Doping with metals and non-metals is a popular technique that facilitates visible light activity of titanium dioxide. More recently, rare-earth metals have shown tremendous potential as dopants not only in red-shifting the absorption but also in improving the photocatalysis of TiO₂. This feature article discusses recent developments in making TiO₂ visible-light active through single and co-doping with rare earth metals. An emphasis is placed on wet chemical techniques and their associated effects on the phase, adsorption, surface area, and photocatalytic activity of TiO₂. New techniques, such as electrospinning, magnetron sputtering, co-precipitation, and complexation, as well as the use of nanotubes and physical support are also discussed.

In this study, a new approach to a uv-blocking treatment for cotton fabrics is developed using the sol-gel method. The treatment forms a thin layer of titania on the surface of cotton fibers, and the treated fabrics show much improved protection against UV radiation. with a UPF factor of 50+ or excellent protection according to the Australian/New Zealand standards. The treated fabrics are also tested for washfastness. The results show that the excellent uv protection rating of the treated fabrics can be maintained even after 55 home launderings, indicating a high level of adhesion between the titania layer and the cotton. A bursting strength test of the treated fabrics shows no adverse effect from the treatment.

Nanocrystalline titanium dioxide has been prepared under ambient pressure and at temperatures close to or approaching room temperature using hydrolysis of titanium tetraisopropoxide in an acidic aqueous solution. A transparent thin layer of nanocrystalline titania has been produced on cotton textiles by a dip-pad–dry-cure process. These TiO₂ coated cotton textiles possess significant photocatalytic self-cleaning properties, such as bactericidal activity, colorant stain decomposition and degradation of red wine and coffee stains. The UV absorption and tearing strength of the TiO₂ coated cotton has also been studied. Self-cleaning cotton may find potential commercialization in the textile industry.

While energy shortage is always an issue, the impending exhaustion of fossil fuel sources makes it an ever increasingly pressing one.