Characterization and catalytic performance of {Mo2O2S2}-based oxothiomolybdenum cyclic clusters supported on mesoporous SBA-15

Article abstract of DOI:10.1016/j.catcom.2015.01.025

Cyclic polyoxothiomolybdate clusters containing {Mo₂O₂S₂} building unit supported on SBA-15 have been prepared by immersion SBA-15 in the corresponding cluster's solution. The measurements of low angle X-ray diffraction (L

Full text of DOI:10.1016/j.catcom.2015.01.025

Catalysis Communications 64 (2015) 86–90
Contents lists available at ScienceDirect
Catalysis Communications
journal homepage: www.elsevier.com/locate/catcom
Short communication
Characterization and catalytic performance of {Mo O S }-based
2
2 2
oxothiomolybdenum cyclic clusters supported on mesoporous SBA-15
Zhifeng Xin ⁎, Wei Wei, Min Chen, Ai-Quan Jia, Qian-Feng Zhang ⁎
Institute of Molecular Engineering and Applied Chemistry, Anhui University of Technology, Ma'anshan, Anhui 243002, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Cyclic polyoxothiomolybdate clusters containing {Mo O S } building unit supported on SBA-15 have been pre-
2
2 2
Received 3 November 2014
Received in revised form 22 January 2015
Accepted 27 January 2015
Available online 29 January 2015
pared by immersion SBA-15 in the corresponding cluster's solution. The measurements of low angle X-ray dif-
fraction (LXRD), nitrogen adsorption, transmission electron microscopy (TEM) and energy dispersive X-ray
(EDX) spectroscopy indicated that the cyclic clusters were successfully loaded on SBA-15. The supported cata-
lysts were tested in thiophene hydrodesulfurization at different temperatures, respectively. Results show that
the supported catalysts have an excellent desulfurization catalytic performance for thiophene.
Keywords:
Mo O S -based wheels
2 2 2
©
2015 Published by Elsevier B.V.
Heterogeneous catalysis
Thiophene
Hydrodesulfurization
1
. Introduction
the supported catalysts was investigated at four temperatures,
respectively.
Cyclic [Mo
linking of [Mo
2 2 2
O S ]-based molybdenum clusters result from the cyclic
2
+
2 2 2
O S ]
through double hydroxyl bridges around anion-
2. Experimental
ic templates, most commonly poly-carboxylate ligands [1,2]. This class
of compounds exhibits unique electron structure and efficient electro-
2.1. Materials
2
catalytic properties [3–5]. Molybdenum disulfide (MoS ) and its deriva-
tives have been widely used as catalysts for hydrodesulfurization (HDS)
of petroleum [6,7]. The route preference depends on several factors such
as support composition, promoter, S-containing molecules and catalyst
preparation [7,8].
Tetraethyl orthosilicate (98.0%), Pluronic P123 (EO20PO70EO20) and
thiophene were purchased from Energy Chemical, and used without
further purification. SBA-15 was synthesized according to the reported
method [11] and characterized with low angle X-ray diffraction
2 2 2
Cyclic [Mo O S ]-based molybdenum clusters displayed flexible and
2
(LAXRD) and N adsorption measurement. All other chemicals were an-
adaptable cyclic oxothiomolybdenum rings exhibiting an open inner
available cavity [9]. The encapsulated ligands should also have an
influence upon the hydrodesulfurization (HDS) process. And these
structural features afford this class of compounds more exciting cat-
alytic properties. SBA-15 is highly ordered hexagonal mesoporous
silica with high surface area [10]. As a catalyst, SBA-15 is not often di-
rectly used in reactions. So adding active elements onto the inner
surface of the SBA-15 is a necessary process [11]. In this study,
alytical grade and were purchased from Sinopharm Chemical Reagent
Co., Ltd. (China).
