Facile preparation of sphere-like copper ferrite nanostructures and their enhanced visible-light-induced photocatalytic conversion of benzene

Article abstract of DOI:10.1016/j.materresbull.2013.06.063

Spinel copper ferrite nanospheres with diameters of about 116 nm were synthesized in high yield via a facile solvothermal route. The prepared nanospheres had cubic spinel structure and exhibited good size uniformity and regularity. The band-gap energy of CuFe₂O₄ nanospheres was calculated to be about 1.69 eV, indicating their potential visible-light- induced photocatalytic activity. The dramatically enhanced photocatalytic activity of the CuFe₂O₄ nanospheres was evaluated via the photocatalytic conversion of benzene under Xe lamp irradiation. By using the in situ FTIR technique, ethyl acetate, carboxylic acid and aldehyde could be regarded as the intermediate products, and CO₂ was produced as the final product during the reaction process. This study provided new insight into the design and preparation of functional nanomaterials with sphere structure in high yield, and the as-grown architectures demonstrated an excellent ability to remove organic pollutants in the atmosphere.

Full text of DOI:10.1016/j.materresbull.2013.06.063

Materials Research Bulletin 48 (2013) 4216–4222
Contents lists available at SciVerse ScienceDirect
Materials Research Bulletin
journal homepage: www.elsevier.com/locate/matresbu
Facile preparation of sphere-like copper ferrite nanostructures and
their enhanced visible-light-induced photocatalytic conversion of
benzene
a
a
a
b
b
b
Yu Shen a,b, , Yanbo Wu , Hongfeng Xu , Jie Fu , Xinyong Li , Qidong Zhao , Yang Hou
*
a School of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028, China
b Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and
Technology, Dalian University of Technology, Dalian 116024, China
A R T I C L E I N F O
A B S T R A C T
Article history:
Spinel copper ferrite nanospheres with diameters of about 116 nm were synthesized in high yield via a
facile solvothermal route. The prepared nanospheres had cubic spinel structure and exhibited good size
uniformity and regularity. The band-gap energy of CuFe2O4 nanospheres was calculated to be about
1.69 eV, indicating their potential visible-light-induced photocatalytic activity. The dramatically
enhanced photocatalytic activity of the CuFe2O4 nanospheres was evaluated via the photocatalytic
conversion of benzene under Xe lamp irradiation. By using the in situ FTIR technique, ethyl acetate,
carboxylic acid and aldehyde could be regarded as the intermediate products, and CO2 was produced as
the final product during the reaction process. This study provided new insight into the design and
preparation of functional nanomaterials with sphere structure in high yield, and the as-grown
architectures demonstrated an excellent ability to remove organic pollutants in the atmosphere.
ß 2013 Elsevier Ltd. All rights reserved.
Received 15 December 2012
Received in revised form 23 June 2013
Accepted 25 June 2013
Available online 9 July 2013
Keywords:
A. Nanostructures
B. Chemical synthesis
C. Infrared spectroscopy
D. Catalytic properties.
1. Introduction
effects on catalytic hydrogen production from dimethyl ether over
CuFe2O4 spinel-based composites [7].
Because of their attractive magnetic, electronic, thermal and
catalytic properties, copper ferrites (CuFe2O4) have been widely
investigated and used in variety of applications such as magnetic
material [1,2], anode material [3], catalyst [2,4], and so on.
