Fabrication of TiO2 Nanoparticles by electrostatic jet using the low dielectric constant solvent

Article abstract of DOI:10.1166/jnn.2016.12167

Tert-butyl alcohol (TBA) was used as a low dielectric constant solvent for the fabrication of TiO₂ nanoparticles by electrostatic jet. The phase, morphology and diameter distribution properties of the resulting TiO2 nanoparticles were characterized by XRD and SEM, respectively. As the PVAc content of the precursor solutions increased, the diameter of the electrostatic jet PVAc/butyl titanate composite nanoparticles increased. The resulting composite nanoparticles possessed a smooth surface and displayed perfect spherical structures when the PVAc content was 3 wt%, where as a PVAc content of 9 wt% or more led to a co-continuous structure of nanoparticles and fibers, other were erythrocyte-liked in shape and contained large pits on their surface. Anatase TiO₂ nanoparticles were formed from the butyl titanate/PVAc nanoparticles following their calcination at 550 °C. The diameter distribution of the TiO₂ nanoparticles was wide, with the values falling in the range of 623-8±122-8 to 1328-3±247-6 nm. When its diameter is 238 nm and adding content is 2 g/L, the 40 min degradation rate of methylene blue catalyzed by titanium oxide nanoparticles is 92.39%.

Full text of DOI:10.1166/jnn.2016.12167

Article
Journal of
Nanoscience and Nanotechnology
Vol. 16, 9943–9950, 2016
Copyright © 2016 American Scientific Publishers
All rights reserved
www.aspbs.com/jnn
Printed in the United States of America
Fabrication of TiO2 Nanoparticles by Electrostatic Jet
Using the Low Dielectric Constant Solvent
Yufei Tang∗, Heng Zhang, Kang Zhao, Gaowei Xie, Letian Teng, and Zhaowei Liu
School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, P. R. China
Tert-butyl alcohol (TBA) was used as a low dielectric constant solvent for the fabrication of TiO2
nanoparticles by electrostatic jet. The phase, morphology and diameter distribution properties of
the resulting TiO2 nanoparticles were characterized by XRD and SEM, respectively. As the PVAc
content of the precursor solutions increased, the diameter of the electrostatic jet PVAc/butyl titanate
composite nanoparticles increased. The resulting composite nanoparticles possessed a smooth
surface and displayed perfect spherical structures when the PVAc content was 3 wt%, where as a
PVAc content of 9 wt% or more led to a co-continuous structure of nanoparticles and fibers, other
were erythrocyte-liked in shape and contained large pits on their surface. Anatase TiO2 nanopar-
ꢀ
ticles were formed from the butyl titanate/PVAc nanoparticles following their calcination at 550 C.
The diameter distribution of the TiO2 nanoparticles was wide, with the values falling in the range of
623ꢀ8 122ꢀ8 to 1328ꢀ3 247ꢀ6 nm. When its diameter is 238 nm and adding content is 2 g/L, the
40 min degradation rate of methylene blue catalyzed by titanium oxide nanoparticles is 92.39%.
Delivered by Ingenta to: Deakin University Library
IP: 191.101.54.140 On: Sun, 07 Aug 2016 08:38:01
Keywords: Electrostatic Jet, TiO2, Nanoparticles, Photocatalytic Property.
Copyright: American Scientific Publishers
1. INTRODUCTION
The electrostatic jet method itself involves the genera-
tion of low-dimensional materials (ultrafine droplets) with
sizes in the micron to nanometer range.16–19 Solvents such
as N ,N -dimethylformamide (DMF), ethanol and deion-
ized water are generally used for electrostatic jet.20 Spher-
ical nanoparticles are typically generated by decreasing
the molecular weight of the polymer as well as its con-
centration in the precursor solution (<5 wt%), and opti-
mizing the voltage and the flow rate properties of the
precursor solution. Wu et al.21 reported the synthesis of
polycaprolactone (PCL) polymer particles via electrostatic
jet using 1–4 w/v% solutions of PCL (Mw = 10ꢀ000) in
chloroform. Zheng et al.22 constructed polystyrene (PS)
nanoparticles by electrospinning or electrospraying from
a solution of PS in a mixture of DMF and tetrahydrofu-
ran (THF). The products resulting from the electrostatic jet
method, however, are predominantly irregular particles or
fibers, with nanoparticles only being formed in low yields.
