TiC>2 films

This is comparable to or slightly higher than the values reported for single crystal (11) and polycrystalline Ti02 (12), and much higher than those for the TiC>2 film electrode prepared by other methods such as chemical vapor deposition (13) and oxidation (14) and anodization (15) of Ti metal. The high efficiency of the dip-coated Ti(>2 film may be attributed to the porous nature of the film as described below. 

The perylene chromophotes were modified by covalently attaching different side groups. Two bulky groups (tertiary-butyl), indicated by a prime, prevented dimerization of neighbouring perylene chromophores when attached to the surface. Linkage to the semiconductor was achieved by different anchor-cum-spacer groups carbonic acid (-COOH) [4], propionic acid (-CH2-CH2-COOH) [2], phosphonic acid (-P(0)(OH)2) [4], methyl-phosphonic acid (-CH2-PO(OH)2) [2] and a -Tripod (see inset in Fig.2) [5], The preparation and sensitization of the nano-structured TiC>2 film and further experimental details have been described before [2]. 

In a similar way, a well-adhered surface modification of BC fibers can be achieved with Ti(>2 nanoparticles (with a diameter of about 10 nm) by the hydrolysis of titanium tetraisopropanolate adsorbed onto the fibers. It was observed that the titania-coated surface appears to be dense and have low porosity and to consist of near-spherical grains. By washing with sodium carbonate solution, the TiC>2 films were not removed during neutralization. It seems that the particles have formed strong interactions with BC. The coated membranes showed substantial bactericidal properties under UV radiation and white light (containing a small fraction of UV) conditions, too. This effect is caused by the photocatalytic destruction of the bacterial cells. 

Fig. 15 Photocurrent action spectra of nanocrystalline TiC>2 films sensitized by complexes 2, 25, and 26. The incident photon to current conversion efficiency is plotted as a function of wavelength...

Figure 6.5 Pore size distribution in a nanocrystalline TiC>2 film as determined by nitrogen adsorption. Reprinted from P. Bonhote, E. Gogniat, S. Tingry, C. Barbe, N. Vlachopoulos, F. Lenzmartn, P. Comte and M. Gratzel, ]. Phys. Chem., B, 102,1498 (1998). Copyright (1998)...

Surface activation of BMI coupons was done by rinsing in organic solvents followed by UVOCS activation for 20 minutes. This was essential for good TiC>2 film adhesion. 

Samples of BMI dried using variable humidity were analyzed by SEM and the degree of film cracking was calculated using image analysis software (Table 2). Controlled humidity drying at 60 or 70°C provided nearly crack free amorphous TiC>2 films (Method 1). Crystalline films (Method 2) needed to be dried at 70°C. Controlled humidity drying of the amorphous films at elevated... 

The presence of oestrogenic compounds in potable water supplies has also raised concerns in recent years. The destruction of 17-/i-oeslradiaol on immobilised TiC>2 films has been achieved with 98% decomposition observed in 3.5 h photocatalysis [169]. 

Measured for carbon-doped TiC>2 films with Xe-lamp irradiation at 40 mW/cm2. However, see text. 213... 

TiC>2 films produced by oxidizing Ti films, which contain the cubic phases TiO and TiN, ( = 4.23 A, a = 4.166 A), by tempering in air between 400°C and 450°C show solely tetragonal anatase (a = 3.73 A, c = 9.37 A). Only after heat treatment at 600°C are rutile diffraction rings also obtained in addition to anatase rings from the 2 films thus produced [27]. 

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