2.2. Characterization
Powder X-ray diffraction (XRD) experiments were recorded on a
Bruker D8 Advance (operating at 40 kV and 20 mA) with Ni-filtered
Cu Ka radiation at 1.5406 (Å) with a speed of 0.1 min per step of
0.05°. The thermo-gravimetric analysis (TGA) was carried out on a
three [Mo
O) ]·20H
dodecamolybdenum: Cs
2
O
2
S
2
]-based wheels: K2 − x(NMe
O ([(Mo ]; x = 1, 2) and aromatic acid modified
[Mo12 12(OH)12-(C )]·15H O·6DMF
12(OH)12(C )]·22H O (Mo12BTC)
DBC = 1,4-benzenedicarboxylate, BTC = 1,3,5-benzenetricarboxylate)
4 x 2 10
) -[I Mo10O S10(OH)10
(
H
2
5
2
2
O
2
S )
2 n
Shimadzu DTG-60H thermo-gravimetric analyzer in the N
30 mL min
2
flow of
and the heating rate of 1 °C min . TEM images were
collected on a JEM-2100 electron microscope at 200 kV. N adsorption/
−
1
−1
2
12
O S
H O
8 4 4
2
(
(
Mo12BDC), K
3
[Mo12
O
12
S
9
H
3
O
6
2
2
desorption isotherms were obtained at 77 K with a Micromeritics ASAP
[
12] were loaded on an SBA-15 mesoporous material by the impreg-
2020 M + C system after the samples were first degassed at 120 °C for
6 h. H NMR spectra were recorded at room temperature on a Bruker
1
nation method. The thiophene hydrodesulfurization performance for
AC 400 MHz spectrometer using DMSO-d6 as the NMR solvents. IR spec-
tra were taken from samples embedded in KBr pellets using a Nicolet
6700 FT-IR spectrophotometer. X-ray Photoelectron Spectroscopy
⁎
Corresponding authors.
E-mail addresses: xinzf521@ahut.edu.cn (Z. Xin), zhangqf@ahut.edu.cn (Q.-F. Zhang).
http://dx.doi.org/10.1016/j.catcom.2015.01.025
566-7367/© 2015 Published by Elsevier B.V.
1

Z. Xin et al. / Catalysis Communications 64 (2015) 86–90
87
(
XPS) was carried out on a Thermo ESCALAB 250XI multifunctional
3. Results and discussion
imaging electron spectrometer using the binding energy of C as the
internal standard. The gas chromatography was obtained on a Shimadzu
GC-2010 plus gas chromatograph connected a Rtx-wax column and a hy-
3.1. Preparation and characterization of SBA-15 supported [Mo
based wheels
2 2 2
O S ]-
2
drogen flame ionization detector (FID) using N as the carrier gas at a
flow rate of 1.00 mL/min. Column temperature was first raised to 70 °C
and maintaining for 4 min, and then raised to 120 °C with 10 °C/min
and keeping for 6 min. The injection temperature and detector tempera-
tures are 200 °C and 220 °C, respectively. Sample quantity is 0.5 μL with a
split ratio of 10:1.
K
2 − x(NMe
to the literature [13]. The [I
consists of five [Mo
4
)
x
[I
2
Mo10
O
10
S
10(OH)10(H
2 5
O) ] was prepared according
2
−
2
Mo10 10(OH)10(H
S
10
O
2
O)
5
]
molecular
2
S
2
O
2
] units which connected to each other by
−
hydroxo double bridges around two I anionic templates to form a
ten membered ring [13]. In the cyclic structure of Mo12BDC, each car-
boxylate group bridged the two adjacent Mo atoms of the same
2
+
2
2
.3. Preparation
[Mo
2
2 2
S O ]
moiety through single Mo\O interactions. Consequently,
the four Mo atoms which connected to carboxylate groups retain an
octahedral environment, whereas, the other eight Mo atoms display
square-pyramidal arrangements (Fig. S1b) [9]. The structure of
Mo12BTC can be described as a dodecanuclear ring encapsulated with
a benzenetricarboxylate anion, each carboxylate group bridging two
.3.1. K2 − x(NMe
2 − x(NMe
was synthesized according to reference [12]. IR (KBr pellet): the ab-
4
)
x
[I
2
Mo10
O
10
S
10(OH)10(H
2
O)
5
]·20H
]·20H
2
O ([(Mo
2
O
2
S
2
)
n
])
K
4
)
x
[I
2
Mo10
O
10
S10(OH)10(H
2
O)
5
2
O ([(Mo
2
O
2
S
2
)
n
])
−
1
sorption peaks at 970, 525 and 488 cm
attributed to vibrations of
ν(Mo_O), ν(Mo\OH\Mo) and ν(Mo\S\Mo), respectively. Pale
orange crystals were obtained by dissolving 0.2 g of the yellow mi-
Mo centers (Fig. S1c) [9,12].