To fabricate nanoparticles by electrostatic jet, as well as
considering and taking account of the requirements for
polymerization, the solvent used in the precursor solution
must possess certain characteristics, such as a poor sol-
ubility for the resulting polymer, low dielectric constant,
high volatility, and suitable surface tension. In this way,
TiO2 nanoparticles are ceramic particles with diameters in
the nanometer range. Based on their nano-spherical struc-
ture, it has been suggested that TiO2 nanoparticles could be
used in a number of different areas, including sewage treat-
ment and air purification systems, as well as dye-sensitized
solar cells (DSC) and lithium ion batteries, because of their
large surface area, small particle diameter and excellent
chemical stability.1ꢀ2 The successful application of TiO2
nanoparticles in these areas is heavily reliant upon the syn-
thesis of TiO2 nanoparticles in the micron to nanometer
scale to expand the reaction area, shorten the Li+ diffu-
sion distance and increase the packing density.3ꢀ4 There
have been a large number of reports in the literature con-
cerning the fabrication of TiO2 nanoparticles by a variety
of different methods, including the sol–gel process,5 elec-
trochemical method,6 hydrothermal synthesis,7 ultrasonic
spray pyrolysis,8 and electrostatic jet (electrospinning or
electrospraying).9–15
Electrostatic jet was recently demonstrated as a use-
ful method for the production of ceramic nanoparticles.
∗Author to whom correspondence should be addressed.
J. Nanosci. Nanotechnol. 2016, Vol. 16, No. 9
1533-4880/2016/16/9943/008
doi:10.1166/jnn.2016.12167
9943

Fabrication of TiO2 Nanoparticles by Electrostatic Jet Using the Low Dielectric Constant Solvent
Tang et al.
research in this area could provide new ideas for the prepa-
ration of nanoparticles by electrostatic jet.
dielectric spectrometer (Concept 80, NOVOCONTROL
Technologies GmbH & Co. KG, Montabaur, Germany),
and the frequency is 103 Hz. The viscosity of precur-
sor solution was measured with a viscometer (SNB-2,
Shanghai Nirun Intelligent Technology Co., Ltd, Shanghai,
China). The conductivity measurements were recorded on
a conductivity meter (DDS-307, INESA.CC, Shanghai,
China), and the surface tension properties were mea-
sured using a surface tension meter (SKJK99B, Shanghai
Zhiheng instrument, Shanghai, China). The temperature
range for the calcination was determined by assessing
changes in the sample weight change during the calcina-
tion process using a thermo gravimetric analyzer (WRT3P,
Shanghai Precision Instrument Co. Ltd., Shanghai, China).
X-ray diffraction (XRD; Model 7000, Shimadzu Limited,
Japan) analysis was used to identify the phases present
in the sintered samples. The diameters of spheres were
determined by measuring the surfaces of the samples in
the SEM images using a digital imaging tool (Commer-
cial software, version 2.0, Digital Liquid Ltd., Canada),
with fifty samples being tested in this way to obtain
an average value. The nanoparticles were characterized
by N2 adsorption at 77 K using a model BK122T-B
analyzer. The surface area of nanoparticles was evalu-
ated by the Brunauer-Emmett-Teller (BET) model, while
the pore size and pore volume were estimated with
Barrett-Joyner-Halenda (BJH) theory23 according to the
GBT 21650.2-2008. The degradation products were char-
acterized by a Gas Chromatography-mass Spectrometer
(GCMS) (QP2010 Ultra, SHIMADZU, Japan), and inor-
ganic ions in the degradation products were determined
using a ionic chromatographer (761 Compact, Switzerland
Metrohm Co., Switzerland).
In the current study, we attempted to fabricate TiO2
nanoparticles by electrostatic jet using tert-butyl alcohol
(TBA) as the solvent because TBA is volatile and has a
low dielectric constant. The resulting nanoparticles were
erythrocyte in shape and contained large pits on their sur-
face. The viscosity, conductivity and surface tension prop-
erties of the precursor solution could be easily controlled
by adjusting the PVAc content in the TBA. Nanoparticles
with different size and morphology characteristics were
obtained depending on the physical properties of the pre-
cursor solutions. The phase, morphologies and diameter
distribution properties of the resulting TiO2 nanoparti-
cles were also characterized. Additionally, the photocat-
alytic properties are analyzed in terms of methylene blue
decomposition rates. The results indicate that the TiO2
nanoparticles could be used for removal of pollutants in
wastewater.
