Band gap and Schottky barrier engineered photocatalyst with promising solar light activity for water remediation

Article abstract of DOI:10.1039/c5ra24096d

A novel nanophotocatalyst of Mo- and S-doped TiO₂ (Mo,S-codoped TiO₂) was synthesized via a modified sol-gel method in conjunction with photochemical reduction. The XRD results showed that all of the prepared nanocatalysts only contain the anatase phase. The SEM and TEM analyses revealed that the doping of Mo and S does not cause any change in the morphology of the TiO₂ catalyst. Chemical composition analysis carried out using EDX confirmed the successful doping of TiO₂ by Mo and S, and DRS illustrated band gap reduction in TiO₂ after doping. The photocatalytic performance of the samples was tested using the degradation of methyl orange (MO) as a model organic pollutant. The results showed that the photocatalytic activity of the Mo(0.06%), S(0.05%)-codoped TiO₂ catalyst was higher than that of other catalysts under UV and visible light irradiation. Indeed, due to the synergetic effect of doping S and Mo, the Mo,S-codoped TiO₂ catalyst has a higher photoactivity than the pure TiO₂ and TiO₂ doped solely with either Mo or S. Finally, it is proposed that the newly developed Mo,S-codoped TiO₂ photocatalyst could be a great candidate for environmental applications such as air and water purification.

Full text of DOI:10.1039/c5ra24096d

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Band gap and Schottky barrier engineered
photocatalyst with promising solar light activity for
water remediation
Cite this: RSC Adv., 2016, 6, 15678
a
bc
M. Shamshiric and D. Villagrana
*
V. Jabbari, M. Hamadanian,
´
A novel nanophotocatalyst of Mo- and S-doped TiO2 (Mo,S-codoped TiO2) was synthesized via a modified
sol–gel method in conjunction with photochemical reduction. The XRD results showed that all of the
prepared nanocatalysts only contain the anatase phase. The SEM and TEM analyses revealed that the
doping of Mo and S does not cause any change in the morphology of the TiO2 catalyst. Chemical
composition analysis carried out using EDX confirmed the successful doping of TiO2 by Mo and S, and
DRS illustrated band gap reduction in TiO2 after doping. The photocatalytic performance of the samples
was tested using the degradation of methyl orange (MO) as a model organic pollutant. The results
showed that the photocatalytic activity of the Mo(0.06%), S(0.05%)-codoped TiO2 catalyst was higher
than that of other catalysts under UV and visible light irradiation. Indeed, due to the synergetic effect of
doping S and Mo, the Mo,S-codoped TiO2 catalyst has a higher photoactivity than the pure TiO2 and
TiO2 doped solely with either Mo or S. Finally, it is proposed that the newly developed Mo,S-codoped
TiO2 photocatalyst could be a great candidate for environmental applications such as air and water
purification.
Received 14th November 2015
Accepted 26th January 2016
DOI: 10.1039/c5ra24096d
www.rsc.org/advances
the dopant and the conduction band (CB) or valence band (VB)
of TiO2.12 Regarding non-metal doping, Umebayashi et al.13–15
1. Introduction
succeeded in synthesizing S-doped TiO2, which was used as an
efficient visible-light-induced photocatalyst for the photo-
catalytic degradation of methylene blue. They found the
substitution of lattice oxygen in TiO2 by a sulfur anion. Ohno
et al.16–18 found that S atoms could be incorporated as cations
and replace lattice Ti in TiO2. Zhao et al.19 and Majima and
co-workers20 reported that the doping of TiO2 with sulfur can
also reduce its band gap and shi its optical response to the
visible-light region.
