Metal doped TiO
2
: the effect of NH
3
exposure on structural and photocatalytic
properties
Papadaki D.
a,b
, Binas V.
a,d
, Gupta B.
c
, Lipton-Duffin J.
c
, Motta N.
c
, Kiriakidis G.
a,d
a
Institute of Electronic Structure & Laser (IESL) Foundation for Research and Technology
(FORTH)100, N. Plastira str, Vassilika Vouton GR-70013 Heraklion, Crete, Greece
b
Environmental Engineering Department Technical University of Crete GR-73100 Chania,
Greece
c
Queensland University of Technology, Brisbane, Australia.
d
Crete Center for Quantum Complexity and Nanotechnology, Physics Department University
of Crete Vassilika Vouton, GR-71110 Heraklion, Crete, Greece
Corresponding author
Titanium dioxide nanopowders of various dopants were prepared using modified sol-gel
method. TiO
2
was doped at concentration rate of 1%, with transition metals (such as Mn, Co
and Fe), and poor metals (such as Al, and In). A comparative study of their photocatalytic
activity in relation with structural characterization, with and without the presence of NH
3
gas,
is presented here. The obtained powders were characterized by X-ray diffraction (XRD), and
Ultraviolet–visible spectroscopy (UV−Vis). Their morphologies have been studied using
scanning electron microscopy (SEM), whereas their photocatalytic performance was studied
under UV and Visible irradiation on the decolourization of methylene blue (as test model
dye). A detailed analysis though X-ray Photoelectron Spectroscopy (XPS) is presented and
the introduction of NH
3
gas in situ was conducted for the first time inside the chamber of the
XPS. The highest grain size was found in the sample of TiO
2
:Co, where it was found to be
43.48nm and the smallest in TiO
2
:In , 19.57nm. XPS measurement showed several
differences of the binding energy and changes of oxidation states after NH
3
exposure. The
highest photocatalytic performance was found to be 41.9% for TiO
2
:Co under Visible
Irradiation, whereas under UV all samples showed a degradation of around 15%.
O 51
-117-