2. EXPERIMENTAL PROCEDURE
Butyl titanate (AR, Tianjin Kermel Chemical Reagent Co.,
Ltd., Tianjin, China) was used as a titanium precursor
and tert-butyl alcohol (TBA, AR, Tianjin Kermel Chemi-
cal Reagent Co., Ltd.) was used as a solvent. Poly(vinyl
acetate) (PVAc, Mw = 100ꢀ000) was purchased from
Delivered by Ingenta to: Deakin University Library
Sigma Aldrich (Milwaukee, Wisconsin, U.S.). Acetic acid
IP: 191.101.54.140 On: Sun, 07 Aug 2016 08:38:01
(AR, Tianjin Kermel Chemical Reagent Co., Ltd.) was
Copyright: American Scientific Publishers
used as a chelating agent and to reduce the degree of
cross-linking.
A solution of PVAc in TBA (10 mL) was prepared by
vigorously stirring the two materials for 4 h. A mixture of
butyl titanate (5 mL) and acetic acid (5 mL) was added to
the PVAc solution with stirring over a period of 2 h and
the resulting mixture was aged for 12 h to give precursor
solutions with PVAc contents of 1, 3, 5, 7, 9, and 11 wt%.
The individual precursor solutions were then placed in
the micropump of an electrostatic jet apparatus (KH-08,
Beijing Kangsente Co. Ltd, Beijing, China), which was
used as an injector bearing a metal nozzle with a diam-
eter of 0.7 mm. The power supply was connected to the
metal nozzle. A voltage of 18 kV was used together with a
flow rate of 0.318 mL/h. The distance from the nozzle tip
to the collector was 15 cm. PVAc/butyl titanate compos-
ite nanoparticles were obtained by electrostatic jet using
a plate collector. The samples were subsequently dried at
Photocatalytic activity was determined by dispersing the
titanium oxide nanoparticles (25, 50, 75, 100, 125 mg) in
50 ml of methylene blue solution (10 mg/L). Photocat-
alytic decomposition of the methylene blue was carried
out in a quartz cuvette under ultraviolet light (365 nm)
for 40 min, and then analyzed by absorption changes at
665 nm using a UV-visible absorption spectrometer. The
photodecomposition rate D of the methylene blue was cal-
culated from Eq. (1), A0 is the initial concentration of
methylene blue and A is its concentration at different irra-
diation times.
D = ꢁꢂAo −Aꢃ/Aoꢄ×100%
(1)
ꢀ
70 C for 6 h to remove any residual TBA. The dried
3. RESULTS AND DISCUSSION
composite nanoparticles were sequentially calcined at 500,
Figure 1 shows the morphologies of the butyl titanate/
PVAc composite nanoparticles generated by electrostatic
jet using PVAc solutions containing 1, 3, 5, 7, 9, and
11 wt% PVAc. The PVAc contents of the precursor
solutions affected the formation,24 density, morphology
and diameter properties of the resulting nanoparticles.
As shown in the SEM images, the composite nanoparti-
cles were only obtained when the PVAc content of the
ꢀ
550, and 600 ꢀC at a rate of 5 C/min for 2 h to afford the
TiO2 nanoparticles with furnace cooling.
The morphologies of the resulting nanoparticles were
characterized by SEM (JSM 6700, OLYMPUS, Tokyo,
Japan) and TEM (JEM-3010, JEOL, Tokyo, Japan). The
dielectric constant of TBA and precursor solutions with
different PVAc contents was determined by broadband
9944
J. Nanosci. Nanotechnol. 16, 9943–9950, 2016

Tang et al.
Fabrication of TiO2 Nanoparticles by Electrostatic Jet Using the Low Dielectric Constant Solvent
Figure 1. Morphologies of the butyl titanate/PVAc nanoparticles with various PVAc contents: (a) 1 wt%; (b) 3 wt%; (c) 5 wt%; (d) 7 wt%; (e)
9 wt%; (f) 11 wt%.
precursor solution was 7 wt% or lower, and the diame-
ter of the composite nanoparticles increased with increas-
ing PVAc content. Butyl titanate/PVAc composite fibers
began to form at a PVAc content of 9 wt% and the diam-
eters of the composite nanoparticles were decreased. The
number of composite fibers and the diameter increased
sharply when the PVAc content reached 11%. Further-
precursor solutions with different PVAc contents. Dielec-
tric constants are increased slightly with increasing the
PVAc content but their values retain at about 13. The
low values of the dielectric constant remain the same
in the mixture of TBA/PVAc with different concentra-
tion, which has been used for the nanoparticle preparation.
