Solution titania coatings

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. 

PZC/IEP of PZC/IEP of Titania Coating on Silica Deposited from TiCl4 Solution... 

An example of a photochemical cyclization was reported by Takei et al. [92], who demonstrated the synthesis of L-pipecolinic acid (160) from an aqueous solution of L-lysine (161), as illustrated in Scheme 6.42. To achieve this photocatalytic transformation, the authors fabricated a Pyrex micro reactor in which the channel cover plate was coated with a 300nm layer of anatase Ti02 (100 nm particles), to afford a titania-coated micro reactor (TCM) the titania film was subsequently loaded with platinum (0.2 wt%), by photodeposition, to enable the TCM to be used... 

The microemulsion method has also been used for preparing titania-coated silica particles [273]. The silica particles were produced by injection of tetraethyl orthosilicate into a reverse microemulsion composed of the system Triton X-45/ cyclohexane/aqueous solution of ammonia or sulfuric acid. As already mentioned, the Triton X series of products can be described as alkylaryl polyether alcohols, the numbers indicating the average number of ethylene oxide units (5 in case of Triton X-45). Formation of silica took place by hydrolysis and condensation through controlled time periods. 

Frey M.H., Payne D.A. Synthesis and processing of barium titanate ceramics from alkoxide solutions and monolithic gels. Chem. Mater. 1995 7 123-129 Fu X., Qutubuddin S. S)mlhesis of titania-coated sMca nanoparticles using a nonionic water-in-oil microemulsion. Colloids Surf. A 2001 179 65-70 Ganguli D. Sol-emulsion-gel synthesis of ceramic particles. Bull. Mater. Sd. 1999 22 221-226 GanguU D., Chatteijee M. Ceramic Powder Preparation A Handbook. Boston Kluwer Academic Publishers, 1997... 

Figure 12-4. Reduction in thickness on heat-treatment for titania coatings prepared on single-crystal Si substrates from solutions with and without chelating agents (Ishikawa, 2004a, 2004b).

Efficient intracellular delivery of the anticancer drug camptothecin (CPT) by hollow silica/titania nanoparticles has been reported [114]. Monodispersed hollow nanoparticles (about 50 nm) were prepared by titania coating of Stober silica particles followed by silica dissolution and redeposition in an ammonia solution (Figure 11.13). Surface modification of these particles with an antibody herceptm, a... 

The support material used is a titania-coated sihea (Ti-Si). This titania-coated sihea is prepared by deposition-anchoring of Ti02 from ethanolic solutions of Ti[0(CH2)3CH3]4 alkoxide over Si02. The silica support (aerosil, Sbet=482 m -g ) is suspended in ethanol (250 ml/g support) and the amount of alkoxide to reach a Ti/-OH ratio of 3 is added. 

Kraemer, S.M. Hering, J.G. (1997) Influence of solution saturation state on the kinetics of ligand-controlled dissolution of oxide phases. Geochim. Cosmochim. Acta 61 2855-2866 Kraemer, S.M., Xu, J., Raymond, K.N. Spo-sito, G. (2002) Adsorption of Pb(II) and Eu(III) by oxide minerals in the presence of natural and synthetic hydroxamate sidero-phores. Environ. Sd. Technol. 36 1287-1291 Kraemer, S.M. Cheah, S.-F. Zapf, R. Xu, J. Raymond, KN. Sposito, G. (1999) Effect of hydroxamate siderophores on Fe release and Pb(II) adsorption by goefhite. Geochim. Cosmochim. Acta 63 3003—3008 Kratohvil, S. Matijevic, E. (1987) Preparation and properties of coated uniform colloidal partides. I. Aluminum (hydrous) oxide on hematite, diromia, and titania. Adv Ceram. Mater. 2 798-803... 

Silica has been used both as a core and shell material. For example, monodis-persed silica spheres were coated with titania by decomposing titanyl sulfate, TiOS04, in acidic solutions at 90°C (146). The particles so produced showed good hiding power, to be useful as paper whiteners (147). Due to the uniformity of the cores and shells, the optical properties of such dispersions were predictable and reproducible, as shown in Figure 1.1.22, which compares the scattering coefficient,... 

The pore doping approach has also been successful in maintaining small NC size dispersities. Initially, porous dip-coated alumina and titania films were fabricated and then directly immersed into aqueous solutions of NaAuCl4-2H20 so that the AuCLt ions could be incorporated into the pores of... 

In a similar approach, titania composites doped with CdSe and CdSe/ZnS NCs were prepared. Here the NCs were mixed with titanimn tetrabntoxide in a 2 1 THF/ethanol solvent system, and volnme fractions as high as 13% were reported in films that were spin-coated from the sol solutions. While QYs for the CdSe/ZnS-titania sols remained near 10%, smaller valnes were reported for CdSe NCs that were not initially overcoated with ZnS. In addition, the samples were not very stable, as the PL intensity was observed to decrease in the films almost immediately following processing. 

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