NiO promoted CuO-NiO/SBA-15 composites as highly active catalysts for epoxidation of olefins

Article abstract of DOI:10.1039/c6nj01654e

In this paper, CuO-NiO supported on mesoporous silica SBA-15 was developed using the ultrasonic post-grafting method. The bi-metallic oxides were well-dispersed in very small sizes in the mesoporous channels, and the presence of NiO enhanced the surface content of CuO, leading to a redistribution of CuO and good dispersion of CuO nanoparticles, which were characterized by high-resolution transmission electron microscopy (HRTEM), XRD and N₂ adsorption and desorption isotherm examination. Compared with the CuO/SBA-15 or NiO/SBA-15, the electron transfer that occurred between the two metal oxides and high dispersion of the active components improved the overall selective olefin oxidation.

Full text of DOI:10.1039/c6nj01654e

View Article Online
View Journal
NJC
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: Y. Tang, H. Gao,
M. Yang, G. Wang, J. Li, H. Zhang and Z. Tao, New J. Chem., 2016, DOI: 10.1039/C6NJ01654E.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/njc

Page 1 of 7
PNl ee aws eJ do ou rnn oa tl ao df j uC sht emm ai rs gt ir ny s
View Article Online
DOI: 10.1039/C6NJ01654E
Journal Name
ARTICLE
NiO Promoted CuO-NiO/SBA-15 Composites as Highly Active Catalysts for
Epoxidation of Olefins
Received 00th January 20xx,
Accepted 00th January 20xx
Yinhai Tang, Hongyi Gao, Mu Yang*, Ge Wang*, Jie Li, Huan Zhang, Zhang Tao
In this paper, CuO-NiO supported on mesoporous silica SBA-15 was developed using the ultrasonic post-
grafting method. The bi-metallic oxides are well-dispersed in very small sizes in the mesoporous channels, and
the presence of NiO enhances the surface content of CuO, leading to a redistribution of CuO and the well
dispersion of CuO nanoparticles, which were characterized by high-resolution transmission electron
DOI: 10.1039/x0xx00000x
www.rsc.org/
microscopy (HRTEM), XRD and N absorption and desorption isotherms examinations. In comparison with
2
the CuO/SBA-15 or NiO/SBA-15, the electron transfer that occurs between the two metals oxide and high
dispersion of the active components improves the overall selective oxidation of olefin.
overoxidation. Given these limitations, hybrid catalysts have
attracted widespread interest because of their markedly better
properties than those of either of the constituent metal oxides.
1
. Introduction
2
1
Selective oxidation of olefin is of crucial importance in the
1
-4
Ravasio et al. synthesized a bifunctional supported copper
catalyst CuO/Al O , which showed an excellent catalytic
synthesis of fine chemicals and intermediates. One example
is styrene, while styrene epoxide is an important intermediate
for the synthesis of complex components for commercial
procedures. For instance, it can be used for the production of
chiral aziridines with retain their configuration, as well as
chiral ring-opened products with alcohols and amines, etc.,
due to the ease with which epoxide ring reacts with a wide
range of uncleophiles.
pathway of styrene causes many other products makes selective
epoxidation difficult.
Nowadays, much attention has been paid to the transition-
metal oxides heterogeneous catalysts for the selective oxidation
2
3
2
2
property for the one-pot epoxidation of alkenes. Ye et al.
deposited CuO nanoparticles on the surface of Ag nanowires,
and the novel CuO@Ag nanowires showed a synergistic effect,
leading to outstanding catalytic activities in the epoxidation of
5
6
7
2
3
trans-stilbene under mild reaction condition. Our group
prepared a hybrid Fe O -CuO@meso-SiO catalyst using a
8
-10
3
4
2
However, the diverse oxidation
multi-step assembly method, and the meso-structure and
multiple functionalities (Fe O -CuO) showed high selectivity
1
1-13
3
4
2
4
for styrene oxide.
Recently, a new bimetallic oxide system of CuO-NiO has
2
5,26
1
4-16
been developed,
which has many applications in catalytic
of olefin.
Among these, copper oxide has been employed in
processes. It is well known that heterogeneous copper catalysts
are effective in oxidation, while the presence of traces of nickel
a variety of processes due to its low-cost, being naturally
abundant, having good catalytic performance and being
environmentally friendly.
2
7,28
1
7,18
oxide ensures an improved and stabilization of copper.
However, the aggregation and
Among those researches, a CuO-NiO system has been studied
in selective hydrogenation and dehydrogenation, while its
application for the epoxidation of olefins is the subject of
ongoing research.
In this paper, we report a NiO promoted CuO-NiO/SBA-15
composites synthesized via the ultrasonic post-grafting method.
restructuring of the CuO nanoparticles still limit their
application. Recently, copper oxide is introduced into or
encapsulated with ordered mesoporous materials since their
various pore structures and large surface area favor the catalytic
1
9
nanoparticles dispersal and stablility. For example, Chen et al.
coated CuO nanoclusters with mesoporous SiO using the one-
2
With the assistance of -NH groups on the SBA-15 internal
2
pot solvothermal synthetic method, which showed higher
activity and stability in olefin epoxidation reaction than that of
surfaces, the precursors were absorbed into the mesoporous
channels easily under ultrasonic conditions. The presence of
NiO improved the dispersion of CuO-NiO in the mesoporous
channels, giving significantly improved activity for the
epoxidation of olefins with a remarkably high selectivity.
Moreover, the increase of a small amount of NiO promotes the
overall catalytic performance of the catalysts.
2
0
commercial CuO. However, the unique catalytic sites still
have the drawback of relative-low catalytic activity or
Beijing Key Laboratory of Function Materials for Molecule & Structure
Construction, School of Material Science and Engineering, University of Science
and Technology Beijing, Beijing, 30 Xueyuan Road, 100083, P. R. China. E-mail:
yangmu@ustb.edu.cn; gewang@mater.ustb.edu.cn
†
Electronic Supplementary Information (ESI) available: [FT-IR, TGA and HRTEM].
See DOI: 10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

