Titanium oxide electrodes

In nonbiological applications, mixed ruthenium complexes of bipyridyl ligands and substituted pteridine diones have been used as components of photovoltaic cells <2002JPH167>. When fabricated into sol-gel processed titanium oxide electrodes, these complexes achieved photocurrent conversion efficiency in the range 20 8%. 

Barbe C. J., Arendse F., Comte P., Jirousek M., Lenzmann F. and Shklover V. (1997), Nanocrystalline titanium oxide electrodes for photovoltaic applications , J. Am. Ceramic Soc. 80, 3157-3171. 

Loo investigated Raman scattering of electrogenerated iodine on a titanium oxide electrode. He reports signals at 181, 190, and 360 (weak overtone) cm" Also the anti-Stokes transition is seen. The signals were not seen at 488- or 514.5-nm excitation, but only for excitations between 530.9 and 647.1 nm. This strongly indicates resonance scattering. However, that of free iodine is at 515 nm, and the band gap of the oxide is 3 eV (415 nm). Thus one must conclude that the interaction of the iodine with the solid shifts the resonance to lower frequencies. 

Figure 6.32 represents expression (6.51) for an n-type semiconductor electrode in dimensionless form on a logarithmic scale. The calculated curve can be compared to the experimental data shown in Figure 6.33. They were obtained with the Fe(CN)g /Fe(CN)5 system on titanium oxide electrodes (an n-type semiconductor) having different concentrations of charge carriers. The measured anodic and cathodic current density-potential curves resemble those theoretically predicted. In general, charge transfer reactions at semiconducting oxide films do not exactly follow the simple theory outlined above, because other, more complex phenomena can also play a role.

Baez, V.B. Graves, J.E. Pletcher, D. (1992) The reduction of oxygen on titanium oxide electrodes. /. Elec-troanal. Chenu, 340(1-2), 273-86. 

C. Barbe, F. Arendse, P. Comte, et al., Nanocrystalline titanium oxide electrodes for photovoltaic applications, Journal of the American Ceramic Society, vol. 80, no. 12, 3157 pages, 1997. 

The titanium oxide film consists of mtile or anatase (31) and is typically 250-A thick. It is insoluble, repairable, and nonporous in many chemical media and provides excellent corrosion resistance. The oxide is fully stable in aqueous environments over a range of pH, from highly oxidizing to mildly reducing. However, when this oxide film is broken, the corrosion rate is very rapid. Usually the presence of a small amount of water is sufficient to repair the damaged oxide film. In a seawater solution, this film is maintained in the passive region from ca 0.2 to 10 V versus the saturated calomel electrode (32,33). 

These batteries are new systems which use a lithium-manganese composite oxide for the active material of the positive electrode a lithium-titanium oxide with a spinel... 

Lithium-titanium-oxide spinels provide a relatively low voltage of 1.5V vs. lithium. They are, therefore, of interest as possible negative electrode materials for lithium-ion cells [161-163] they can be coupled, for example, to Li[Mn2104 (4V vs. Li) to yield a 2.5V lithium-ion cell, or to LixMn02 (3V vs. Li) to yield a 1.5V lithium-ion cell. Although these cells have a voltage lower than that of commercial... 

A. Gac, J.K. Atkinson, Z. Zhang, CJ. Sexton, S.M. Lewis, C.P. Please, and R. Sion, Investigation of the fabrication parameters of thick film titanium oxide-PVC pH electrodes using experimental designs. Microelectronics Int. 21, 44—53 (2004). 

X-ray diffraction conducted on the codeposited powder revealed that the deposit obtained from a suspension of gamma alumina, which had been partially converted to the alpha phase, contained both phases of alumina. Whereas, the powder codeposited from a suspension having a 50 50 mixture of alpha to gamma alumina powder, consisted only of the alpha phase. Using a parallel plate electrode configuration, Chen et al. [31] concluded that only alpha alumina can be codeposited. Chen also observed a difference in codeposition with copper when using two different phases of the titanium oxide particle system rutile readily codeposited but anatase titania did not... 

The principal advantage of the Beer coating, which is commercially available under the tradename of DSA , is its unique adherence to the base metal of the electrode because of the titanium oxide part of the coating. Refined DSA coatings of today have little in common with the first ruthenium Beer coatings. 

Protection layers between the titanium metal and the electrocatalytic coating, for example, of substoichiometric titanium oxides (see Ebonex above), increase the stability by shielding the metal, for example, to avoid the formation of insulating titanium dioxide layers on the metal [35]. The preparation of such electrodes with optimal properties usually needs the special know-how of commercial suppliers. 

Fig. 10-16. Polarization curves for anodic oxygen and cathodic hydrogen redox reactions on an n-type semiconductor electrode of titanium oxide in the dark and in a photoex-cited state i = anodic current in the dark (zero) = anodic current...

Figure 10-16 shows polarization curves observed for the anodic ox en reaction (anodic hole transfer) and for the cathodic hydrogen reaction (cathodic electron transfer) on an n-type semiconductor electrode of titanium oxide. The data in Fig. 10-16 show that the anodic current due to the transfer of holes (minority... 

The main competition to semi-condnctor photovoltaics for producing solar electricity commercially is coming from photoelectrochemical devices based on dye sensitisation. These devices use relatively inexpensive semi-conducting materials such as titanium dioxide, zinc oxide and tin oxide. Gratzel in Switzerland has carried out the seminal work in this area, following on from the initial observation by Fujishima and Honda in Japan that a titanium dioxide electrode could be used to spht water into hydrogen and oxygen. 

Based on cp-AFM evidence for the simple case of an n-alkanethiolate/Au SAM, the M structures show no evidence for penetration of metal to form conducting filaments that can cause shorts. The resultant junctions, however, do show extensive formation of reaction product layers with complex chemical compositions which may lead to unfavorable characteristics for molecular device operation. Indeed, in recent reports the use of Ti deposition on LB films, which contain water and inorganic salts at the bottom Pt electrode/LB film interface, leads to formation of inorganic titanium oxide type species in the junction but these complex inorganic layers have also been reported to impart fortuitously quite useful device... 

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