Especially CuFe2O4 nanoparticles have long played an important
role in various catalytic applications including thermal catalysis,
photocatalytic degradation of pollutants and photocatalytic
hydrogen production. Khedr et al. investigated the kinetics and
mechanisms of CO2 catalytic decomposition over freshly reduced
nano-crystallite CuFe2O4 [4]. Nasrallah et al. fabricated the novel
hetero-system CuFe2O4/CdS and studied its photocatalytic reduc-
tion of Cr(VI) [5]. Yang et al. reported photocatalytic activity
evaluation of tetragonal CuFe2O4 nanoparticles for the H2
evolution under visible light irradiation [6]. Faungnawakij and
coworkers investigated the hydrogen reduction and metal dopant
Benzene is widely used as a solvent in industrial processes and is
also one of the most abundant volatile aromatic hydrocarbons found
in urban atmospheres. Many approachs were developed to remove
benzene from the polluted environment because of its severe toxic
effects on the human body [8]. Xu and coworkers reported the
photocatalytic degradation of benzene using a carbon nanotubes
(CNT)/TiO2 nanocomposite photocatalyst prepared by a simple
impregnationmethod[9]. Huang etal. synthesizeda nanostructured
Cd2Ge2O6 photocatalyst, which showed enhanced photocatalytic
activity for environmental purification of benzene in air [10]. Xue
et al. obtained nanocrystalline Sr2Sb2O7 via a facile hydrothermal
method and found its high photocatalytic activity for benzene
degradation [11]. The kinetic process of benzene photocatalytic
degradation over visible-light-driven silver vanadates photocata-
lysts was investigated by Chen et al. [12]. Up to now, there are few
reports about the photocatalytic conversion of benzene on sphere-
like copper ferrite nanostructures irradiated with visible-light. In
addition, as for the photocatalytic oxidation of benzene vapor, the
reaction intermediates on the photocatalytic surfaces were often
characterized through solvent extraction after the photoprocess
[13], it may not reveal the real adsorbates formed on the surface of
photocatalysts during the photoreactions. Therefore in the present
study, visible-light-induced photocatalytic conversion of benzene
* Corresponding author at: School of Environmental and Chemical Engineering,
Dalian Jiaotong University, Dalian 116028, China. Tel.: +86 411 8410 6746;
fax: +86 411 8410 6890.
E-mail addresses: shenyuqing0322@gmail.com, shenyuqing5109@hotmail.com
(Y. Shen).
0025-5408/$ – see front matter ß 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.materresbull.2013.06.063

Y. Shen et al. / Materials Research Bulletin 48 (2013) 4216–4222
4217
over CuFe2O4 nanospheres was investigated using ‘‘in situ’’
measurements of infrared spectroscopy.
transform infrared (FTIR, BRUKER VERTEX 70) spectrum was
recorded in the range 4000–450 cmÀ1 with 4 cmÀ1 resolution. The
light absorption property was measured using UV–Vis absorption
spectrophotometer (JASCO, UV-550) with a wavelength range of
200–800 nm. Thermogravimetric and differential thermal analysis
(TG/DTA, Seiko SII 6300) were performed at a heating rate of 10 8C/
min under air atmosphere.
2. Experimental details
2.1. Preparation of materials
2.1.1. CuFe2O4 nanospheres
2.3. Photocatalytic activity evaluation
All chemicals in this work were analytical grade reagents and
used as starting materials without further purification.
Cu(NO3)2Á3H2O (5 mmol, 1.208 g) and Fe(NO3)3Á9H2O (10 mmol,
4.040 g) were dissolved in ethylene glycol (80 mL) to form a clear
solution, followed by the addition of NaAc (7.2 g) and polyethylene
glycol (2.0 g). The mixture was stirred vigorously for 90 min and
then sealed in a Teflon lined stainless-steel autoclave (100 mL). The
autoclave was heated and maintained at 200 8C for 22 h, and
allowed to cool to room temperature. Subsequently, the black
precipitates were collected and washed with ethanol followed by
drying at 60 8C for 6 h. For the heat treatment, the samples were
Photocatalytic activities of the catalysts were determined using
the photocatalytic conversion of benzene under visible-light
irradiation in a self-made in situ quartz IR photoreaction cell.
The cell (diameter, 4 cm; length, 10 cm) consisted of two NaCl
windows and a sample holder (diameter, 13 mm) for the catalyst
wafer (0.05 g). After the catalyst was placed in the sample holder, a
small amount of benzene was injected into the reactor with a
microsyringe. The benzene vapor was allowed to reach adsorption
equilibrium in the reactor prior to irradiation. The analysis of the
benzene concentration in the reactor was conducted with a GC-FID
(Agilent 7890A). The initial concentration of benzene after
adsorption equilibrium was controlled at about 280 mg/m3. The
annealed at 650 8C for 2 h with a heating rate of 2 8C minÀ1
.
