ISSN 1070-4272, Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 5, pp. 547−554. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © I.I. Lebedeva, I.P. Sizeneva, D.M. Kisel’kov, V.A. Val’tsifer, 2014, published in Zhurnal Prikladnoi Khimii, 2014, Vol. 87, No. 5, pp. 554−562.
INORGANIC SYNTHESIS AND INDUSTRIAL
Study of the Effect of Ammonium Sulfate Additives
on the Structure and Photocatalytic Activity of Titanium Dioxide
I. I. Lebedeva, I. P. Sizeneva, D. M. Kisel’kov, and V. A. Val’tsifer
Institute of Technical Chemistry, Ural Branch, Russian Academy of Sciences,
ul. Akademika Koroleva 3, Perm, 614013 Russia
Received November 29, 2011
Abstract—Thermal hydrolysis of titanium hydrochloride in the presence of ammonium sulfate added in
a Ti : SO
= 20 : 1 ratio was used to obtain samples of mesoporous titanium dioxide with anatase structure, stable
in a wide temperature range. The phase composition, porous structure, and morphology of the synthesized titanium
dioxide powders were examined by X-ray phase analysis, IR spectroscopy, scanning electron microscopy, and low-
temperature adsorption of nitrogen. The role played by sulfate ions in how the microstructure of titanium dioxide
is formed was determined. The effect of the hydrolysis temperature on the structure of titanium dioxide being
obtained and on its photocatalytic activity in the reaction of decomposition of Methyl Orange dye was examined.
Nanocrystalline materials based on titanium dioxide
ﬁ nd wide use in manufacture of photocatalysts, gas sen-
sors, and dielectric ceramics. The photocatalytic activity
and the reactivity of titanium dioxide are determined by its
phase composition, size and shape of particles, and struc-
ture and size of pores . The possibility of controlling
the phase composition and texture properties is largely
determined by the wide variety of starting substances,
lability of compounds being formed, and diversity of
affecting factors and synthesis methods .
As an accessible raw material for obtaining titanium
dioxide, produced in the world in rather large amounts,
serve oxotitanium sulfate solutions used in manufacture of
pigment-type titanium dioxide and titanium tetrachloride
used in production of spongy titanium . The application
of titanium alkoxides is restricted by their high cost. At
present, Russia produces in sufﬁ ciently large amounts
only titanium tetrachloride and, therefore, its use to obtain
photocatalytically active titanium dioxide is promising .
The most widely employed method for obtaining tita-
nium dioxide is by thermal hydrolysis of its salt solutions,
followed by drying and thermal treatment. The main ad-
vantage of this method is in the possibility of controllably
varying the synthesis conditions, which yields titanium
dioxide with various kinds of structure and quantitative
phase ratios (amorphous titanium dioxide, anatase, rutile,
or brookite). Titanium dioxide with only anatase structure
is obtained from sulfate compounds of titanium, whereas
structures of both anatase and rutile types can be formed
from chloride and nitrate compounds.
Rutile is a more thermodynamically stable modiﬁ ca-
tion of titanium dioxide, which also valid for products
formed in thermal hydrolysis. Therefore, the formation
of an anatase or a rutile structure is also determined by
kinetic factors. Titanium(IV) has in the condensed state
an octahedral coordination, the lattice of rutile and anatase
is constituted by TiO
octahedra linked in a certain way.
The octahedra are bound at their vertices when anatase
is formed, and at edges in the case of rutile.
When the structure is formed in hydrolysis, an octa-
hedrally coordinated complex is attached to the surface of
a nucleus. Each anatase octahedron has four common edg-
es with neighboring octahedra, with their zigzag chains
connected layer-by-layer at their vertices. A structure of
this kind can be formed in crystallization from solution
via cross-linking of polymer chains or via attachment
of separate octahedra by their vertices to these chains.
Titanium dioxide cannot be formed as rutile in sulfate