1
The H NMR spectra of Cs
2
[Mo12BDC] and K
3
[Mo12BTC] were record-
. The spectrum of [Mo12BDC]2 (Fig. S2a) displayed three
−
crocrystalline powder in 20 mL DMF/H
2
O (1/5) and allowing the so-
ed in DMSO-d
6
lution to stand for several days at room temperature.
sharp resonances at δ = 5.06, 10.6 and 11.47 ppm with an integration of
:2:1, respectively. The low frequency signal at δ = 5.07 ppm
1
2
.3.2. Cs
Cs [Mo12
2
2
[Mo12
O
12
S
12(OH)12(C
8
H
4
O
O
4
)]·15H O·6DMF (Mo12BDC)
2
)]·15H O·6DMF (Mo12BDC) was
2
corresponded to the four aromatic protons of the encapsulated BDC
guest, and the signals at 10.6 and 11.47 ppm corresponded to the twelve
protons of twelve bridging hydroxyls. The H NMR spectrum (Fig. S2b)
O
12
S
12(OH)12(C
8
H
4
4
1
synthesized according to reference [9]. 1H NMR (D6-DMSO/ppm):
d = 11.43 (s, 4H), 10.56 (s, 8H), 5.07 ppm (s, 4H) (Fig. S2a); IR (KBr
3
of K [Mo12BTC] showed two sharp resonances at δ = 5.92 and
−
1
pellet): 970.51, ν = 1617(s), 1540(s), 1382(s), 966(s), 530(s) cm
TGA: loses 15 lattice waters (ca. 9.4%) from room temperature to
7 °C, three lattice DMF molecules (ca. 7.4%) from 47 °C to 110 °C, six
.
10.06 ppm with an integration of 1:4. The low frequency signal at
δ = 5.07 ppm corresponded to the three aromatic protons of the encap-
sulated BTC guest, and the signals at 10.6 ppm corresponded to the
twelve protons of twelve bridging hydroxyl [15].
4
constitutive water molecules from the decomposition of 12 μ-OH (4%)
and three coordinated DMF molecules (7.4%) between 110 and 389 °C,
the loss after 389 °C corresponding to the ligand BDC (see Fig. S3b).
The single crystal was obtained by dissolving the raw product in the
mixed solvent of DMF/H
in Fig. S1b.
2 2 2 n
The IR spectra of [(Mo O S ) ]/SBA-15 (Fig. S4a), Mo12S12BDC/SBA-
15 (Fig. S5a) and Mo12 12BTC/SBA-15 (Fig. S6a) clearly showed bands
S
associated with both the support and the molybdenum sulfide clusters.