In order to further improve the photocatalytic activity, the
codoping of TiO2 with binary non-metals,21–24 a metal and non-
metal,25–28 a metal and metal29,30 and other semiconductors31
has been explored. In this respect, the codoping of TiO2 with
a rare-earth transition metal and non-metallic element has
aroused great interest.32,33 Several studies demonstrated that
codoping with a transition metal and nonmetallic element
could effectively modify the electronic structures of TiO2 and
shi its absorption edge to lower energies.34,35
Due to its resistance to photocorrosion, good physical and
chemical stability, low cost, non-toxicity and strong oxidizing
power, TiO2 is the most widely used photocatalyst in the pho-
todegradation of organic pollutants for air and water purica-
tions.1–5 However, TiO2 has a relatively large band gap (3.20 eV
for anatase TiO2) which enables it to absorb only the UV portion
of solar light (ꢀ5%). Many techniques have been examined for
the extension of the light absorption threshold of TiO2 to the
visible light and near-IR region of solar light such as dye
sensitization,6 transition metals doping,7 noble metal deposi-
tion,8 and anion doping.9,10
Lately, the doping of non-metal elements into TiO2 photo-
catalysts has become a hot research topic, which opens up a new
possibility for the development of solar- or visible light-active
photocatalytic materials. The doping of non-metal ions into
TiO2 can shi its optical absorption edge from the UV to visible
light range.11 This red shi in doped TiO2 was attributed to
the charge-transfer transition between the d-orbital electrons of
The codoping of TiO2 with transition metal and nonmetal
elements has some positive aspects: narrowing the band gap
and inhibition of charge recombination of the photo-generated
electron–hole pairs. In a previous study, it was reported that the
TiO2 absorption spectrum can be extended to the visible light
region by incorporating Cr as a metal and S as a nonmetal into
the TiO2 crystallite.36 The same results were reported for In- and
aDepartment of Chemistry, The University of Texas at El Paso, El Paso, Texas 79968,
USA. E-mail: vahid_jabbari.azeri@yahoo.com
bInstitute of Nanoscience and Nanotechnology, University of Kashan, P.O.Box 87317-
51167, Kashan, Iran. E-mail: hamadani@kashanu.ac.ir; Fax: +98 31 55912397; Tel:
+98 31 55912382
cDepartment of Physical Chemistry, Faculty of Chemistry, University of Kashan,
S-codoped TiO2.37 Ag and
S co-doped TiO2 degraded
Kashan, Iran
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acetaldehyde ten times faster under visible light and 3 times as the sources of visible and UV light, located 40 cm and 25 cm
faster under UV light illuminations compared to that of undo- away from the reactor, respectively. Before light irradiation, the
ped TiO2.38 It was also reported that La and N codoped TiO2 reaction system was stirred in the dark for 30 min to achieve
nanoparticles showed a superior photocatalytic activity for the absorption equilibrium.
degradation of methyl orange under visible light irradiation
compared to solely N-doped or La-doped TiO2.39
2.4. Nanophotocatalyst characterization
The aim of the current study, which to the best of our
The crystalline phases of the prepared samples were analyzed
using an X-ray powder diffractometer (XRD, Bruker D8 Discover
X-ray Diffractometer). The morphology was revealed using
a transmission electron microscope (TEM, Hitachi H-7650) and
scanning electron microscope (SEM, Hitachi S-4800) equipped
with an energy dispersive X-ray detector (EDX). The diffused
reectance spectroscopy (DRS) spectra of the samples were
recorded using a Shimadzu 1800 spectrometer. The UV-Vis
absorption spectra of MO aer the degradation tests were ob-
knowledge is done for the rst time, is to study the synergetic
effect of the codoping of Mo and S on the photocatalytic activity
of a TiO2 photocatalyst. The physico-chemical characteristics of
the prepared catalysts were investigated using XRD, SEM, TEM,
EDX and UV-Vis DRS. Methyl orange (MO) was used as a model
organic pollutant to analyze the photocatalytic performance of
the prepared catalysts. Finally, it was found that Mo,S-codoped
TiO2 has a nanoscale size with strong light absorbance and high
quantum efficiency and the 0.06Mo–0.05S/TiO2 catalyst exhibi-
ted superior photocatalytic activity compared to the bare TiO2
and solely Mo- or S-doped TiO2 photocatalysts under UV and
visible light irradiation.
tained using
a UV-Vis spectrophotometer (Perkin Elmer
Lambda2S, Germany). The Raman spectra of the samples were
collected using a DXR™ Raman Microscope, Thermo Scientic.
2. Experimental
2.1. Chemicals
3. Results and discussion
3.1. Crystalline structure
Ammonium heptamolibdate tetrahydrate ((NH4)6Mo7O24$4H2O),
thiourea, titanium(IV) isopropoxide, glacial acetic acid, ethanol,
and nitric acid were purchased from Merck and were used
without any further purication. Deionized water prepared
using an ultra-pure water system (smart-2-pure made by the
TKA company of Germany) was used throughout.