These results indicate that the charge carrying capability
of a droplet in the nozzle would be weak, and result in
the formation of spherical jet products because of the low
traction of the electric force on the droplet. Furthermore,
TBA has a high vapor pressure, low boiling point and suf-
ficient surface tension, making it a suitable solvent for the
construction of nanoparticles.
The transesterification of PVAc and TBA occurs in the
polymer solution system to form interchain links.25 Butyl
titanate has been used as catalyst for the transesterifica-
tion of PVAc, as shown in Eq. (1). The cross-linking of
PVAc through transesterification reactions results in the
formation of a material with high viscosity and surface
tension properties. It is difficult to generate nanoparticles
by electrostatic jet, and acetic acid was therefore used as a
chelating agent of butyl titanate to reduce the cross-linking
of PVAc.26
Delivered by Ingenta to: Deakin University Library
more, the SEM images of the resulting composite nanopar-
IP: 191.101.54.140 On: Sun, 07 Aug 2016 08:38:01
ticles revealed that their surfaces were porous and that
Copyright: American Scientific Publishers
they possessed an erythrocyte-like surface morphology.
When the PVAc content was 3 wt%, the resulting com-
posite nanoparticles possessed smooth surfaces and were
perfectly spherical in shape. These differences in the prop-
erties of the composite nanoparticles were attributed to
the properties of the precursor solution (e.g., the proper-
ties of TBA, solution viscosity, conductivity and surface
tension).
TBA is the poor solvent for PVAc, and the proper-
ties of TBA are shown in Table I. The swelling of the
PVAc molecular chains in TBA was found to be inade-
quate, and the concentration of molecule tangles occurring
in TBA was therefore generally higher than that observed
in several other good solvents. The dielectric constant and
conductivity properties of TBA were lower than those of
ethanol and DMF. Table II shows the dielectric constant of
Table II. Dielectric constant of precursor solutions with different PVAc
contents.
Table I. Properties of tert-butyl alcohol.
PVAc content of precursor
Type of solvent
Tert-butyl alcohol
solutions/wt%
Dielectric constant
Solubility
Poor solvent
11ꢅ4
1
3
5
7
9
11
13.7
13.2
12.5
13.1
13.0
12.9
Dielectric constant
Conductivity/ꢆs·cm−1
Vapor pressure/kPa (20 ꢀC)
Boiling point/ꢀ C
Surface tension/mN·m−1
29ꢅ0
4ꢅ08
82ꢅ42
23ꢅ6
J. Nanosci. Nanotechnol. 16, 9943–9950, 2016
9945

Fabrication of TiO2 Nanoparticles by Electrostatic Jet Using the Low Dielectric Constant Solvent
Tang et al.
OH
C
[CH2
CH ]
n
CH3
CH3
+
O
C
O
CH3
CH3
CH3
C
CH
OH
CH3
CH3
C
O
CH
O
[
]
n
+
2
CH3
(2)
Figure 2 shows the viscosity, conductivity and surface
tension properties of the different precursor solutions con-
taining different amounts of PVAc. Increases in the PVAc
content of the precursor solution led to increases in its
viscosity, as well as a decrease in its conductivity. These
changes, however, had no discernible impact on the sur-
face tension of the precursor solution. The viscosity is an
important factor because it affects the morphology of the
nanoparticles.27 However, when the PVAc content of the
precursor solution was less than 7 wt%, the surface ten-
sion was the main factor controlling the morphology of
the nanoparticles. It is not possible for the solution in the
nozzle to avoid the action of an external force, with the
solution effectively being broken into droplets because of
insufficient levels of molecular chain entanglement. Spher-
ical nanoparticles were formed by the viscoelasticity of
Figure 3. TG-DTG curves of butyl titanate/PVAc nanoparticles with a
3 wt% PVAc content.