2.1.2. CuFe2O4 nanoparticles
Xenon lamp (XQ-500 W) (l > 400 nm) with the light intensity of
The CuFe2O4 nanoparticles were prepared according to the
reference [6]. The typical procedures are as follows: Cu(CH3-
COO)2ÁH2O (5 mmol, 0.998 g) and Fe(NO3)3Á9H2O (10 mmol,
4.040 g) were dissolved together in 100 mL distilled deionized
water to produce a clear solution. Then NH3ÁH2O (28%) was added
into the solution drop by drop under vigorous stirring until the pH
became around 9, and viscous precipitates were produced. The
precipitates were then dried at 80 8C by using a water bath, and
subsequently calcined at 850 8C for 3 h with a heating rate of 10 8C
about 50 mW cmÀ2 was turned on to allow the photocatalytic
reaction to proceed under batch conditions. The IR spectra were
continuously collected on the VERTEX 70-FTIR with a resolution of
1 cmÀ1 and 20 scans in the region of 4000–600 cmÀ1 during the
course of reaction. Scheme 1 showed the schematic illustration of
the photocatalytic reaction setup.
3. Results and discussion
minÀ1
.
3.1. XRD analysis
2.2. Characterization
The phases of the synthesized nano-sphere-like CuFe2O4 and
CuFe2O4 nanoparticles are identified by XRD characterization
(Fig. 1). The diffraction peaks of the CuFe2O4 nanospheres are in
good agreement with the standard diffraction pattern of the spinel
CuFe2O4 (JCPDS 25-0283). Obviously, all the diffraction peaks can
be indexed to (1 1 1), (2 2 0), (3 1 1), (2 2 2), (4 0 0), (5 1 1) and
(4 4 0) crystallographic planes. The lack of diffraction peaks from
impurities suggests the high phase purity of nano-sphere-like
CuFe2O4. However the diffraction peaks of CuFe2O4 nanoparticles
prepared using co-precipitation method can be readily indexed to
tetragonal-type CuFe2O4 (JCPDS 34-0425).
The crystal structure of the CuFe2O4 nanospheres and
nanoparticles was examined by X-ray diffraction (XRD, Rigaku
D/max) with Cu Ka radiation (l = 0.15418 nm). The morphology of
the prepared samples was characterized by scanning electron
microscopy (SEM, JSM-5600 LV) and transmission electron
microscopy (TEM, Hitachi 800 system at 200 kV). Energy disper-
sive X-ray analysis (EDX, Horiba 7593 H) was performed to
determine the elemental concentration distribution on the sample.
X-ray photoelectron spectroscopy (XPS, PHI 5600 mode) was
performed to examine the surface properties and composition of
the samples. All the binding energies were calibrated by using the
contaminant carbon (C 1s) 284.6 eV as a reference. Fourier
The average crystallite sizes of nano-sphere-like CuFe2O4 are
determined from the broadening of the peak corresponding to the
Scheme 1. Schematic illustration of the photocatalytic reactor system setup.

4218
Y. Shen et al. / Materials Research Bulletin 48 (2013) 4216–4222
nanospheres to be 116 nm with a standard deviation of 26 nm
(inset of Fig. 2a). It is believed that the convenient synthesis route
reported here would provide an opportunity for easy and large-
scale production of the CuFe2O4 nanospheres. It can be observed
from the high-magnification SEM images (Fig. 2b and c) that the
CuFe2O4 nanospheres exhibited relatively rough surfaces com-
posed of smaller particles. Meanwhile, the EDX spectrum, shown in
Fig. 2d, indicates that the CuFe2O4 nanospheres are mostly
composed of Cu, Fe and O elements.
3.3. TEM analysis
The morphology of the nanospheres is further investigated by
TEM. Fig. 3a shows the TEM image of the CuFe2O4 nanospheres,
exhibiting some of the spheres with sizes of 100–145 nm and the
primary particle sizes were about 10–20 nm. The SAED pattern
taken from a single isolated nanosphere shows clear diffraction
spots, indicating a good single-crystal structure (Fig. 3b). Further-
more, The interplanar spacings of the parallel fringes in the HRTEM
images (Fig. 3c and d) were 0.479 nm, 0.296 nm and 0.252 nm,
which agree well with the (1 1 1), (2 2 0) and (3 1 1) planes of the
CuFe2O4 nanospheres, respectively. These results are in good
agreement with the XRD and SEM analysis.
Fig. 1. XRD patterns of the CuFe2O4 nanospheres and CuFe2O4 nanoparticles.