The X-ray diffraction patterns of the prepared nanocatalysts of
0.05% S/TiO2 with different amounts of Mo doping (0.03, 0.06
and 0.09%) (Fig. 1) and 0.06% Mo with different amounts of S
doping (0.05, 1, 0.15, 0.2 and 0.25%) (Fig. 2) suggested that all
the samples possess high crystallinity with only an anatase TiO2
structure (2q ¼ 25.2, 37.76, 48.02, 54.05, 55.03, 62.80, 68.85,
70.19 and 75.07).36 Furthermore, the XRD patterns did not show
any metal-related phase (as the metallic or metal oxide state)
and it was concluded that the metal ions are uniformly loaded
over the TiO2 surface.
2.2. Synthesis of Mo and S doped TiO2 nanocatalysts
The typical synthesis procedure of pure TiO2 nanoparticles was
described in our previous work.36 The preparation procedure of
S-doped TiO2 nanoparticles was the same as that for pure TiO2,
except the added water contained thiourea as a source of S
(corresponding to 0.05, 0.1, 0.15, 0.2, and 0.25 mol% with
respect to TiO2).37
Fig. 3 illustrates the XRD patterns of pure TiO2 and
Mo(0.06),S(0.05)-codoped TiO2 nanocatalysts. As shown, the
The preparation of Mo,S codoped TiO2 nanoparticles was
carried out via a sol–gel method followed by photochemical
reduction. In this regard, different amounts of (NH4)6Mo7$4H2O
as a Mo precursor (corresponding to 0.03, 0.06 and 0.09 mol%
with respect to TiO2) were added to S-doped TiO2 suspended
in 200 ml of water, followed by purging with N2 for 30 min to
remove oxygen from the suspension. Aerwards, the pot was
tightly capped and put under UV irradiation for 12 h and Mo
nanoclusters were formed and decorated over the S-doped TiO2
nanoparticles.
2.3. Assessment of photocatalytic performance of the
prepared catalysts
The photocatalytic activity of the prepared catalysts was
analyzed using MO degradation under UV and visible light
irradiation. Each time, 0.1 g of photocatalyst was dispersed into
100 ml of 10 ppm MO aqueous solution with a pH of around 2–3
in a quartz reactor (with dimensions of 12 cm ꢁ 5 cm, height
Fig. 1 XRD patterns of the 0.05% S/TiO2 nanocatalysts with (a) 0.03,
(b) 0.06, and (c) 0.09% Mo, prepared via the photochemical deposition
and diameter, respectively). Two 400 W Osram lamps were used method.
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Fig. 4 SEM micrographs of pure TiO2 (A and B) and Mo(0.06),S(0.05)-
codoped TiO2 (C and D).
Fig. 2 XRD patterns of the 0.06% Mo/TiO2 nanocatalysts with (a) 0.05,
(b) 0.1, (c) 0.15, (d) 0.2, and (e) 0.25% S prepared via the sol–gel
method.
Fig. 5 EDX result of the Mo(0.06),S(0.05)-codoped TiO2 catalyst.
equation. The peak at 25.4ꢂ was used to calculate the average
crystal size using the Scherrer equation:
D ¼ Kl/b cos q
(1)
where D is the crystallite size, l the wavelength of X-ray radia-
tion (0.1541 nm), K is a constant usually taken as 0.89, and b is
the peak width at half-maximum height aer the subtraction of
equipment broadening, 2q ¼ 25.4ꢂ for anatase TiO2. The
average crystal sizes of pure TiO2, S-doped TiO2, Mo-doped TiO2
and Mo,S-codoped TiO2 were found to be around 12–17 nm.
Fig. 3 XRD patterns of the pure TiO2 (a) and Mo(0.06),S(0.05)-codo-
ped TiO2 nanocatalysts (b).
incorporation of metal and non-metal elements such as Mo and
S does not cause a signicant change in the crystalline structure
of TiO2, and a small shi in the positions of the anatase peaks
are observed in Mo(0.06),S(0.05)-codoped TiO2 nanocatalysts
compared to that of pure TiO2.
3.2. Morphological and elemental analysis
Fig. 4 shows the SEM micrographs of the pure and Mo,S-
codoped TiO2 nanoparticles. The morphology of the nano-
particles was found to be uniform with slightly agglomerated
spherical particles. Fig. 4 also reveals that the doping of Mo and
S does not cause any change in the morphology of TiO2.35
The average particle size (D, in nm) of the prepared catalysts
was determined using the XRD patterns according to Scherrer’s
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Fig. 8 Raman spectra of the pure TiO2, and Mo(0.06%),S(0.05%)-
codoped TiO2 nanocatalysts.