For instance, the strong peak for stretching of the Si\O\Si near
2
O (1/1). The crystal structure was displayed
−
1
−1
1085 cm , bending vibration of Si\O\Si near 800 cm , H\O\H
−
1
bending vibrations of physisorbed water at 1634 cm , and the vibra-
−
1
2
.3.3. K
[Mo12
according to reference [9]. H NMR (DMSO-D
3
[Mo12O
12
S12(OH)12(C
9
H
3
O
6
)]·22H
2
O (Mo12BTC)
O (Mo12BTC) was synthesized
): d = 10.04 (s, 12H),
.93 ppm (s, 3H) (Fig. S2b); IR (KBr pellet): ν = 1610(s), 1544(s),
438(s), 1370(s), 974(s), 927(s), 531 cm−1 (s). TGA: Loss of about 22
tions near 1388, 1102, 1063, 969, 669 and 465 cm
as the characteristics of the [Mo ]-based cyclic clusters [12–15].
]-based cyclic clusters had
can be referred
K
3
O
12
S
12(OH)12(C
9
H
3
O
6
)]·22H
2
2 2 2
O S
1
6
The results further indicated that [Mo
2 2 2
O S
5
1
been adsorbed in the support SBA-15.
2 2 2 n
The LXRD pattern of SBA-15, [(Mo O S ) ]/SBA-15, Mo12BDC/SBA-
lattice water molecules below 270 °C and six constitutive water mole-
cules (from the 12 OH bridging groups) from 270 to 430 °C (see
Fig. S3c).
15 and Mo12BTC/SBA-15 showed a strong peak corresponding to
(100) plane and two weak peaks corresponding to (110) and (200)
planes of ordered hexagonal mesoporous materials (Fig. S7). The simi-
larity in peak intensities and positions indicates that the structure of
SBA-15 is unaffected by the activation process and the binding of
molybdenum sulfide clusters. Nonetheless, the peaks corresponding
2
.4. Synthesis of cluster anchored onto SBA-15: 150 mg SBA-15
Preparation of clusters anchored onto SBA-15: 150 mg SBA-15 was
2 2 2 n
to the (100) plane of [(Mo O S ) ]/SBA-15, Mo12BDC/SBA-15 and
degassed at 120 °C under vacuum for 6 h. 20 mg Mo12
Mo12BTC was dissolved in deionized water which was degassed with
bubbling for 15 min. The activated SBA-15 (1.5 g) was suspended
into the above solution, and the mixture was stirred at 60 °C for 20 h.
The excess water was removed using a rotary evaporator, and the
resulting yellow solid was dried at 80 °C overnight. The product was
washed with deionized water and MeOH until the filtrate became color-
less. Finally the solid product was dried in an oven at 120 °C for 8 h and
stored for further applications.
S
12, Mo12BDC or
Mo12BTC/SBA-15 slightly shifted to lower angles and the peak inten-
sity slightly decreased, which indicated a slight increase of the pore
size and reduction of the period of ordered lattice. In the loading pro-
cedure, molybdenum sulfide clusters occupied the inner space of
SBA-15 and filled part of the smaller pores, which lead to the pore
size distribution shifted to larger direction and the peaks shifted to
lower angles [6].
N
2
In good agreement with LXRD data, the transmission electron micro-
scope (TEM) images (Fig. 1) of [(Mo O S ) ]/SBA-15, Mo12BDC/SBA-15
2 2 2 n
and Mo12BTC/SBA-15 displayed the similar ordered mesoporous struc-
ture with SBA-15. The particles or clusters loaded on the channel cannot
be seen in the TEM images, but the EDX spectra (Fig. S8) showed the
peaks of Mo and S, which indicated that the molybdenum sulfide clus-
ters already loaded in the channels or on the surface. In the impregna-
tion process, these clusters loaded on the channel surface didn't in the
form of large nuclei but in the form of single molecular layer. The XRD
2
.5. Catalyst testing
In a typical experiment, 0.1 g thiophene, 10 mL ethanol and 5 mg
catalyst powder were added in Teflon-lined autoclave, and the reaction
was performed under vigorous stirring at 200, 240, 280 and 320 °C for
2
0 h, respectively. The resulted mixture was filtered, and the filtrate
was characterized with a gas chromatograph and gas chromatography
spectra (Fig. S9) showed the amorphous structure of [(Mo
2 2 2 n
O S ) ]/
mass spectrometry (GC–MS).
