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EFFECT OF CHANGING THE WATER COMPOSITION IN THE
ELECTROLYTE ON THE MORPHOLOGY OF TiO2 NANOTUBE
Djumagulov Sh.KX.
Khamidov A.M.
Nurmanov S.E.
Rozimuradov O.N.
National University of Uzbekistan, Uzbekistan
Turin Polytechnic University in Tashkent
https://doi.org/10.5281/zenodo.15672677
The effect of varying H
2
O and F
-
concentration in electrolytes on TiO
2
morphology has been extensively studied. The effect of fluoride content during
anodization has little effect on nanotube diameter and oxide layer growth [1],
but leads to tube length, its growth rate, and higher order [2-3]. In contrast the
amount of water in the anodizing cell significantly increases the pore diameter,
but reduces the oxide expansion coefficient, pore length, growth rate and
efficiency. Electrochemical impedance spectroscopy (EIS) was used to monitor
the growth of the barrier layer formed during the anodization of TiO
2
in an
electrolyte containing F
-
ions, which also allowed us to study the effects of the
concentration of F
-
ions in the solution and the pH medium of the electrolyte. [4-
5].
Research results
The formation of TiO
2
nanotubes depends on various factors, one of which
is the chemical aggressiveness of the medium, since the formation of nanotubes
from nanoporosity requires the dissolution of Ti oxofluorides formed between
the tube walls.
During the anodizing process, when a voltage of 0 to -0.8V is applied, an
increasing H
2
O content in the electrolyte from 1.0 to 5.0 % leads to a significant
increase in the aggressiveness of the medium, while significantly reducing the
time spent on dissolving the oxide layer on the electrode surface. The scan rate
was set to a constant value of 20 mV/s, and the half-wave potential E(V)-(-0.7 V)
was observed in the electrolyte containing 1% H
2
O, starting at 10 seconds and
giving an analytical signal of -1.36 V, at 210 seconds, with a 5% H
2
O content,
E(V)-(-0.82 V) was observed in the electrolyte containing 9.7 seconds and giving
an analytical signal of -1.38 V, at 146.38 seconds, with a 10 % H
2
O content, E(V)-
(-0.63 V) was observed in the electrolyte containing 10 % H
2
O, E(V)-(-0.64 V)
was observed in the electrolyte containing 25% H
2
O, E(V)-(-0.64 V) was
observed in the electrolyte containing 9.9 seconds and giving an analytical signal
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of -1.36 V, at 147.4 seconds, and It can be seen that in the presence of 50 % H
2
O,
E(V)-(-0.83 V) starts at 10.21 seconds and gives an analytical signal of -1.48 V at
5.2 seconds. Considering the above results, it was shown that in the electrolyte
containing 0.20M NH
4
F, when 5% H
2
O was present, the formed nanotubes were
highly ordered and had flat surfaces. When 1% H
2
O was present, the nanotubes
were not highly ordered and not fully formed, and when 10% H
2
O was present,
the nanotubes were not fully formed. In the presence of H
2
O, nanotubes with a
non-highly ordered structure are formed, in the presence of 25% H
2
O nanotubes
with a non-uniform diameter are formed, and in the presence of 50% H
2
O
nanotubes with a non-highly ordered structure are formed with a large diameter
(Fig. 1a).
Initially, the main reason for the increase in current with increasing
concentration is that there are enough charge carriers in the solution, and the
charges move more, which leads to an increasing in the analytical signal. After a
certain amount, the excess charge carriers increase and, as a result, the density
of the charge movement paths slows down the diffusion. As a result, the
analytical signals become smaller. Important factors affecting on electrical
conductivity are the mobility of ions or electrons and the internal structure of
the materials.
Figure 1.
Time-dependent half-wave potential of electrolytes consisting of
a) 0.2M NH
4
F (1, 5, 10, 25, 50%) H
2
O and ethylene glycol, b) 1% H
2
O (0.05, 0.10,
0.20, 0.35, 0.50 M) NH
4
F and ethylene glycol
Referanses:
1.
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MODELS AND METHODS IN MODERN SCIENCE
International scientific-online conference
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