Fig. 6 TEM micrographs of pure TiO2 (A) and Mo(0.06),S(0.05)-
codoped TiO2 (B).
Fig. 7 UV-Vis DRS results of the pure TiO2, and Mo- and S-doped TiO2
nanocatalysts.
Fig. 5 shows the corresponding EDX results of Mo,S-codoped
TiO2 as the peaks of the nonmetal element S appear in the
spectrum. The EDX spectrum further provides direct proof that
Mo and S are successfully doped in TiO2 as their characteristic
peaks appears in the spectrum.37
Fig. 9 The photocatalytic results of MO degradation using the TiO2
nanoparticles doped with different amounts of S under UV and visible
light irradiation.
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Table 1 The photocatalytic results of MO degradation using the TiO2
nanoparticles doped with different amounts of S under UV and visible
light irradiation
UV light
Elem. (%)
0.05
0.10
0.15
0.20
0.25
Time (min)
5
10
20
30
45
60
80
100
130
160
220
280
1.6
3.2
12.7
13.9
27.8
32.1
42.7
50.3
58.6
66.1
71.4
81.2
87.9
95.5
8.3
8.6
1.3
8.9
19.1
30.9
39.1
46.8
54.5
65.7
73.8
84.1
88.8
91.1
100
18.8
30.1
34.9
47.6
54.7
64.3
73.4
85
10.1
14.5
29.1
39.8
51.6
64.5
77.3
86.2
99.2
100
17.4
25.5
34.9
43.9
54.7
61.4
68.6
75.3
86
91.5
98.3
100
92.7
Visible light
Elem. (%)
0.05
0.10
0.15
0.20
0.25
Time (min)
5
10
20
30
45
60
80
100
130
160
220
280
7.2
8
8.9
9.2
10.1
10.8
11.6
21.5
21.7
22.4
25.2
29.6
7.5
4.1
5.7
6.1
8.3
10.9
14.8
16.8
18.9
22.7
28
1.2
2.4
5.9
7.6
8.5
8.9
12.5
13.1
14.1
16.1
17.0
18.2
20.6
21.1
29.1
23.4
25
7.6
9.6
12.7
13.9
15.5
17.3
17.8
19.0
20.7
28.6
11.4
16.6
22.1
23.1
24.3
26.6
28.8
32.9
32.2
51.1
Fig. 10 The photocatalytic results of MO degradation using the TiO2
nanoparticles doped with 0.05% S and different amounts of Mo under
UV and visible light irradiation.
The size and morphology of the prepared pure TiO2 and
Mo,S-codoped TiO2 nanoparticles were also explored using
TEM. Selected images are exhibited in Fig. 6. As is obvious from
Fig. 6, the nanoparticles are successfully synthesized with
a spherical-shape morphology.
3.4. Raman analysis
In order to investigate the chemical properties of the prepared
nanocatalysts and the effect of binary doping on the chemical
structure of TiO2, Raman analysis was undertaken and the
corresponding results are shown in Fig. 8. Anatase TiO2 shows
six peaks as follows: 144 cmꢃ1 (Eg), 197 cmꢃ1 (Eg), 399 cmꢃ1
(B1g), 513 cmꢃ1 (A1g), 519 cmꢃ1 (B1g) and 639 cmꢃ1 (Eg), while
the rutile phase has four bands at 143 cmꢃ1 (B1g), 447 cmꢃ1 (Eg),
612 cmꢃ1 (A1g), and 826 cmꢃ1 (B2g).44 The ndings related to
Mo(0.06%),S(0.05%)-codoped TiO2 show identical signals of
pure anatase TiO2 with a slight chemical shi. In addition, the
intensity of the peaks for Mo(0.06%),S(0.05%)-codoped TiO2
varies from that of pure TiO2 which could be due to the surface
coverage of it by Mo nanoclusters.45
3.3. Band gap analysis using DRS spectroscopy
The DRS results of the prepared nanocatalysts are shown in
Fig. 7. The DRS results show a red shi in the absorption onset
value in the case of Mo and S doped TiO2, indicating decreases
in the band gap of the TiO2 photocatalyst. Non-metal elements
have been proven to be benecial in reducing the band gap
energy of TiO2 through mixing of their p-orbital with the O2p-
orbital, but the doping of transitional metals shis the TiO2
optical absorption edge from the UV to visible light range
without a prominent change in the TiO2 band gap.40–42 The
enhancement of absorbance in the UV-Vis region increases the
number of photogenerated electrons and holes to participate in
3.5. Photocatalytic performance of the prepared
nanocatalysts
the photocatalytic reaction, which results in the enhancement The photocatalytic degradation of MO by the undoped as well as
of the photocatalytic activity of TiO2.43