SBA-15, Mo12BDC/SBA-15 and Mo12BTC/SBA-15, which also indicated

88
Z. Xin et al. / Catalysis Communications 64 (2015) 86–90
2 2 2 n
Fig. 1. TEM images of SBA-15 (a), [(Mo O S ) ]/SBA-15 (b), Mo12BDC/SBA-15 (c), and Mo12BTC/SBA-15 (d).
2 2 2 2 n
Fig. 2. N sorption isotherms of SBA-15 (a), [(Mo O S ) ]/SBA-15 (b), Mo12BDC/SBA-15 (c), and Mo12BTC/SBA-15 (d). The insets were the corresponding pore size distribution curves.

Z. Xin et al. / Catalysis Communications 64 (2015) 86–90
89
that the cluster (Mo
on the pore wall of SBA-15.
The pore structure of the sample of SBA-15, [(Mo
Mo12 12BDC/SBA-15 and Mo12BTC/SBA-15 was also detected by low
pressure N sorption measurement at 77 K. The characteristic shape of
sorption isotherms (type IV isotherm with an H1 hysteresis loop)
of SBA-15 did not change by the loading of the molybdenum sulfide
clusters, which indicated that the original pore structure of SBA-15 is
2
maintained after the impregnation step. The obvious decrease of N up-
takes indicated that the polyoxothiomolybdate clusters occupied the
partial inner surface of SBA-15 through the impregnation procedure
2
O
2
S
2
)
n
, Mo12BDC or Mo12BTC uniformly dispersed
corresponded to the reduction of molybdenum (Mo5+ to Mo4+). This
result was in accordance with that of XPS.
2 2 2 n
O S ) ]/SBA-15,
S
3.4. Effect of the temperature on the catalytic performance
2
N
2
Catalytic activity of the catalysts was evaluated in a stainless auto-
clave reactor in a temperature range of 200–320 °C for 20 h. The
thiophene/ethanol system after hydrodesulfurization catalyzed by
these supported catalysts at different temperatures was characterized
by gas chromatography (Figs. S13–S15). Fig. 3 displayed the conversion
rate and selectivity of thiophene desulfurization catalyzed by the support-
ed catalysts. The results of GC–MS testing indicated the desulfurization
(
1
1
Fig. 2) [6]. The pore width distributions of SBA-15, [(Mo
5, Mo12S
2
O
2
S
2
)
n
]/SBA-
12BDC/SBA-15 and Mo12BTC/SBA-15 were all from 5.6 nm to
0 nm, but the average pore width of [(Mo ]/SBA-15 (7.15 nm),
12BDC/SBA-15 (6.91 nm) and Mo12BTC/SBA-15 (7.34 nm) was
slightly larger than that of bare SBA-15 (6.32 nm), which is agreement
with that of LAXRD. From the N sorption isotherms and pore distribu-
2 2 2 n
O S )
Mo12
S
2
tion curves (Fig. 2 inset), it is evident that the loading of the clusters into
the SBA-15 slightly decreased its surface area and pore volume. Due to
part surface area and the micro-pore volume was occupied by clusters,
the proportion of macro-pore increased and average pore diameter
slightly increased. The data of the BET surface area, pore volume and av-
erage pore diameter of the samples are presented in Table 1.
3
.2. Stability of the supported catalysts
The shape of TGA curves (Fig. S10) of the supported catalysts is sim-
ilar to that of pure clusters (Fig. S4). For [(Mo O S ) ]/SBA-15, the
2 2 2 n
weight loss before 150 °C attributed to the adsorbed water, lattice
water and coordinated water, and between 150 and 350 °C attributed
to the constitutive water molecules (from the OH bridging groups). As
for Mo12S12BDC/SBA-15, the weight loss before 398 °C attributed to
the adsorbed solvent, lattice water molecules, coordinated water and
six constitutive water molecules (from the sixteen OH bridging groups).