12.32 to 8.12 ꢆS · cm−1 with increasing PVAc content
because of the transesterification of PVAc and TBA and
the poor solubility of PVAc in TBA. The formation of
nanoparticles was promoted because the solution was
stretched inadequately in terms of the electric force and
the low conductivity. Rosell-Llompart et al.29 reported that
the relationship between the droplet size and the properties
of the precursor solution could be expressed according to
the flowing equation:
ꢀ
ꢁ
1/3
Qꢇꢇ0
K
D = Gꢂꢇꢃ
(3)
Delivered by Ingenta to: Deakin University Library
the PVAc molecular chain and the surface tension of the
d
IP: 191.101.54.140 On: Sun, 07 Aug 2016 08:38:01
droplet. When the PVAc content of the precursor solu-
Copyright: American Scientific Publishers
Where Dd is the diameter of the droplet, Q is the flow
rate, ꢇ is the dielectric constant of the precursor solution,
ꢇ0 is the dielectric constant of a vacuum, K is the conduc-
tivity of the precursor solution, and G is a constant that is
tion became greater than 9 wt%, fibers formed between
the nanoparticles and the entangled PVAc molecules that
were joined by the electric force because of the degree
of entanglement between the molecular chains. This led
to an increase in the relaxation time of the surface ten-
sion of the solution, which resulted in the formation of a
co-continuous structure of nanoparticles and fibers.
The conductivity of the precursor solution is also con-
sidered to be a key factor in terms of its affects on the
morphology of the nanoparticles.28 As shown in Figure 2,
the conductivity of the precursor solution decreased from
Figure 2. Viscosities, conductivities and surface tensions of the precur-
Figure 4. XRD patterns of the TiO2 nanoparticles calcined at different
sor solutions with different PVAc contents.
temperatures.
9946
J. Nanosci. Nanotechnol. 16, 9943–9950, 2016

Tang et al.
Fabrication of TiO2 Nanoparticles by Electrostatic Jet Using the Low Dielectric Constant Solvent
Figure 5. Morphologies of TiO2 nanoparticles made using precursor solutions with different PVAc contents: (a) 1 wt%; (b) 3 wt%; (c) 5 wt%;
(d) 7 wt%; (e) 9 wt%; (f) 11 wt%.
mainly dependent on ꢇ, as well as the viscosity and the
surface tension of the precursor solution. From Eq. (2),
it is clear that the effects of the properties of the precur-
sor solution on the droplet size can be attributed to K.
As the PVAc content of the precursor solution increases,
the conductivity, K decreases, which results in an increase
in the diameter of the droplet, Dd, and an increase in the
electrostatic jet nanoparticles increased as the PVAc con-
tent increased, and lead to an increase in the mechani-
cal strength of the droplet shell, as well as a reduction
in the rate of TBA evaporation. Higher PVAc contents in
the precursor solution tended to suppress the formation of
the erythrocyte-like structure of the nanoparticles. Inter-
estingly, however, spherical nanoparticles with a smooth
surface were obtained when the PVAc content of the pre-
diameter of the composite nanoparticles (Fig. 1).
Delivered by Ingenta to: Deakin University Library
IP: 191.101.54.140 On: Sun, 07 Aug 2016 08:38:01
cursor solution was 3 wt%, likely because the droplets size
Solidified shell formed because of the rapid evapo-
Copyright: American Scientific Publishers
was small, whereas the surface tension of the precursor
solution was relatively large (Fig. 2).
ration of TBA from the surface and the inside of the
droplet following the electrostatic jet process. The TBA
inside the droplet then diffused from the center to the
surface because to the resulting concentration gradient.
The rates of the contraction and evaporation processes
were different because of the fast evaporation of TBA and
the slow migration of the polymer. The erythrocyte-like
butyl titanate/PVAc composite nanoparticles were finally
obtained when a large pore formed on the surface of
nanoparticles. This phenomenon was related to the diam-
eter of the droplets and the PVAc content of the precur-
sor solution. The diffusion distance of the TBA and PVAc
decreased with decreasing droplet size, which made it dif-
ficult to form large pores using this process. Furthermore,
the thickness of the solidified shell on the surface of the
Figure 3 shows the result for the thermal gravimet-
ric analysis of the butyl titanate/PVAc nanoparticles fab-
ricated using precursor solution containing 3 wt% PVAc.
Increasing the calcinations temperature led to a decrease
in the weight of the nanoparticles. At the beginning of the
ꢀ
thermal gravimetric analysis process (< 200 C), weight
losses from the nanoparticles were attributed to the evap-
oration of adsorbed water and residual solvent. Decompo-
sition of the PVAc occurred over a temperature range of
(a)
(b)
Figure 6. TEM images of TiO2 nanoparticles. (a) Multi-pores,
Figure 7. Average diameters of the TiO2 nanoparticles made using pre-
(b) single-pore.
cursor solutions with different PVAc contents.
