are also presented and discussed. Finally, we indicate the main challenges associated with the fabrication of anodic films with highly ordered nanostructures and the potential future directions of this field are indicated.

Nanostructured Anodic Metal Oxides: Synthesis and Applications reviews the current status of fabrication strategies that have been successfully developed to generate nanoporous, nanotubular and nanofibrous anodic oxides on a range of metals. The most recent achievements and innovative strategies for the synthesis of nanoporous aluminum oxide and nanotubular titanium oxide are discussed. However, a special emphasis is placed on the possibility of fabrication of nanostructured oxide layers with different morphologies on other metals, including aluminum titanium, tantalum, tin, zinc, zirconium and copper. In addition, emerging biomedical applications of synthesized materials are discussed in detail. During the past decade, great progress has been made both in the preparation and characterization of various nanomaterials and their functional applications. The anodization of metals has proven to be reliable for the synthesis of nanoporous, nanotubular and nanofibrous metal oxides to produce a desired diameter, density, aspect ratio (length to diameter) of pores/tubes, and internal pore/tube structure. - Provides an in-depth overview of anodization techniques for a range of metals - Explores the emerging applications of anodic metal oxides - Explains mechanisms of formation valve metal oxides via anodization

This book guides beginners in the areas of thin film preparation, characterization, and device making, while providing insight into these areas for experts. As chemically deposited metal oxides are currently gaining attention in development of devices such as solar cells, supercapacitors, batteries, sensors, etc., the book illustrates how the chemical deposition route is emerging as a relatively inexpensive, simple, and convenient solution for large area deposition. The advancement in the nanostructured materials for the development of devices is fully discussed.

[Truncated abstract] This work studies the formation mechanisms of anodized materials and their related electrochemical anodic behaviors. Electrochemical anodization is a versatile method to create various materials with intricate nanostructured morphologies. These materials have potentials for various functional applications in chemical and biomedical sensing, photocatalysis, energy conversion in batteries and supercapacitors. The study is focused on three main aspects: experimental synthesis of anodized materials, theoretical analysis of formation mechanisms of anodized materials and fabrication metallic nanowires using anodized porous alumina. The following summarizes the highlights of the study. Firstly, different anodized structures are synthesized experimentally, including nano-channeled anodized alumina, nanoporous anodized tin oxide and anodized SnC2O4 particles. The related electrochemical behaviors of the metals during anodization are quantified and explained. Anodization current oscillations: The phenomenon of spontaneous periodical current oscillation during electrochemical anodization of tin in alkaline electrolytes is observed. Such phenomenon has been reported in the literature. Attempts have been made to explain this phenomenon on the basis of oxide film lift-off and electrolyte diffusion. This study demonstrates that the current oscillation is caused by oxygen generation and release on the tin anode, causing periodic redistribution of ion concentration in the electrolyte. The analysis also enables determination of the contributions of the two anodic reactions of tin oxidation and oxygen generation to the total anodic current. Secondly, a unified theory for the formation of surface structures of metals induced by anodization is proposed. The theory is based on thermodynamic and electrochemical principles. It is able to explain the main experimental observations of all three types of anodic structures, including solid compact oxide films, porous oxides and porous metal surface layers...

This dissertation proposed to initiate the research into the fabrication of metal/oxide nanostructures by anodization process for biosensor, drug delivery and supercapacitor applications by producing different nanostructures which lead to the potential for various applications. This study focuses on the establishment of the knowledge and techniques necessary to perform metal/oxide nanostructures on biological and energy applications. This study will investigate: (1) the sensor and drug delivery applications of micro/nano structures; (2) novel processes to innovate anodic aluminum oxide nanotube template; (3) the supercapacitor applications of anodic titanium oxide. First, the extremely high surface area AAO coated microneedle and microneedle array can be developed as sensor and drug delivery devices. Due to the large surface area of the AAO, the film can absorb indicators to make it sensitive to testing targets. pH detection was demonstrated to show the sensing capability of the microneedle. Then, the microneedles were further built as an array by combining micromachining technique. The microneedle array provides a 3-D structure that possesses several hundred times more surface area and capacity than a traditional nanochannel template. Second, the nanoengineering process was conducted to innovate anodic aluminum oxide nanotube template. Guided anodization assisted by nanoimprint process formed AAO arrays that can be formed on controlled locations. More importantly, it shows the periodically ordered AAO array with different sizes of nanopores. With the improved AAO template, melting injection, electro/electroless deposition and sol-gel deposition were conducted to fabricate Ni nanowires/ TiO2 nanotubes, Ni/BaTiO3 core-shell nanotubes, and UHMWPE nanotubes. Third, various Ti-based alloys were anodized to form ordered nanotubes for supercapacitor application. Ti alloy oxide contains some porous layers which are not presented on TiO2 nanotube film. Thus, Ti alloys anodized oxide nanotubes have better supercapacitor behaviors than the conventional TiO2 nanotubes. However, a high surface area nanoporous Ti/TiO2 structure, which was fabricated by selective etching process, can accumulate large quantity of electrons and energy for supercapacitor needs. Additionally, nanoporous metals obtained by dealloying hold a unique combination of a highly conductive network and a bicontinuous open. The characteristics formed through dealloying also present a nice charge/discharge behavior and a good capacitance performance. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152487

