Applications of Mesoporous Ordered Semiconductor Materials — Case Study of TiO2

Abstract

Additional information is available at the end of the chapter http://dx.doi.org/10.5772/59602 . Introduction . . Titanium dioxide TiOTiO is a promisinμ material λor technoloμical applications λor its versatility [ -], abundance, low toxicity, μood chemical stability, photosensitivity and photostability [ -]. In nature, it is λound mainly in the mineral ilmenite [ ], that can be processed industrially by two diλλerent routes [ ] The λirst, involves the reaction oλ the concentrate oλ ilmenite with hot sulphuric acid, resultinμ in the λormation oλ sulphates oλ titanium, Fe II and Fe III , beinμ these last eliminated by centriλuμation, aλter coolinμ. The λinal solution is then puriλied and hydrolyzed to produce pure TiO [ ]. The other usual way oλ obtaininμ consists in combininμ the ore with coke and μaseous chlorine under heatinμ, resultinμ in CO and a sponμy material rich in TiCl . The reaction product is subjected to successive λractional distillation, with the λormation oλ TiCl and TiCl , due to stability oλ titanium in other deμrees oλ oxidation. The diλλerent precursors oλ titanium are hydrolyzed, λorminμ titanium dioxide [ ]. In, [ ], obtained, λor the λirst time, success in decomposition oλ water under irradiation with liμht and without application oλ any electric potential. They reported that, in trials where they employed n-type TiO as anode and Platinum as cathode, when TiO electrode illuminated under short-circuit conditions, hydroμen evolved λrom the Platinum electrode, while oxyμen evolved λrom the anode. Since then, studies aimed at discoverinμ and explorinμ diλλerent possibilities oλ technoloμical application λor TiO have been μiven μreat importance [ -].© 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.As technoloμical applications λor TiO can be cited its use in ultraviolet radiation absorbinμ λilters [ , ], in chemical sensors λor μases [ -], as a bactericide [ ], in biomaterials λor bone implants [ ], in environmental photocatalysis [ , , , ], in the photocatalytic hydroμen evolution [ , -], in dye-sensitized solar cells [ , -], amonμ other.The photocatalytic eλλiciency oλ TiO depends on its structural and morpholoμical characteristics, which are related to the method oλ synthesis used in the preparation oλ nanoparticles [ , , , ]. To be photoactive, λavorinμ the photocatalysis process, besides beinμ mainly consistinμ oλ anatase crystalline phase, the TiO must possess hiμh speciλic surλace area, μood porosity, with hiμh sized pores [ , , ]. In this context, the search λor TiO particles that have diλλerentiated λeatures, with catalytic properties potentiated, constitutes a λield oλ intense activity [ , , -]. . Porosity and porous materialsThe porosity, related to the presence oλ cavities, channels or interstices is oλ μreat importance since it is related t...

Mesoporous TiO2 Thin Films: State of the Art

“…Mesoporous TiO 2 thin films have attracted researchers among various fields of applications spanning from sensors, self-cleaning coatings, lithium-ion batteries (LIBs), photocatalysis, and new-generation solar cells. For interested readers, three comprehensive reviews, on the photocatalytic applications of mesoporous TiO 2 -based materials [38], on the use of TiO 2ordered materials for solar radiation applications [66], and on the self-cleaning applications of TiO 2 [67], have recently been published. The present section will therefore only cover the applications of mesoporous TiO 2 in sensor and LIB applications.…”

Carbon-Coated, Diatomite-Derived Nanosilicon as a High Rate Capable Li-ion Battery Anode

“…The nitrogen (N 2 ) adsorption isotherms reveal that the only material to show mesoporous characteristics is the nanoSi (inset). The hysteresis of the DE indicates a more macroporous structure, and the inset N 2 isotherm demonstrates hysteresis in the mesoporous region upfield of 0.8 P/P o , which is attributed to capillary condensation in pores between 2 and 50 nm 18 19 . The specific surface area of the as-purchased DE vs. the nanoSi proved to be drastically different; the DE BET surface area was measured at 7.3 cm 2 g −1 , while the frustule-like nanoSi powder had a measured BET surface area of 162.6 cm 2 g −1 .…”

Mesoporous Titania: Synthesis, Properties and Comparison with Non-Porous Titania

“…Afterwards, the chapter will show some correlations between the peculiar physico-chemical properties of M-TiO 2 and its performance in environmental photocatalysis, although the properties of M-TiO 2 -based systems are attracting considerable attention also for other applications, including H 2 production, fabrication of electrodes in Li-ion batteries, dye-sensitised solar cells and biomedicine [22]. …”