(3 1 1) diffraction, using Scherrer’s formula: D = K
is the average crystallite size (nm), is the x-ray wavelength and K
is Scherrer’s constant (K = 0.89). B is the full width at half
maximum observed in radians and is the angle of diffraction.
l/B cosu, where D
l
u
The predicted crystallite sizes of nano-sphere-like CuFe2O4 is
about 16.21 nm. Similarly, the average crystal sizes of the CuFe2O4
nanoparticles calculated by Scherrer’s formula is about 19.11 nm
from the peak to the (2 1 1) diffraction.
3.4. XPS analysis
The chemical composition of the CuFe2O4 nanospheres was
further investigated using XPS. The XPS survey spectrum in
Fig. 4a reveals that elements Cu, Fe, O, and adventitious C
existed in the nanospheres. As shown in the spectrum in Fig. 4b,
the peaks corresponding to Cu 2p1/2 and Cu 2p3/2 are detected at
953.0 and 933.0 eV with the intense satellite at about 940 eV.
These should be assignable to the characteristic peaks for Cu2+
species [14]. Fig. 4c shows the Fe 2p peaks at the binding
energies of 723.1 and 709.9 eV, which is consistent with that
reported for Fe3+ in the sample [15]. The XPS spectrum of the O
3.2. SEM analysis
Fig. 2a presents a low-magnification SEM image of nano-
sphere-like CuFe2O4, showing that the as-prepared sample
consisted of many smaller spheres. The size distribution of the
CuFe2O4 nanospheres is estimated from the SEM imaging analysis
of at least 200 particles. The histogram of the particle size
distribution shows the average particle size of the CuFe2O4
Fig. 2. SEM images of the CuFe2O4 nanospheres with different magnifications (a–c). Inset: Histograms representing the size distribution of the CuFe2O4 nanospheres. (d) EDX
spectrum of the corresponding sample.

Y. Shen et al. / Materials Research Bulletin 48 (2013) 4216–4222
4219
Fig. 3. TEM image (a), SAED pattern (b), and the magnified HRTEM (c, d) of the CuFe2O4 nanospheres.
1s region is also detected, as shown in Fig. 4d. The O 1s peak
is found to be asymmetric, suggesting that at least two kinds of
oxygen species are present in the near surface region. The peak
for O1s in the sample may devolve into two small peaks. The
peak located at 528.7 eV is attributed to the O in CuFe2O4,
while the peak located at 530.2 eV is assigned to the
adsorbed oxygen [16]. By combining the EDX and XRD analysis,
it can be confidently confirmed that the CuFe2O4 nanospheres
were successfully synthesized by the facile solvothermal
route.
Fig. 4. XPS spectra of the CuFe2O4 nanospheres, (a) survey of the sample, (b) Cu 2p, (c) Fe 2p and (d) O 1s.

4220
Y. Shen et al. / Materials Research Bulletin 48 (2013) 4216–4222
3.5. FTIR analysis
The FTIR spectrum of the CuFe2O4 nanospheres in the range
4000–450 cmÀ1 is shown in Fig. 5. From the lower line, the
strongest characteristic peaks of spinel metal oxides at 579 and
476 cmÀ1 are assigned to the metal-oxygen bonds in the unused
fresh material [17]. Moreover, the frequency bands at 1632 and
3442 cmÀ1 are ascribed to the adsorbed water molecules and the
surface hydroxyl, respectively [18], which can receive photo-
induced holes to produce active radicals for catalytic reactions. The
band at 2360 cmÀ1 corresponds to adsorbed or atmospheric CO2
[19]. In addition, the peaks at 2925 and 2846 cmÀ1 may be
attributed to
n (C–H) of remnant trace polyethylene glycol [20,21].
2
Fig. 6. UV–Vis absorption spectrum and plot of (ahn) versus photon energy (hn)
(Inset) for the CuFe2O4 nanospheres.