PNl ee aws eJ do ou rnn oa tl ao df j uC sht emm ai rs gt ir ny s
Page 2 of 7
ARTICLE
Journal Name
2
. Experimental
the ultrasonic post-grafting method without VfiielwteArritinclge Ontlhinee
DOI: 10.1039/C6NJ01654E
precursor off during the synthesization process.
2
.1 Materials.
2
.4. Characterization.
Cupric nitrate (Cu(NO ) ·3H O), nickel nitrate (Ni(NO ) ),
3
2
2
3 2
tetraethyl-orthosilicate
[(OC H ) Si,
TEOS],
tert-butyl The Fourier-transform infrared (FT-IR) spectra were examined
2
5 4
hydroperoxide (TBHP) and HCl (36-38 wt.%) were purchased using a Nicolet 6700 spectrometer. The morphology and
from Beijing Chemical Reagent Company. Pluronics P123 (Mw structure of CuO-x NiO/SBA-15 was examined using high-
=
5800) and all of the olefins were supplied by SigmaeAldrich resolution transmission electron microscopy (HRTEM) on a
and Alfa Aesar, respectively. All reagents were used as JEM-2100F equipped with an energy-dispersive X-ray (EDX)
received without further purification.
operated the accelerating voltages of 200 kV. The crystalline
phases were analyzed by XRD pattern on M21X
a
2
.2. Preparation of modified SBA-15.
diffractometer (MAC Science Co. Ltd., Japan) using a Cu Ka
radiation (λ = 1.541 Å) source at 40 kV and 200 mA. Nitrogen
adsorption-desorption isotherms were obtained using an
AUTOSORB-1C analyzer (USA Quantachrome Instruments) at
First, the SBA-15 was synthesized following previously
reported methods. In a typical procedure, P123 (4.0 g) as the
structure-directing agent was first dissolved in 30 mL H O at 35
1
6
2
77 K, and the specific surface area was measured using the
ºC, and 120 mL 2.0 M HCl aqueous solution was added.
Tetraethyl-orthosilicate (TEOS, 8.5 g) was added dropwise as
the silica source, and the mixture was stirred at 35 ºC for 24 h.
The resultant gel was transferred into a Teflon-sealed autoclave
and heated to 110 ºC for 24 h. After cooling down, the
precipitate was recovered and washed with de-ionized water
several times. The obtained SBA-15 with template was then
dried at 80 ºC overnight for further modification.
Brunauer-Emmett-Teller (BET) method. Pore size distributions
were calculated using the Barrett-Joyner-Halenda (BJH)
method from the adsorption branches of the isotherms. Cu and
Ni elemental analysis was performed by inductively coupled
plasma-atomic emission spectrometry (ICP-AES) using a
Vavian 715-ES. X-ray photoelectron spectroscopy (XPS) data
was obtained with an Escalab 220i-XL electron spectrometer
from VG Scientific using 300W Al Ka radiation. Finally, the
catalytic properties were analyzed by Agilent 7890/5975C-
GC/MSD.
The obtained SBA-15 was modified with -CH and -NH
3
2
2
9
according to our reported procedure. In a typical procedure,
as-prepared SBA-15 (2.0 g) was dispersed into dry toluene (150
mL) under nitrogen atmosphere. Then 10 mL of
trimethylchlorosilane (TMCS) was added dropwise, and the
2
.5. Catalytic properties.
mixed solution was stirred at 80 ºC for 8h under reflux. After The catalytic epoxidation of styrene was performed in a two-
that, the solid was filtered and washed with toluene and alcohol necked round-bottom flask fitted with a reflux condenser. First,
several times, and then calcined at 350 ºC for 6 h to remove the the catalyst containing 0.0129 mmol of CuO, 5.0 mL
structure-directing agent P123. Then, the obtained sample (2.0 acetonitrile, 3.0 mmol of styrene and 0.02 mL of nitrobenzene
g) was dispersed into 150 mL dry toluene, and 6.0 mL 3- as internal standard for GC-MS analysis were mixed within the
aminopropyltriethoxylsilane (APTES) was added dropwise. flask and the reaction temperature was maintained at 80 ºC.
The mixed solution was stirred at 25 ºC for 12 h and refluxed at Then 5 mmol of tert-butyl hydroperoxide (TBHP) was added
8
6
0 ºC for another 8 h. Then the solid was collected and dried at drop-wise under vigorous stirring. After a desired time, the
