Tubular and fibrous nanostructures of titanates have recently been synthesized and characterized. Three general approaches (template assisted, anodic oxidation, and alkaline hydrothermal) for the preparation of nanostructured titanate and TiO2 are reviewed. The crystal structures, morphologies, and mechanism of formation of nanostructured titanates produced by the alkaline hydrothermal method are critically discussed. The physicochemical properties of nanostructured titanates are highlighted and the links between properties and applications are emphasized. Examples of early applications of nanostructured titanates in catalysis, photocatalysis, electrocatalysis, lithium batteries, hydrogen storage, and solar‐cell technologies are reviewed. The stability of titanate nanotubes at elevated temperatures and in acid media is considered.

An illustrated review of reticulated vitreous carbon (RVC) as an electrode material is presented. Early uses of RVC were largely restricted to small-scale (< 1 cm 3 ) electroanalytical studies in research laboratories. RVC properties of a high ratio of surface area to volume and minimal reactivity over a wide range of process conditions, combined with low cost and easy handling, have resulted in a steady diversification of its applications both in research laboratories and in industry. The physical structure of RVC (in terms of pores per linear inch, strut length, strut thickness and area of the trigonal strut) is examined for 10, 30, 60 and 100 ppi (pores per linear inch) grades using scanning electron microscopy. The accurate measurement of these geometrical values presents both theoretical (in terms of definition of trigonal strut area, beginning and end of single strand) and practical problems (large differences in strut length and thickness in individual samples). Data are presented to show the relationships between geometrical properties. Applications include electroanalytical studies and sensors, metal ion removal, synthesis of organics and FentonÕs reagent, H 2 O 2 production and batteries/fuel cells.

The sorption of hydrogen between the layers of the multilayered wall of nanotubular TiO2 was studied in the temperature range of -195 to 200 degrees C and at pressures of 0 to 6 bar. Hydrogen can intercalate between layers in the walls of TiO2 nanotubes forming host-guest compounds TiO2 x xH2, where x < or = 1.5 and decreases at higher temperatures. The rate of hydrogen incorporation increases with temperature and the characteristic time for hydrogen sorption in TiO2 nanotubes is several hours at 100 degrees C. The rate of intercalate formation is limited by the diffusion of molecular hydrogen inside the multilayered walls of the TiO2 nanotube. 1H NMR-MAS and XRD data confirm the incorporation of hydrogen between the layers in the walls of TiO2 nanotubes. The nature and possible applications of the observed intercalates are considered.

The long-term stability of titanate nanotubes, which were produced by alkaline hydrothermal treatment of TiO 2 , was studied at room temperature in acidic, pure water, and basic aqueous suspensions. In pure water and basic (0.1 mol dm -3 NaOH) solutions, the nanotubes were stable and minimal morphological changes occurred. In 0.1 mol dm -3 H 2 SO 4 , suspended titanate nanotubes slowly transformed to rutile nanoparticles of ca. 3 nm size, which were agglomerated into ellipsoidal particles. The porosity, crystal structure, and morphology of protonated titanates and TiO 2 have been studied for intermediate states during the transformation by nitrogen adsorption, XRD, Raman spectroscopy, SEM, and HRTEM. The rate of conversion of nanotubes to nanoparticles has been related to the concentration of soluble titanium-(IV) in solution, which depends on the nature of the acid. Thermodynamic and kinetic aspects of the acid transformation are discussed.