3.6. Photo-absorbance property
The optical property of the CuFe2O4 nanospheres is investigated
by UV–Vis absorption spectroscopy. As shown in Fig. 6, the catalyst
shows strong photo absorption in the UV and visible spectral
region. This absorption should be attributed to the direct band
absorption of CuFe2O4. The band-gap can be estimated according
as soft templates for the formation of the nanosphere structure of
CuFe2O4.
to the energy dependence relation of
a
hn
= (hn
ÀEg)1/2, where
a
3.8. Photocatalytic conversion of benzene
and Eg are the absorption coefficient and the energy gap of a
2
semiconductor, respectively. The plot of (
a
hn)
versus photo
Fig. 8 shows FTIR spectra variation curves of benzene on the
CuFe2O4 nanospheres under visible light irradiation, recorded as
the function of irradiation time. The characteristic peaks of
benzene in infrared spectra are as follows: the bands at 3089,
3055, and 3047 cmÀ1 (Fig. 8a) are assigned to the C–H stretching
mode in the benzene rings [27], the vibrational bands at 1964,
1948, 1820, and 1802 cmÀ1 (Fig. 8c) are assigned to the C–H out-of-
plane bending mode [28], the 1485 cmÀ1 band is related to C55C
stretching vibrations, and the bands in the range of 1020–
1050 cmÀ1 (Fig. 8d) could be ascribed to C–H in-plane deformation
vibrations [29]. In addition, the bands at 2360 and 2340 cmÀ1
(Fig. 8c) are attributed to CO2 It can be found that the increase of
the irradiation time caused significant decrease in the intensity of
characteristic peaks of benzene (Fig. 8a, c and d) and great increase
of the ones corresponding to CO2 (Fig. 8b).
Furthermore, some new surface species also formed during the
reaction, as evidenced by the FTIR spectra (Fig. 8d). New bands at
1108 cmÀ1 are attributed to C–O stretching vibration which
existed in ester [30]. The 948 cmÀ1 band is assigned to O–H
out-of-plane deformation vibration of carboxylic acid [31] and
792 cmÀ1 band is assigned to C–H deformation vibration of
aldehyde [32]. On the basis of the previous report [13] and our
results, ethyl acetate, carboxylic acid and aldehyde are the
intermediate products during the photocatalytic degradation of
benzene, CO2 is produced as the final product. Based on the
intermediate products identified, the photocatalytic oxidation
mechanism of benzene was speculated and depicted in Fig. 9.
energy (h ) of the sample can be fitted into a line [21,22]. The band-
n
gap energy of the CuFe2O4 nanospheres is calculated to be about
1.69 eV from the intercept of the tangent to the line, indicating that
the CuFe2O4 nanospheres may have visible-light photoactivity.
3.7. TG and DTA
Thermal properties of the CuFe2O4 nanospheres before
calcination are evaluated by TG and DTA. Test conditions are
started from 20 to 1100 8C at a rate of 10 8C/min under air
atmosphere. The TG/DTA curves of the CuFe2O4 nanospheres are
shown in Fig. 7. It can be seen that the DTA plot presents an
endothermic peak at 287 8C, which corresponds to the thermal
decomposition of PEG [23]. The first weight loss on the TG curve in
the temperature range from 20 to 330 8C is attributed to the
evaporation and decomposition of the solvents. The second and
third weight loss occur in the range from 330 to 630 8C and 630 to
1100 8C, which correspond to the combustion of residual carbon
[24,25], and crystal transformation of CuFe2O4, respectively [26].
The small exothermic peak at about 620 8C on DTA curve
corresponds to the combustion temperature of residual carbon.
The TG/DTA analysis shows that there existed some amounts of
PEG molecules in the CuFe2O4 nanospheres that could not be
completely removed by washing. PEG molecules interacted with
the reactants, forming the composite globules [23], which behaved
Fig. 5. FTIR spectrum of the CuFe2O4 nanospheres.
Fig. 7. TG and DTA curves of the CuFe2O4 nanospheres obtained before calcination.

Y. Shen et al. / Materials Research Bulletin 48 (2013) 4216–4222
4221
Fig. 8. FTIR spectra recorded as a function of irradiation time following the photocatalytic conversion of benzene on the CuFe2O4 nanospheres: (a) infrared spectra in the
region 3300–2800 cmÀ1; (b) infrared spectra in the region 2500–2200 cmÀ1, (c) infrared spectra in the region 2200–1300 cmÀ1; (d) infrared spectra in the region 1200–
750 cmÀ1
.
