Concrete, mortar and plaster using titanium dioxide nanoparticles: applications in pollution control, self-cleaning and photo sterilization - Nanotechnology in Eco-efficient Construction - page 300

Vis

UV IR

250 500 750 1000 1500

Wavelength (nm)

1250 1750 2000 2250 2500

13.2 Spectral irradiance of sunlight as a function of wavelength,
highlighting ultraviolect (UV), visible (Vis) and infrared (IR) fractions.

Photoinduced
superhydrophilicity

Self-cleaning

Titanium dioxide

Antivegetative

Photocatalysis

Degradation of
liquid pollutants
(wastewaters)

Degradation of
gas pollutants
(air treatment)

Antibacterial
(disinfection)

13.3 Main effects connected with TiO 2 photoactivity.

with the reasons for its success in such different environments. Before that,
a brief look at other semiconductors that can be used as photocatalysts is
required for a comprehensive treatise.

￿ ￿ ￿ ￿ ￿ ￿

13.2.3 Other photocatalysts

Titanium dioxide is by far the most studied photocatalyst, but several works
are also dedicated to the study of other transition metal oxides and to the
evaluation of their semiconducting nature and consequent photocatalytic
activity. Probably the most important reason for this broadening of the
sector is the fact that titanium dioxide can only be activated by UV light,
which occupies a very narrow percentage of natural light: the choice of a
photocatalyst which is active under visible light would allow a wider slice
of sunlight to be exploited, and therefore increase the material effi ciency.