Mo, and S-doped TiO2 nanocatalysts under UV and visible light
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Table 2 The photocatalytic results of MO degradation using the Mo-
doped TiO2 nanoparticles with 0.05% S under UV and visible light
irradiation
UV light
Elem. (%)
0.03
0.06
0.09
Time (min)
5
29.9
54.6
81.7
94.3
99.6
100
24.5
40.3
68
84.7
95.9
100
32.3
59.5
78.7
92.3
98.7
100
10
20
30
45
60
Visible light
Elem. (%)
0.03
0.06
0.09
Time (min)
5
10
20
30
45
60
80
100
130
160
220
280
5.3
10.1
16.9
21.8
29.5
42.1
51
62.5
77.9
85.2
95.1
100
—
3.7
12.7
18.6
22.8
35.1
47.3
56.9
64
71.1
79.9
94.2
99.6
10.2
12.4
22.1
29.7
35.4
46.3
55.4
66.5
79
Scheme 1 Mechanism of the degradation of MO by pure TiO2 and
Mo,S-codoped TiO2 photocatalysts. The scheme shows the band gap
reduction and formation of the Schottky barrier in the Mo,S-codoped
TiO2 photocatalyst compared to that of the pure TiO2.
92.6
99
nanoparticles with 0.05% S/TiO2. Fig. 11 shows the degradation
of MO under UV and visible light irradiation for the Mo,S-
codoped TiO2 nanoparticles with 0.06% Mo and 0.05% S.
During the photocatalytic process, the absorption of the
photons by the photocatalyst leads to the excitation of the
electrons from the VB to the CB and generates electron–hole
pairs. The electron in the conduction band is captured by
oxygen molecules dissolved in the suspension and the hole in
the VB can be captured by OHꢃ or H2O species adsorbed on the
surface of the catalyst, to produce the hydroxyl radical. Hydroxyl
radicals then oxidize the pollutants. Thus, the recombination of
photogenerated electrons and holes is one of the most signi-
cant factors impacting the photoactivity of TiO2.43
The results exhibit that the Mo,S-codoped TiO2 nano-
particles prepared by the photochemical method have higher
activity than that of undoped TiO2 or TiO2 doped with either Mo
or S. In particular, the doping of TiO2 by either Mo or S increases
the photocatalytic activity, but codoping of Mo and S enhances
the photocatalytic activity with a higher rate. The signicantly
higher photocatalytic performance of Mo,S-codoped TiO2 may
be due to the synergetic effect of the co-doping of S and Mo in
the TiO2 nanoparticles. The presence of S reduces the band gap
of TiO2 and Mo nanoclusters located over the TiO2 catalyst
function as electron scavengers (the formation of a Schottky
barrier) and inhibit the charge recombination of photo-
generated electron–hole pairs at the surface of the catalyst as
shown in Scheme 1.46 Overall, it is speculated that the higher
photocatalytic activity of Mo,S-codoped TiO2, is due to either
one or a combination of the following factors: (i) increased light
absorption capability of Mo,S-codoped TiO2 compared to
Fig. 11 The photocatalytic results of MO degradation using the Mo,S-
codoped TiO2 nanoparticles with 0.05% S and 0.06% Mo.
irradiation was evaluated. Fig. 9 and Table 1 show MO degra-
dation using the S/TiO2 nanoparticles prepared by the sol–gel
method with different doses of S under UV and visible light
irradiation.
Fig. 10 and Table 2 show the degradation of MO under UV
and visible light irradiation for the Mo-doped TiO2
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undoped TiO2; (ii) alleviation of the surface poison phenom-
enon; (iii) reduction of the recombination rate of the photo-
generated electron–hole pairs. Mo can act as both an electron
and hole trap to reduce the recombination rate and enhance the
photocatalytic activity of TiO2.47
3 Y. Zhang, Z. R. Tang, X. Fu and Y. J. Xu, ACS Nano, 2010, 4,
7303.
4 X. Chen and S. S. Mao, Chem. Rev., 2007, 107, 2891.
5 C. Han, M.-Q. Yang, N. Zhang and Y.-J. Xu, J. Mater. Chem. A,
2014, 2, 19156.