And for Mo12BTC/SBA-15, loss of about adsorbed water and lattice water
between room temperature and 270 °C, six constitutive water mole-
cules (from the 12 OH bridging groups) between 270 and 430 °C [9].
So the lattice water, coordinated water and constitutive water mole-
cules of the clusters may be lost in the catalytic procedure from 200 °C
to 320 °C, however, the IR spectra (Figs. S4–S5) indicated that the
−
1
Mo\S\Mo bond (the vibration at 493 cm ) of the three supported
catalysts still exists after being catalyzed from 200 °C to 320 °C. The
Mo (3d) XPS (Fig. S11) curves of [(Mo
the Mo
2
O
2
S
2
)
n
]/SBA-15 indicated that
(228.6 eV, Fig. S11d, e) appeared after catalyzed at 280 °C
and 320 °C.
4
+
3
.3. Temperature-programed reduction (TPR) experiment
3
3.0 mg of sample was added into a quartz U-tube reactor connected
to a thermal conduction detector. In order to remove the water from the
catalysts, the samples were pretreated in flowing dry N (30 mL/min) at
00 °C for 2 h. After cooled to room temperature, the gas mixture of hy-
2
1
drogen/argon (9%/91%) passed through the U-tube reactor at a flow rate
of 20 mL/min. And the temperature of the reactor was increased to
7
00 °C at a heating rate of 10 °C/min. The hydrogen absorption appeared
from 280 °C to 340 °C and reached a peak at 320 °C (Fig. S12), which
Table 1
Textural properties of the supported catalysts.
Samples
BET surface area
Pore volume
(cm /g)
Pore width
(nm)
2
3
(m /g)
[
(Mo
2
O
2
S
2
)
n
]/SBA-15
498.45
516.86
540.01
792.23
0.89
0.89
0.99
1.08
7.15
6.91
7.34
6.32
Mo12
Mo12
SBA-15
S12BDC/SBA-15
12BTC/SBA-15
Fig. 3. Conversion rate ( ) and selectivity ( ) of thiophene hydrodesulfurization for the
S
2 2 2 n
catalysts of [(Mo O S ) ]/SBA-15 (a), Mo12BDC/SBA-15 (b), and Mo12BTC/SBA-15 (c), re-
spectively, at 200 °C, 240 °C, 280 °C, and 300 °C.

90
Z. Xin et al. / Catalysis Communications 64 (2015) 86–90
2 2 2
Fig. 4. Possible mechanism of thiophene hydrodesulfurization on cyclic [Mo O S ]-based catalyst.
products of 1-butanol and tetrahydro-thiophene. The selectivity was cal-
culated by the ratio of the yield of 1-butanol to the conversion rate of thio-
phene. Fig. 3 indicated that the catalytic activity of the supported catalyst
increased with increasing temperature. After 280 °C, the thiophene con-
version rate increased obviously, which is in accordance with the result
Appendix A. Supplementary data
Supplementary data to this article can be found online at http://dx.
doi.org/10.1016/j.catcom.2015.01.025.
of H
2
-TPR experiment, and HDS selectivity ratio is above 90%.
molecule was adsorbed on the cat-
In HDS catalytic reactions, the H
2
References
alyst in the form of S–H bond which can migrate to the adsorbed thio-
phene [16]. The desulfurization mechanism of thiophene included two
procedures (Fig. 4): hydrodesulfuzation and direct desulfurization.
The hydrogen atom transferred from S–H bond to the C_C of thio-
phene, which can saturate the aromatic thiophene ring making the de-
sulfurization easier, and then break the C\S bond. In the desulfurization
step, the hydroxyl in the reaction system attacked and connected with
the butyl to form 1-butanol.
[
[
1] E. Cadot, F. Sécheresse, Chem. Commun. (2002) 2189–2197.
2] J.F. Lemonnier, S. Duval, S. Floquet, E. Cadot, Isr. J. Chem. 51 (2011) 290–302.
