
Nanotechnology makes inroads in the construction industry - brandall10
http://nextbigfuture.com/2011/06/nanotechnology-makes-inroads-in.html
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zeteo
Yet another example of selling good old chemistry as nanotech. The
photocatalytic properties of titanium dioxide, also known as the Honda-
Fujishima effect, were discovered in 1967:

<http://en.wikipedia.org/wiki/Titanium_dioxide#Photocatalyst>

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gggritso
I wasn't aware of the photo-catalyst properties of bulk TiO2, so I'll have to
agree with you there, but I'll say two things in defence of the article.
Firstly, it does mention that a key factor in the effectiveness of TiO2 as a
catalyst is the exposed surface area, so nano-sized TiO2 may be necessary to
get the efficiency to make this viable. Perhaps bulk TiO2 just isn't enough.
Secondly, nano-sized TiO2 responds to light differently (for example, I just
did a lab experiment where TiO2 particles in nano behaved very differently
under XRD from bulk TiO2). There might be other benefits that nano TiO2 offers
that weren't mentioned in the article.

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zeteo
Nano-size doesn't seem to play a crucial role in this application. The article
is concerned with Italcementi's TX Active cement. Italcementi's main
development is a photocatalytic hydraulic binder, and here's their patent:

[https://data.epo.org/publication-
server/getpdf.jsp?pn=094645...](https://data.epo.org/publication-
server/getpdf.jsp?pn=0946450&ki=B1&cc=EP)

In the patent, they claim that

"Any kind of photocatalyst able to oxidize in the presence of light, air and
environmental humidity (oxygen and water) the polluting substances contacting
the surface of the hydraulic binder (or the relative mortars and concretes) in
a hardened state is part of the present invention, particularly a titanium
dioxide, mainly in the form of anatase, or a precursor thereof, optionally
doped with other atoms different from Ti."

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gggritso
I glanced at the patent, and it looks like you're right. It doesn't say much
about actual nano-properties at all.