Overall, we think that due to the excellent features deriving
from the synergetic effects of binary metal and non-metal
doping, the newly developed Mo,S-codoped TiO2 photocatalyst
can be a promising candidate for environmental applications
such as air and water purication.
6 N. Clifford, E. Palomares, K. Nazeeruddin, R. Thampi,
M. Grtzel and J. R. Durrant, J. Am. Chem. Soc., 2004, 126,
5670.
7 W. Zhao, C. C. Chen, X. Z. Li and J. C. Zhao, J. Phys. Chem. B,
2002, 106, 5022.
8 M. Jakob, H. Levanon and P. V. Kamat, Nano Lett., 2003, 3,
353.
9 R. Asahi, T. Morikawa, T. Ohwaki, K. Aoki and Y. Taga,
Science, 2001, 293, 269.
4. Conclusions
The sulfur and molybdenum codoped TiO2 photocatalysts of
Mo,S-codoped TiO2 were successfully prepared using a modied 10 D. M. Chen, D. Yang, Q. Wang and Z. Y. Jiang, Ind. Eng.
sol–gel method in conjunction with photochemical reduction Chem. Res., 2006, 45, 4110.
and the synthesized photocatalysts were used to degrade MO as 11 J. C. S. Wu and C. H. Chen, J. Photochem. Photobiol., A, 2004,
a model organic pollutant. The XRD patterns showed the highly
163, 509.
crystalline nature of the prepared catalysts in which only the 12 M. Anpo and M. Takeuchi, J. Catal., 2003, 216, 505.
anatase phase was detected in all the undoped and doped 13 T. Umebayashi, T. Yamaki, H. Itoh and K. Asai, Appl. Phys.
samples. Morphological analyses performed using SEM and
TEM showed relatively agglomerated spherical nanoparticles. 14 T. Umebayashi, T. Yamaki, S. Tanala and K. Asai, Chem. Lett.,
EDX and DRS analyses further conrmed the successful doping 2003, 32, 330.
of Mo and S in TiO2 and the synthesis of Mo,S-codoped TiO2. 15 T. Umebayashi, T. Yamaki, S. Yamamoto, A. Miyashita,
In general, our ndings showed that the codoping of TiO2 with S. Tanala, T. Sumita and K. Asai, J. Appl. Phys., 2003, 93, 5156.
Mo and S led to a smaller particle size, lower band gap value, red 16 T. Ohno, T. Mitsui and M. Matsumura, Chem. Lett., 2003, 32,
shi in the light absorption threshold, and the formation of 364.
a Schottky barrier at the interface between the TiO2 and Mo 17 T. Ohno, M. Akiyoshi, T. Umebayashi, K. Asai, T. Mitsui and
nanoclusters. The photocatalytic activity of the samples was M. Matsumura, Appl. Catal., A, 2004, 265, 115.
Lett., 2002, 81, 454.
tested using the degradation of MO as a model organic 18 T. Ohno, Water Sci. Technol., 2004, 49, 159.
pollutant and the ndings showed that Mo,S-codoped TiO2 19 W. Zhao, W. Ma, C. Chen, J. Zhao and Z. Shuai, J. Am. Chem.
nanoparticles have a higher photocatalytic activity than undo-
Soc., 2004, 126, 4782.
ped TiO2 as well as solely Mo- or S-doped TiO2 samples under 20 T. Tachikawa, S. Tojo, K. Kawai, M. Endo, M. Fujitsuka,
UV and visible light. This promotion in photocatalytic perfor-
mance was ascribed to the synergetic effect of S and Mo. In
T. Ohno, K. Nishijima, Z. Miyamoto and T. Majima, J.
Phys. Chem. B, 2004, 108, 19299.
conclusion, our results show Mo,S-codoped TiO2 is a promising 21 D. Chen, Z. Jiang, J. Geng, Q. Wang and D. Yang, Ind. Eng.
photocatalyst and could be a good candidate for various envi-
ronmental applications.
Chem. Res., 2007, 46, 2741.
22 L. Lin, R. Y. Zheng, J. L. Xie, Y. X. Zhu and Y. C. Xie, Appl.
Catal., B, 2007, 76, 196.