This book gives detailed information about the fabrication, properties and applications of nanoporous alumina. Nanoporous anodic alumina prepared by low-cost, simple and scalable electrochemical anodization process due to its unique structure and properties have attracted several thousand publications across many disciplines including nanotechnology, materials science, engineering, optics, electronics and medicine. The book incorporates several themes starting from the understanding fundamental principles of the formation nanopores and theoretical models of the pore growth. The book then focuses on describing soft and hard modification techniques for surface and structural modification of pore structures to tailor specific sensing, transport and optical properties of nano porous alumina required for diverse applications. These broad applications including optical biosensing, electrochemical DNA biosensing, molecular separation, optofluidics and drug delivery are reviewed in separated book chapters. The book appeals to researchers, industry professionals and high-level students.

Nanostructured Anodic Metal Oxides: Synthesis and Applications reviews the current status of fabrication strategies that have been successfully developed to generate nanoporous, nanotubular and nanofibrous anodic oxides on a range of metals. The most recent achievements and innovative strategies for the synthesis of nanoporous aluminum oxide and nanotubular titanium oxide are discussed. However, a special emphasis is placed on the possibility of fabrication of nanostructured oxide layers with different morphologies on other metals, including aluminum titanium, tantalum, tin, zinc, zirconium and copper. In addition, emerging biomedical applications of synthesized materials are discussed in detail. During the past decade, great progress has been made both in the preparation and characterization of various nanomaterials and their functional applications. The anodization of metals has proven to be reliable for the synthesis of nanoporous, nanotubular and nanofibrous metal oxides to produce a desired diameter, density, aspect ratio (length to diameter) of pores/tubes, and internal pore/tube structure. Provides an in-depth overview of anodization techniques for a range of metals Explores the emerging applications of anodic metal oxides Explains mechanisms of formation valve metal oxides via anodization

Anodic Oxidation of Aluminium and Its Alloys focuses on the basic principles of anodic oxidation, choice of materials, pretreatment, design, properties of the anodic film, testing, and maintenance. Organized into 16 chapters, this book begins with the principles of anodizing; applications of anodized aluminum; factors influencing the choice of grade of aluminum for anodizing; and factors influencing the choice of anodizing process. Subsequent chapters explain designing for anodizing; anodizing equipment; jigging (racking) methods for anodizing; chemical treatment processes before anodizing; and the anodizing process. The coloring, sealing, and stripping of the anodic coating; testing anodized aluminum; properties of anodized aluminum; maintenance of anodized aluminum; and effluent treatment for anodizing plants are also described. This text will be useful to students, technicians, product designers, architects, and engineers in the aluminum industry.

As a versatile, straightforward, and cost-effective strategy for the synthesis of self-organized nanomaterials, electrochemical anodization is nowadays frequently used to synthesize anodic metal oxide nanostructures for various solar cell applications. This chapter mainly discusses the synthesis of various anodic TiO2 nanostructures on foils and as membranes or powders, and their potential use as the photoanode materials based on foils, transparent conductive oxide substrates, and flexible substrates in dye-sensitized solar cell applications, acting as dye-loading frames, light-harvesting enhancement assembly, and electron transport medium. Through the control and modulation of the electrical and chemical parameters of electrochemical anodization process, such as applied voltages, currents, bath temperatures, electrolyte composition, or post-treatments, anodic nanostructures with controllable structures and geometries and unique optical, electronic, and photoelectric properties in solar cell applications can be obtained. Compared with other types of nanostructures, there are several major advantages for anodic nanostructures to be used in solar cells. They are (1) optimized solar cell configuration to achieve efficient light utilization; (2) easy fabrication of large size nanostructures to enhance light scattering; (3) precise modulation of the electrochemical processes to realize periodic nanostructured geometry with excellent optical properties; (4) unidirectional electron transport pathways with suppressed charge recombination; and (5) large surface areas by modification of nanostructures. Due to the simple fabrication processes and unique properties, the anodic nanostructures will have a fascinating future to boost the solar cell performances.

This study was performed to determine optimum parameters of anodizing process in order to develop AAO film for various applications in electronic field. This study focussed on the influence of anodizing parameters such as anodizing voltage, electrolyte temperature and electrolyte concentration to the growth of AAO film.