Fig. 10 illustrates the photocatalytic activity of CuFe2O4
nanospheres as compared with CuFe2O4 nanoparticles. Benzene
could not be degraded in a direct photolytic process without any
photocatalyst under Xe lamp irradiation. The photocatalytic
conversion of benzene was 29.6% on the CuFe2O4 nanoparticles
photocatalyst. However, benzene conversion increased to 44.8%
when the CuFe2O4 nanospheres were used as catalysts under the
same light conditions, indicating their enhanced visible-light-
induced photocatalytic activity over degradation of gas pollutants.
The photocatalytic conversion rate of benzene over Bi2WO6@C
microspheres was 42.6% [33], which was similar to that of CuFe2O4
nanospheres. Nanomaterials with sphere structure show a lower
density, higher surface area and distinct optical property [34–36].
These advantages permit photocatalysts the high contact area with
the pollutants and enable photocatalytic reactions to occur faster.
But nanomaterials may be more difficult to synthesize and their
dimensions and morphology may be difficult to control.
Moreover the photocatalytic stability of the investigated
nanospheres can be proved by the FTIR spectra of nanospheres
before and after photocatalytic reaction for 8 h. As shown in Fig. 5,
Fig. 9. The mechanism of the photocatalytic conversion of benzene over the CuFe2O4 nanospheres.

4222
Y. Shen et al. / Materials Research Bulletin 48 (2013) 4216–4222
Catalysis of Sichuan (China) Institutes of High Education (No.
LYJ1209).
References
[1] R.K. Selvan, V. Krishnan, C.O. Augustin, H. Bertagnolli, C.S. Kim, A. Gedanken,
Chem. Mater. 20 (2007) 429–439.
[2] H.-M. Fan, J.-B. Yi, Y. Yang, K.-W. Kho, H.-R. Tan, Z.-X. Shen, J. Ding, X.-W. Sun, M.C.
Olivo, Y.-P. Feng, ACS Nano 3 (2009) 2798–2808.
[3] M. Bomio, P. Lavela, J. Tirado, J. Solid State Chem. 12 (2008) 729–737.
[4] M.H. Khedr, A.A. Farghali, Appl. Catal., B 61 (2005) 219–226.
[5] N. Nasrallah, M. Kebir, Z. Koudri, M. Trari, J. Hazard. Mater. 185 (2011) 1398–1404.
[6] H. Yang, J. Yan, Z. Lu, X. Cheng, Y. Tang, J. Alloys Compd. 476 (2009) 715–719.
[7] K. Faungnawakij, R. Kikuchi, N. Shimoda, T. Fukunaga, K. Eguchi, Angew. Chem.
Int. Ed. 47 (2008) 9314–9317.
[8] Q. Lan, L. Zhang, G. Li, R. Vermeulen, R.S. Weinberg, M. Dosemeci, S.M. Rappaport,
M. Shen, B.P. Alter, Y. Wu, W. Kopp, S. Waidyanatha, C. Rabkin, W. Guo, S. Chanock,
R.B. Hayes, M. Linet, S. Kim, S. Yin, N. Rothman, M.T. Smith, Science 306 (2004)
1774–1776.
Fig. 10. Photocatalytic conversion efficiency of benzene over different samples
under visible light irradiation.
[9] Y.-J. Xu, Y. Zhuang, X. Fu, J. Phys. Chem. C 114 (2010) 2669–2676.
[10] J. Huang, K. Ding, X. Wang, X. Fu, Langmuir 25 (2009) 8313–8319.
[11] H. Xue, Z. Li, L. Wu, Z. Ding, X. Wang, X. Fu, J. Phys. Chem. C 112 (2008) 5850–5855.
[12] L.-C. Chen, G.-T. Pan, T.C.K. Yang, T.-W. Chung, C.-M. Huang, J. Hazard. Mater. 178
(2010) 644–651.
the wavenumbers of the characteristic peaks of the fresh (the
lower line) and used (the upper line) materials are almost the
same, except for a little difference in peak intensity.
[13] J. Zhong, J. Wang, L. Tao, M. Gong, L. Zhimin, Y. Chen, J. Hazard. Mater. 139 (2007)
323–331.
[14] K. Faungnawakij, N. Shimoda, T. Fukunaga, R. Kikuchi, K. Eguchi, Appl Catal., B 92
(2009) 341–350.