[3] A. Hijazi, J.C. Kemmegne-Mbouguen, S. Floquet, J. Marrot, C.R. Mayer, V. Artero, E.
Cadot, Inorg. Chem. 50 (2011) 9031–9038.
[
[
[
4] S. Duval, S. Floquet, C. Simonnet-Jégat, J. Marrot, R.N. Biboum, B. Keita, L. Nadjo, M.
Haouas, F. Taulelle, E. Cadot, J. Am. Chem. Soc. 132 (2010) 2069–2077.
5] B. Keita, S. Floquet, J.F. Lemonnier, E. Cadot, A. Kachmar, M. Bénard, M.M. Rohmer, L.
Nadjo, J. Phys. Chem. C 112 (2008) 1109–1114.
6] D. Valencia, T. Klimova, Appl. Catal. B 129 (2013) 137–145.
[7] A. Cho, J.J. Lee, J.H. Koh, A. Wang, S.H. Moon, Green Chem. 9 (2007) 620–625.
8] (a) D. Valencia, T. Klimova, Catal. Today 166 (2011) 91–101;
[
(
b) A. Tuxen, J. Kibsgaard, H. Gøbel, E. Lægsgaard, H. Topsøe, J.V. Lauritsen, F.
Besenbacher, ACS Nano 4 (2010) 4677–4682;
4
. Conclusions
(c) J. Kibsgaard, A. Tuxen, K.G. Knudsen, M. Brorson, H. Topsøe, E. Lægsgaard, J.V.
Lauritsen, F. Besenbacher, J. Catal. 272 (2010) 195–203.
2 2 2 n
The three clusters [(Mo O S ) ], Mo12BDC and Mo12BTC were sup-
[
9] J.F. Lemonnier, S. Floquet, J. Marrot, E. Terazzi, C. Piguet, P. Lesot, A. Pinto, E. Cadot,
ported on SBA-15 with the impregnation method and were character-
ized by LXRD, TEM, IR spectra, EDX and N sorption measurements.
The desulfurization catalytic activities of the supported catalysts were
investigated with thiophene at 200, 240, 280 and 320 °C, respectively.
Chem. Eur. J. 13 (2007) 3548–3557.
10] (a) D. Zhao, J. Feng, Q. Huo, N. Melosh, G.H. Fredrickson, B. Chmelka, G.D. Stucky,
[
2
Science 279 (1998) 548–552;
(
b) B. Li, W. Ma, J. Liu, C. Han, S. Zuo, X. Li, Catal. Commun. 13 (2011) 101–105.
[11] A. Taguchi, F. Schuth, Microporous Mesoporous Mater. 77 (2005) 1–45.
12] E. Cadot, B. Salignac, S. Halut, F. Sécheresse, Angew. Chem. Int. Ed. 37 (1998)
11–613.
[13] E. Cadot, B. Salignac, J. Marrot, A. Dolbecq, F. Sécheresse, Chem. Commun. (2000)
61–262.
14] G.R. Bardajee, R. Malakooti, I. Abtin, H. Atashin, Microporous Mesoporous Mater. 169
2013) 67–74.
[15] A. Hijazi, J.C. Kemmegne-Mbouguen, S. Floquet, et al., Dalton Trans. 42 (2013)
848–4858.
[
2 2 2
The results indicated that these [Mo O S ]-based cyclic clusters exhibit
6
an excellent desulfurization catalytic activity at relatively lower temper-
ature, which is obviously higher than those of (Co)MoS catalysts [17].
2
2
[
(
Acknowledgments
4
[
[
16] X.-Q. Yao, Y.-W. Lia, H. Jiao, J. Mol. Struct. THEOCHEM 726 (2005) 81–92.
17] M. Li, H. Li, F. Jiang, Y. Chu, H. Nie, Catal. Today 149 (2010) 35–39.
This work was financially supported by the National Natural Science
Foundation of China (grant nos. 21101003 and 90982008).