J. Nanosci. Nanotechnol. 16, 9943–9950, 2016
9947

Fabrication of TiO2 Nanoparticles by Electrostatic Jet Using the Low Dielectric Constant Solvent
Tang et al.
Figure 9. Methylene blue degradation rates photocatalyzed by TiO2
Figure 8. Methylene blue degradation rates photocatalyzed by TiO2
nanoparticles with different contents.
nanoparticles with different diameters.
ꢀ
surface morphology obviously. Furthermore, in compari-
son with Figure 2, a mixture of nanoparticles and short
fibers was obtained when the PVAc content of the precur-
sor solution was greater than 9 wt%, because the different
shrinkage rates of the fibers and nanoparticles during the
calcination process lead to the breakage of the fibers.
Figure 7 shows the average diameters of the TiO2
nanoparticles at different PVAc contents. As shown in the
figure, the diameter of the TiO2 nanoparticles increased
as the PVAc content increased from 623ꢅ8 122ꢅ8 to
1328ꢅ3 247ꢅ6 nm, to give a wide diameter distribution,
200–300 C and the butyl titanate has converted to TiO2
when the calcination temperature exceeded 450 ꢀC. On the
basis of these results, a calcination temperature of 500 C
was selected because this did not result in any changes to
weight of the nanoparticles.
Figure 4 shows the XRD patterns of the butyl
titanate/PVAc nanoparticles that had been calcined at dif-
ferent temperatures. No peaks appeared in the case of the
composite nanoparticles because they were amorphous in
nature. All of the peaks observed in the XRD patternsꢀof
the TiO2 nanoparticles calcined at 500, 550 and 600 C
were consistent with those in the JCPDS pattern 89-4921
(Anatase TiO2ꢃ.30 The diffraction peaks were narrower and
ꢀ
Delivered by Ingenta to: Deakin University Library
which could be used to improve the packing density of the
IP: 191.101.54.140 On: Sun, 07 Aug 2016 08:38:01
TiO2 nanoparticles.
Copyright: American Scientific Publishers
Figure 8 compares the degradation rates of methylene
sharper ꢀin the TiO2 nanoparticles that had been calcined
ꢀ
blue that were photocatalyzed by the TiO2 nanoparticles
with different diameters (The nanoparticles were made by
different PVAc content). After 40 min of UV light expo-
sure, degradation rates of methylene blue were decreased
from 92.39% to 60.11% with the average diameter of TiO2
nanoparticles range 623.8 nm to 1328.3 nm (The PVAc
content of solutions range 1 wt% to 11 wt%). Smaller
diameters of TiO2 nanoparticles lead to higher its specific
surface area. As shown in Table III, the surface area of the
TiO2 nanoparticles made using precursor solutions with
1 wt% PVAc contents is 23.375 m2/g, and the average
at 550 C than those that had been calcined at 500 C.
In contrast, the anatase TiO2 calcined at 600 ꢀC was partly
converted into rutile TiO2. As expected, the calcinations
of the butyl titanate/PVAc nanoparticles at 550 ꢀC did not
affect the phase content of the anatase TiO2 nanoparticles.
Figure 5 shows the morphologies of the TiO2 nanopar-
ticles calcined at 550 ꢀC from the precursor solutions con-
taining different PVAc contents. Form the above SEM
images it was clear that erythrocyte-like TiO2 nanoparti-
cles were formed from the butyl titanate/PVAc nanopar-
ticles, except for the spherical nanoparticles with smooth
surfaces that were formed when the PVAc content was
3 wt%. The erythrocyte-like structure of the TiO2 nanopar-
ticles (PVAc content was 1 wt%) was investigated by
TEM, as shown in Figure 6. The TEM images of the
resulting TiO2 nanoparticles revealed that their surfaces
were porous and that they possessed an erythrocyte-like
Table III. Physical properties deduced from N2 adsorption at 77 K on
TiO2 nanoparticles made using precursor solutions with 1 wt% PVAc
contents.
Physical properties
Value
Surface area (m2/g)
23ꢅ375
0ꢅ083
15ꢅ970
Average pore volume (cm3/g)
Average pore diameter (nm)
Figure 10. GCMS data of intermediate degradation products of methy-
lene blue.
9948
J. Nanosci. Nanotechnol. 16, 9943–9950, 2016

Tang et al.
Fabrication of TiO2 Nanoparticles by Electrostatic Jet Using the Low Dielectric Constant Solvent
ꢀ
Table IV. Determination of inorganic ions in the methylene blue solu-
tion after 40 min of treatment.