4. Conclusion
[15] Y.-N. NuLi, Y.-Q. Chu, Q.-Z. Qin, J. Electrochem. Soc. 151 (2004) A1077–A1083.
[16] L. Xue, C. Zhang, H. He, Y. Teraoka, Appl Catal., B 75 (2007) 167–174.
[17] A. Pradeep, P. Priyadharsini, G. Chandrasekaran, J. Magn. Magn. Mater. 320 (2008)
2774–2779.
In conclusion, a facile solvothermal method could be used to
produce spinel CuFe2O4 nanospheres in high yield. The as-
prepared CuFe2O4 nanospheres demonstrated advancement over
CuFe2O4 nanoparticles in photocatalytic conversion of benzene
under Xe lamp irradiation. By using the in situ FTIR technique, ethyl
acetate, carboxylic acid and aldehyde could be regarded as the
intermediate products, and CO2 was produced as the final product
during the reaction process. According to the promising photo-
catalytic ability exhibited in this work, the CuFe2O4 nanospheres
photocatalysts are expected to play an important role in
environmental purification by utilizing solar energy.
[18] X. Song, L. Gao, Langmuir 23 (2007) 11850–11856.
[19] X. Ma, H. Sun, H. He, M. Zheng, Catal. Lett. 119 (2007) 142–147.
[20] L. Chen, H. Dai, Y. Shen, J. Bai, J. Alloys Compd. 491 (2010) L33–L38.
[21] J.A. Glasscock, P.R.F. Barnes, I.C. Plumb, A. Bendavid, P.J. Martin, Thin Solid Films
516 (2008) 1716–1724.
[22] B. Liu, L. Wen, X. Zhao, Sol. Energy Mater. Sol. Cells 92 (2008) 1–10.
[23] Y. Cui, L. Liu, B. Li, X. Zhou, N. Xu, J. Phys. Chem. C 114 (2010) 2434–2439.
[24] S.J. Bu, Z.G. Jin, X.X. Liu, L.R. Yang, Z.J. Cheng, J. Eur. Ceram. Soc. 25 (2005) 673–679.
[25] S. Yu, H. Huang, L. Zhou, Chem. Mater. 19 (2007) 2718–2720.
[26] T. Xu, X. Zhou, Z. Jiang, Q. Kuang, Z. Xie, L. Zheng, Cryst. Growth Des. 9 (2009) 192–
196.
[27] M. Nagao, Y. Suda, Langmuir 5 (1989) 42–47.
[28] N. Sivasankar, S. Vasudevan, J. Phys. Chem. B 108 (2004) 11585–11590.
[29] K.H. Wu, T.C. Chang, Y.T. Wang, Y.S. Hong, T.S. Wu, Eur. Polym. J. 39 (2003) 239–
245.
Acknowledgements
[30] J.B. Kim, J.J. Park, J.H. Jang, Polymer 41 (2000) 149–153.
[31] C.S. Marvel, B.D. Wilson, J. Org. Chem. 23 (1958) 1483–1488.
[32] G. Socrates, Infrared and Raman Characteristic Group Frequencies: Tables and
Charts, third ed., Uxbridge, London, 2004.
[33] Y.L. Chen, X.X. Cao, J.D. Kuang, Z. Chen, J.L. Chen, B.Z. Lin, Catal. Commun. 12
(2010) 247–250.
[34] S.H. Im, U. Jeong, Y.N. Xia, Nat. Mater. 4 (2005) 671–675.
[35] M.J. Li, X. Xu, Y. Tang, Z.N. Guo, H.N. Zhang, H. Zhang, B. Yang, J. Colloid Interface
Sci. 346 (2010) 330–336.
This work was supported financially by the National Nature
Science Foundation of China (No. 21076028 and NSFC-RGC
21061160495), the National High Technology Research and
Development Program of China (863 Program) (No.
2010AA064902), the Major State Basic Research Development
Program of China (973 Program) (No. 2011CB936002), the
Excellent Talents Program of Liaoning Provincial University
(LR2010090) and the Opening Project of Key Laboratory of Green
[36] X.Y. Chen, C. Ma, S.P. Bao, Z. Li, J. Colloid Interface Sci. 346 (2010) 8–11.