Titanium undoped

Polycrystalline oxide materials, both undoped and doped, have been extensively examined for use as photoanodes. Ti02 electrodes have been prepared by thermal oxidation of a Ti plate in an electric furnace in air at 300-800°C (15-60 min) and in a flame at 1300°C (20 min) [27-30]. XRD analysis of thermally oxidized samples indicates the formation of metallic sub-oxide interstitial compounds, i.e. TiOo+x (x < 0.33) or Ti20i y (0 < y < 0.33) and Ti30 together with rutile Ti02 [27]. The characteristic reflection of metallic titanium decreases in intensity after prolonged oxidation (60 min) at 800° C indicating the presence of a fairly thick oxide layer (10-15 pm). Oxidation at 900°C leads to poor adhesion of the oxide film... 

Heterojunctions have recently been fabricated using electrochemically prepared polypyrrole and metal (indium, titanium, aluminium and tin). It has been revealed that carrier concentration, estimated as 1.5 x 10 and 5 x 10 in doped and undoped polypyrrole samples, respectively, plays an important role in controlling the junction... 

Sato, M. Sambito, M. A. Aslani, A. KaUdioran, N. M. Slamovich, E. B. Webster T. J. Increased osteoblast functions on undoped and yttrium-doped nanocrystaUine hydroxyapatite coatings on titanium. Biomateriab, 2006,27,2358-2369. 

Ti02 nanoparhcles, as-doped, could also be used for the disinfection of waste-water. For example, Yu et al. reported that sulfur-doped titanium dioxide exhibited a strong visible-light-induced anhbacterial effect [29], while Egerton et al. found that the photoelectrocatalytic disinfechon of E. coli by an iron-doped Ti02 sol-gel electrode was more efficient than disinfection by the corresponding electrode when undoped [30]. 

Undoped p-type anatase has also been prepared through the sol-gel method, by reacting titanium isopropoxide and HCl in ethanol, and depositing thin films through dip coating. Surprisingly, the authors do not discuss the reason for such behavior, but they present sensing results for ethanol detection that support the p-type nature of the prepared anatase films [89]. 

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