TiO2 nanoparticles was 550 C. The different morpholo-
gies of the TiO2 nanoparticles formed in the current study
could be applied in different fields, such as photocatalysis
and solar cells for the erythrocyte-like TiO2 nanoparticles
because of their large surface area, and lithium ion batter-
ies for the nanoparticle and fiber mixtures because of their
high bulk density. Specifically, the 40 min degradation rate
of methylene blue catalyzed by titanium oxide nanoparti-
cles when diameter is 238 nm and adding content is 2 g/L
is 92.39%, which is advantageous for photodegradation of
organic pollutants in wastewater.
Inorganic ions
Cl−
NO3−
1.602
SO24−
0.678
Concentration/mg·L−1
1.458
pore diameter is 15.970 nm. The larger specific surface
area because of the erythrocyte-like structures would also
increase the photocatalytic activity, because more organics
can be adsorbed. Meanwhile, the suspensions were stirred
magnetically under dark conditions (without UV light) or
no adding the TiO2 nanoparticles for 40 min. Simultane-
ously, degradation is also occurred by the absorption of
TiO2 nanoparticles and degradation of UV light.
Figure 9 shows the influences of TiO2 nanoparticles
contents on its degradation rates, the average diameter of
nanoparticles is 623.8 nm. As the content of TiO2 nanopar-
ticles increased, the degradation rates are increased first
and then declines. 92.39% of the methylene blue was
dissociated by adding 2 g/L TiO2 nanoparticles. Though
the effective reaction area is increased by adding content
of TiO2 nanoparticles, the utilization of the UV light is
decreased when added excessive nanoparticles since the
UV light is blocked.
Acknowledgments: The authors would like to
acknowledge the support from the National Natural
Science Foundation of China (No. 51202188) and
the Natural Science Foundation of Shaanxi Province
(No. 2012JZ6001).
References and Notes
1. P. F. Lee, X. Zhang, D. D. Sun, J. Du, and J. O. Leckie, Colloids
Surf. A 324, 202 (2008).
2. J. Wang, Y. Zhou, and Z. Shao, Electrochim. Acta 97, 386 (2013).
3. J. Xie, D. Jiang, M. Chen, D. Li, J. Zhu, X. Lü, and C. Yan, Colloids
Surf. A 372, 107 (2010).
4. L. Tu, H. Pan, H. Xie, A. Yu, M. Xu, Q. Chai, Y. Cui, and X. Zhou,
Solid State Sci. 14, 616 (2012).
After treating for 40 min, the methylene blue solution
was analyzed by GCMS and chromatographer, and results
are shown in Figure 10 and Table IV. Based on the inter-
mediate and final products detected, Cl− is first ionized
5. J. Liu, G. Zhang, W. Ao, K. Yang, S. Peng, and C. Müller-Goymann,
Appl. Surf. Sci. 258, 8083 (2012).
Delivered by Ingenta to: Deakin University Library
6. Y. Mitsunori, G. Yuya, M. Uota, T. Torikai, and T. Watari, J. Eur.
IP: 191.101.54.140 On: Sun, 07 Aug 2016 08:38:01
Ceram Soc. 26, 673 (2006).
and exists in the detached state during the dissolution
Copyright: American Scientific Publishers
7. Y. Han, G. Li, and Z. Zhang, J. Cryst. Growth 295, 50 (2006).
of the methylene blue molecule.31. C-S and C-N are the
most active parts of the remaining structure of the methy-
lene blue molecule and the two bonds are broken more
easily. Then N-(2-Naphthy)aniline and 1-Cyclohexy1-3-
ethoxy-butan-2-one determined during the GCMS analy-
sis are formed. These oxidize organic molecular structures
until they are finally transformed into inorganic ions, such
8. J. Yang, X. Zhang, C. Wang, P. Sun, L. Wang, B. Xia, and Y. Liu,
Solid State Sci. 14, 139 (2012).
9. Y. Terada, Y. Suzuki, and S. Tohn, Mater. Res. Bull. 47, 889
(2012).
10. K. Starbova, D. Petrov, N. Starbov, and V. Lovchinov, Ceram Int.
38, 4645 (2012).
11. L. Zhang, Y. G. Li, H. Y. Xie, H. Z. Wang, and Q. H. Zhang,
J. Nanosci. Nanotechnol. 15, 2944 (2015).
12. Y. I. Lee, J. S. Lee, E. S. Park, D. H. Jang, J. E. Lee, K. Kim,
N. V. Myung, and Y. H. Choa, J. Nanosci. Nanotechnol. 14, 8005
(2014).
