Aim of the project
The purpose of this project is the
synthesis and characterization of novel photocatalytic pigments prepared
using spray-drying and their further implementation into photocatalytic coatings.
The photocatalysts are primarily metal
oxide semiconductors than confer catalytic functionality to organic-based
coatings, as result of their combination with film forming agents, other
pigments, solvents and additives.
The motivation of
this project arises from the multiple applications of the resulting
photocatalytic coatings in environmental and health areas, including air
purification in highly polluted areas, self-cleaning coatings, and
The state-of-the-art of photocatalytic
coatings use titania nanoparticles (~21 nm) in anatase form, which is a wide
band gap semiconductor that acts as photocatalyst . Under UV irradiation
(< 400 nm) the coatings are able to create highly oxidizing species using
water and oxygen molecules that degrade pollutants (i.e., volatile organic
compounds (VOCs) and nitrogen oxides (NOx)) .
However, the performance of these
coatings is severely hindered because anatase is only active under UV light,
whereas sunlight and most common artificial light sources provide only minor
UV contribution . Another drawback for these coatings is the concomitant
photodegradation of the film forming agent that compromises the coating
stability. The toxicity of nanosized photocatalysts also imposes limitations
to many potential applications of photocatalytic coatings.
an established method within coatings technology widely used to produce
ordinary powder pigments. It can be used to produce microsized multishelled
particles with mesoporous structure with high surface area [4,5]. The use of
spray-drying for synthesis of photocatalytic pigments has not been fully
explored, but it is conceived that could lead to production of novel
photocatalysts, as an alternative to more established nanosized materials,
with higher performance and improved sustainability.
Description of the project
work will take place within the framework of The Hempel Foundation Coatings
Science and Technology Centre (CoaST).
The candidate will be responsible of
the laboratory-scale production of photocatalysts using spray-drying
technology. The structural, electronic and textural properties of the
synthesized materials will be characterized using morphology and spectroscopy
analysis techniques, whereas the photocatalytic activity will be asserted by
studying the kinetics of model reactions in artificial irradiation
spray-drying process parameters for photocatalysts production will be based
on the outcome of the structure and performance evaluation, which will allow
identifying structure-activity relationships. Finally, the most promising
photocatalysts will be ultimately used for formulation, characterization and
testing of photocatalytic coatings.
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