Titanate and Titania Nanotubes: Synthesis, Properties and Applications

ContentsAbbreviations ixList of symbols xiChapter 1 Introduction and Scope 1 1.1 The history of nanomaterials 1 1.1.1 The importance of TiO2 and titanate nanomaterials 3 1.2 Classification of the structure of nanomaterials 5 1.3 Synthesis of important elongated nanomaterials 7 1.3.1 Metal oxide nanotubes 7 1.3.2 Metal chalcogenide nanotubes 12 1.3.3 Mixed oxides, silicates and other compounds as nanotubes 13 1.4 Techniques and instruments used to study nanomaterials 15 References: 16Chapter 2 Synthesis Techniques and the Mechanism of Growth 19 2.1 Template methods 19 2.2 Alkaline hydrothermal synthesis of elongated titanates 23 2.2.1 Alkaline hydrothermal synthesis of titanate nanotubes and nanofibres 24 2.2.2 Mechanism of nanostructure growth 26 2.2.3 Methods to control the morphology of nanostructures 33 2.3 Electrochemical (anodic) oxidation 35 2.3.1 Principles and examples 35 2.3.2 Mechanism of nanotube growth 38 2.3.3 Methods to the control the morphology of nanotubes 40 2.4 Conclusions 42 References 43Chapter 3 Structural and Physical Properties of Elongated TiO2 and Titanate Nanostructures 47 3.1 Crystallography 47 3.1.1 Crystallography of titanate nanotubes 47 3.1.2 Crystallography of titanate nanofibres, nanorods and nanosheets 51 3.1.3 Crystallography of anodized and template assisted TiO2 52 3.1.4 Conclusions 52 3.2 Adsorption, surface area and porosity 53 3.2.1 Surface area of nanotubes 53 3.2.2 Pore volume of nanotubes 56 3.2.3 Effect of ionic charge on adsorption from aqueous solutions 59 3.3 Electronic structure of titanate nanotubes 61 3.3.1 Spectroscopy of titanate nanotubes: UV-Vis, Pl, ESR, XPS, NMR, Raman and FTIR 63 3.3.2 Electrical-, proton- and thermal conductivities of titanate nanotubes 70 3.4 Physical properties of TiO2 nanotube arrays 71 References 73Chapter 4 Chemical Properties, Transformation and Functionalization of Elongated Titanium Oxide Nanostructures 77 4.1 Thermodynamic equilibrium between the nanotube and its environment 77 4.2 Ion-exchange properties of nanostructured titanates 80 4.2.1 Kinetic characteristics of ion-exchange 80 4.2.2 Decoration of nanotubes using using the ion-exchange method 86 4.2.3 Decoration of substrates with nanotubes 88 4.3 Surface chemistry and functionalization of nanostructured titanates 91 4.4 Stability of nanotubes and phase transformations 92 4.4.1 Thermal stability 92 4.4.2 Acidic environments 95 4.4.3 Mechanical treatment 95 References 95Chapter 5 Potential Applications 98 5.1 Energy conversion and storage 98 5.1.1 Solar cells 98 5.1.2 Lithium batteries 101 5.1.3 Fuel cells and batteries 104 5.1.4 Hydrogen storage and sensing 107 5.2 Catalysis, electrocatalysis and photocatalysis 108 5.2.1 Reaction catalysis 108 5.2.2 Supercapacitors and general electrochemistry 115 5.2.3 Photocatalysis in elongated titanates and TiO2 117 5.3 Magnetic materials 124 5.4 Drug delivery and bio-applications 125 5.5 Composites, surface finishing and tribological coatings 126 5.6 Other applications 128 References 128