13. J. G. Zhao, Y. M. Wu, Z. J. Liu, W. Y. Zhang, S. J. Liu, Z. L. Liu,
and B. A. Lu, Nanosci. Nanotechnol. Lett. 6, 717 (2014).
14. X. Zeng, Y. Ou, Y. Yang, C. Xian, and S. H. Xie, Nanosci. Nano-
technol. Lett. 6, 1075 (2014).
as CO2, H2O, Cl−, SO42−, and NO3−. The ions SO24−
,
NO3−, and Cl− were found, indicating that methylene blue
molecules oxidize into SO24−, NO3−, and Cl− during the
degradation process.
15. O. Solcova, T. Balkan, Z. Guler, M. Morozova, P. Dytrych, and A. S.
Sarac, Sci. Adv. Mater. 6, 2618 (2014).
16. A. Suhendi, A. B. Nandiyanto, M. M. Munir, T. Ogi, and
K. Okuyama, Mater. Lett. 106, 432 (2013).
17. L. Thirugnanam, S. Kaveri, M. Dutta, N. V. Jaya, and N. Fukata,
J. Nanosci. Nanotechnol. 14, 3034 (2014).
18. P. F. Du, L. X. Song, and J. Xiong, J. Nanosci. Nanotechnol.
14, 4164 (2014).
19. D. Y. Lee, J. T. Kim, Y. S. Song, and B. Y. Kim, J. Nanosci. Nano-
technol. 15, 566 (2015).
20. Q. Zhang, J. Liu, X. Wang, M. Li, and J. Yang, Colloid Polym. Sci.
288, 1385 (2010).
21. Y. Wu and R. L. Clark, J. Colloid Int. Sci. 310, 529 (2007).
22. J. Zheng, A. He, J. Li, J. Xu, and C. C. Han Polymer 47, 7095
(2006).
23. P. B. Elliott, G. J. Leslie, and P. H. Paul, J. Am. Chem. Soc. 73, 373
(1951).
4. CONCLUSIONS
In summary, we have prepared PVAc/butyl titanate com-
posite nanoparticles by electrostatic jet using TBA as sol-
vent, because of its low dielectric constant, high volatility
and suitable surface tension properties. When the PVAc
content was 3 wt%, the resulting composite nanoparticles
possessed a smooth surface and perfect spherical struc-
tures, whereas when the PVAc content was 9 wt% or
more, mixture composed of nanoparticles and fibers were
observed, and other were erythrocyte-liked in shape and
contained large pits on their surface. Following calcina-
tion, TiO2 nanoparticles with a diameter in the range of
623ꢅ8 122ꢅ8 to 1328ꢅ3 247ꢅ6 nm were obtained. XRD
results showed the calcination temperature of the anatase
J. Nanosci. Nanotechnol. 16, 9943–9950, 2016
9949

Fabrication of TiO2 Nanoparticles by Electrostatic Jet Using the Low Dielectric Constant Solvent
Tang et al.
24. J. Y. Park, I. H. Lee, and G. N. Bea, J. Ind. Eng. Chem. 14, 707
28. S. Agarwal, A. Greiner, and J. H. Wendorff, Adv. Funct. Mater.
(2008).
19, 2863 (2009).
25. M. Lambla, J. Druz, and A. Bouilloux, Polym. Eng. Sci. 27, 1221
(1987).
29. J. Rosell-Llompart and J. F. Mora, J. Aerosol. Sci. 25, 1093
(1994).
26. B. Ding, C. K. Kim, H. Y. Kim, M. K. Seo, and S. J. Park, Fiber
polym. 5, 105 (2004).
27. S. A. Theron, E. Zussman, and A. L. Yarin, Polymer 45, 2017 (2004).
30. Q. Zhang and L. Gao, J. Eur. Ceram. Soc. 26, 1535 (2006).
31. F. Huang, L. Chen, H. Wang, and Z. Yan, Chem. Engin. J. 162, 250
(2010).
Received: 24 December 2014. Accepted: 24 July 2015.
Delivered by Ingenta to: Deakin University Library
IP: 191.101.54.140 On: Sun, 07 Aug 2016 08:38:01
Copyright: American Scientific Publishers
9950
J. Nanosci. Nanotechnol. 16, 9943–9950, 2016