23 X. Li, R. Xiong and G. Wei, Catal. Lett., 2008, 125, 104.
24 F. Wei, L. Ni and P. Cui, J. Hazard. Mater., 2008, 156, 135.
Acknowledgements
We are grateful to the Council of the University of Kashan, Iran 25 D. B. Hamal and K. J. Klabunde, J. Colloid Interface Sci., 2007,
Nanotechnology Initiative Council and the University of Texas
311, 514.
at El Paso (UTEP) for providing nancial support. We also thank 26 K. Obata, H. Irie and K. Hashimoto, Chem. Phys., 2007, 339,
Dr Maryam Zarei-Chaleshtori for helping us with SEM and XRD 124.
analyses, Dr Peter Cooke from New Mexico State University 27 W. Pingxiao, T. Jianwen and D. Zhi, Mater. Chem. Phys., 2007,
(NMSU) for helping us with TEM analysis, Dr Luis Echegoyen’s 103, 264.
lab for access to the Raman instrument, and the College of 28 H. Huang, K. Liu, K. Chen, Y. Zhang, Y. Zhang and S. Wang,
Engineering at UTEP for allowing access to their SEM and XRD
instruments.
J. Phys. Chem. C, 2014, 118, 14379.
29 D. R. Zhang, Y. H. Kim and Y. S. Kang, Curr. Appl. Phys., 2006,
6, 801.
30 R. Khan, S. W. Kim, T.-J. Kim and C.-M. Nam, Mater. Chem.
Phys., 2008, 112, 167.
References
1 N. Zhang, M.-Q. Yang, S. Liu, Y. Sun and Y.-J. Xu, Chem. Rev., 31 X. Yang, L. Xu, X. Yu and Y. Guo, Catal. Commun., 2008, 9,
2015, 115, 10307. 913.
2 M.-Q. Yang, N. Zhang, M. Pagliaro and Y.-J. Xu, Chem. Soc. 32 X. Huili, Z. Huisheng, X. Dongchang and Z. Tao, J. Wuhan
Rev., 2014, 43, 8240.
Univ. Technol., Mater. Sci. Ed., 2008, 467–471.
15684 | RSC Adv., 2016, 6, 15678–15685
This journal is © The Royal Society of Chemistry 2016

View Article Online
Paper
RSC Advances
33 C. Liu, X. Tang, C. Mo and Z. Qiang, J. Solid State Chem., 40 L. Gomathi Devi, S. Girish Kumar, B. Narasimha Murthy and
2008, 181, 913. N. Kottam, Catal. Commun., 2009, 10, 794.
34 M. Hamadanian, S. Karimzadeh, V. Jabbari and D. Villagran, 41 R. Long and N. J. English, Phys. Rev. B: Condens. Matter
Mater. Sci. Semicond. Process., 2016, 41, 168. Mater. Phys., 2011, 83, 155209.
35 V. Jabbari, M. Hamadanian, A. Reisi-Vanani, P. Razi, 42 R. Long and N. J. English, Chem. Mater., 2010, 22, 1616.
´
´
S. Hoseinifard and D. Villagran, RSC Adv., 2015, 5, 78128.
43 H. Huang, X. Li, J. Wang, F. Dong, P. K. Chu, T. Zhang and
Y. Zhang, ACS Catal., 2015, 5, 4094.
44 K. L. Frindell, M. H. Bartl, A. Popitsch and G. D. Stucky,
Angew. Chem., Int. Ed., 2002, 41, 959.
45 K. R. Zhu, M. S. Zhang, Q. Chen and Z. Yin, Phys. Lett. A,
2005, 340, 220.
46 M. Hamadanian, M. Shamshiri and V. Jabbari, Appl. Surf.
Sci., 2014, 317, 302.
36 M. Hamadanian, A. Sadeghi Sarabi, A. Mohammadi Mehra
and V. Jabbari, Appl. Surf. Sci., 2011, 257, 10639.
37 M. Hamadanian, A. Reisi-Vanani, P. Razi, S. Hoseinifard and
V. Jabbari, Appl. Surf. Sci., 2013, 285, 121.
38 D. B. Hamal and K. J. Klabunde, J. Colloid Interface Sci., 2007,
311, 514.
39 H. Wei, W. Wu, N. Lun and F. Zhao, J. Mater. Sci., 2004, 39,
1305.
47 M. Hamadanian, V. Jabbari, M. Asad, M. Shamshiri and
I. Mutlay, J. Taiwan Inst. Chem. Eng., 2013, 44, 748.
This journal is © The Royal Society of Chemistry 2016
RSC Adv., 2016, 6, 15678–15685 | 15685