Ordered mesoporous rutile and anatase TiO2 samples are prepared using mesoporous silica SBA‐15 as template and freshly synthesized titanium nitrate and titanium chloride solutions as precursors. The rutile material formed from the nitrate solution is monocrystalline and contains minimal amounts of Si with a Si:Ti ratio of 0.031(4), whereas the anatase material formed from the chloride solution comprises nanocrystals and contains a higher content of Si with a Si:Ti ratio of 0.18(3). It is found that control of temperature and selection of Ti‐containing precursor play important roles in determining the crystal phase and crystallinity. A possible formation mechanism of porous crystalline TiO2 is suggested. Characterization of these porous materials is performed by XRD, HRTEM, and nitrogen adsorption/desorption. SBA‐15‐templated mesoporous rutile TiO2 exhibits a higher Li ion insertion capability than KIT‐6‐templated TiO2 due to its larger surface area. Likewise mesoporous anatase TiO2:SiO2 composite has a better photoactivity than bulk TiO2 or TiO2‐loaded SBA‐15 for bleaching methylene blue.

Mesoporous monocrystalline rutile TiO 2 has been fabricated at low temperature using mesoporous silicas SBA-15 and KIT-6 as hard templates. The key step of the synthetic process was introducing titanium nitrate complex into the template pores and allowing it to dry, dehydrate, decompose, and finally, form TiO 2 crystals in the pores. It was found that the reaction temperature and concentration of HNO 3 in the used precursor had great effects to the crystallization of TiO 2 . Removal of the silica templates after the TiO 2 crystallization has been investigated. Crystallization of TiO 2 in cage-containing mesoporous silicas, FDU-12 and SBA-16 was not successful, further confirming the previous speculation about strong interaction between the crystals and the wall of silica cages. The porous titanium oxide specimens were characterized by using various techniques, including XRD, HRTEM, and nitrogen adsorption/desorption. Proton conductivity and Li-ion insertion property of the samples were also examined. The highest conductivity, 8 × 10 -3 S cm -1 , was obtained at 50 °C under 100% RH and 1 Li + could be accommodated per TiO 2 unit (335 mA h/g) for the first discharge.

This paper reports a systematic study of the co-doping of SnO2 with Sb and Ni in order to identify the mechanism responsible for the electrocatalytic generation of ozone on Ni/Sb-SnO2. Based on interpretation of a combination of X-ray diffraction, BET surface area measurements (N2) and thermal analysis, the formation of ozone appears to take place on particle surfaces of composite Sb-SnO2 grains, and is controlled by diffusion of OH along internal crystallite surfaces within the grain. Sb-doped SnO2 is inactive with respect to ozone evolution in the absence of Ni, demonstrating a synergic interaction between nickel and antimony. From XPS investigations, Sb(V) ions substitute for Sn(IV) in the lattice, with a preference for centrosymmetric coordination sites whilst the Sb(III) ions occur at grain surfaces or boundaries. Ni was not detected by XPS being located in the subsurface region at concentrations below the detection limit of the instrument. In addition to identifying a possible mechanism for ozone formation, the study resulted in the production of active nanopowders which will allow the fabrication of high surface-area anodes with the potential to exceed the space-time yields of -PbO2 anodes, permitting the application the Ni/Sb-SnO2 anodes in the treatment of real waters.

Nanoparticulate SnO2 produced by a hydrothermal method was characterised by BET, XRD, TGA-MS and in situ variable temperature diffuse reflectance infra red spectroscopy (DRIFTS) to determine the surface behaviour of water. For the (100) facets, hydrogen bonding does not occur, and water adsorption is less strong than for the (111) and (110) facets where hydrogen bonding does occur. Reversible uptake of oxygen was observed. These findings have implications for other surface-gas reactions in which Ni and Sb co-doped SnO2 (NATO) anodes are used for ozone generation. BET showed the relatively high surface area and nanometer scale of the SnO2 particles, whilst XRD confirmed the nano dimension of the crystallites and showed only the cassiterite phase. TGA analysis indicated four temperature regions over which mass loss was observed. These and the in situ DRIFTS studies revealed the existence of various forms of water associated with specific crystal facets of the SnO2, as well as the existence of isolated O-H groups and adsorbed oxygen species. Electronic absorptions were also observed and the data rationalised in terms of the existence of both free electron absorptions, and absorptions from oxygen vacancy states. The role of adsorbed molecular oxygen in electrochemical ozone generation at Ni and Sb co-doped SnO2 (NATO) anodes was strongly suggested by this work.