0 ºC for 8 h, and the modified SBA-15 was obtained.
catalyst was collected and the liquid phase was analyzed by gas
chro-matography-mass spectrometry (HP-5 column, Ar carrier
gas, 200 ºC).
2
.3. Preparation of CuO-x NiO/SBA-15 composites.
To confirm the wider applicability of our catalyst, different
olefins (trans-stilbene, cis-cyclooctene, trans-β-methylstyrene
and norbornene) were catalyzed using the same experimental
procedure.
CuO-NiO/SBA-15 composites were prepared via the ultrasonic
3
0
post-grafting method. Modified SBA-15 (0.2 g) was first
dried at 120 ºC for 4 h in a vacuum condition in order to
remove the adsorbed water. Then 20 mL Cu(NO ) ·3H O (1.61
3
2
2
g) and Ni(NO3)2 (0.97 g) ethanol solution (the total
concentration of the metal ions being 0.5 M) was injected into
the vacuum system under ultrasonic conditions. After 4 h of
ultrasonic impregnation, the solid was filtered and washed with
3
. Results and Discussion
3
.1. Synthesis of CuO-x NiO/SBA-15 composites.
ethanol several times. The obtained composite was dried at 60 CuO-x NiO/SBA-15 composites were prepared via ultrasonic
ºC overnight and calcined at 550 ºC for 4h with a heating ratio post-grafting method. The synthesis SBA-15 was first
of 2 ºC/min. The final CuO-NiO/SBA-15 composites were functionalized with -CH
and -NH on the external and internal
2
3
-
1
obtained and named as CuO-x NiO/SBA-15 (x represents the surfaces, respectively. The aborption peaks at around 2964 cm
-
1
molar ratio of Ni/Cu, according to the ICP analysis)
To investigate the influence of the amount of NiO, CuO- successful grafting of -CH
NiO/SBA-15 with higher NiO loading was prepared by using of -CH and aminopropyl groups are 8.2 wt% and 6.4 wt%,
and 2875 cm (Fig. S1) in the FT-IR study indicate the
and -NH on SBA-15 (the content
3
2
3
3
1
respectively (Fig. S2)). The modified SBA-15 was then mixed
2
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 7
PNl ee aws eJ do ou rnn oa tl ao df j uC sht emm ai rs gt ir ny s
Journal Name
with the precursor ethanol solution under ultrasonic conditions
ARTICLE
HRTEM images were determined to study the mVoierwphAroticlolegOynlionef
at room temperature for 4 h. Finally, the products CuO-x SBA-15 and CuO-x NiO/SBA-15 (x = 0, 0D.O1I7: 1a0n.1d0309./3C46)N(JF0i1g6.542E).
NiO/SBA-15 (x = 0, 0.17 and 0.34, x representing the molar The pure SBA-15 shows well defined 2D-hexagonal symmetry,
ratio of Ni/Cu, according to the ICP analysis) were obtained by and the pore diameter is 6.7 nm (Fig. 2a). After the metallic
calcinations at 550 ºC for 4 h. The Si-O vibration band in Si- oxides are loaded, the well-ordered arrays of mesoporous
-
1
OH around 960 cm in Fig. S3 declines and finally disappeares, channels of SBA-15 are still preserved (Fig. 2b-d). For
suggesting CuO loads dispersedly in the channels via bonding CuO/SBA-15, small amounts of large CuO particles are
with silanols.
observed on the exterior surface of SBA-15 (Fig. 2b). Compare
to the sample prepared using SBA-15 without modification as
support shows large amount of CuO particles on the exterior
surface of SBA-15 (Fig. S4), the modifications show an active
effect for the dispersion of CuO particles in the mesopores.
While NiO was added, the large CuO particles disappear
gradually and no nucleation of metallic oxide is observed (Fig.
2b-d), this suggests that the addition of small amount of NiO
makes CuO disperse uniformly in the mesoporous channels.
Fig. 1. Small-angle XRD patterns of SBA-15 and CuO-x NiO/SBA-15 (x = 0,
0
.17 and 0.34).
Small-angle XRD patterns of SBA-15 and CuO-x NiO/SBA-
15 (x = 0, 0.17 and 0.34) are shown in Fig. 1. SBA-15 shows a
very sharp d100 diffraction peak (at 2θ = 0.93º) together with
two less intense diffraction peaks d110 (at 2θ = 1.60º) and d200
(
at 2θ = 1.84º) reflections, indicating the well 2D hexagonal
3
2
structures of SBA-15. After the metallic oxides were
introduced (CuO-x NiO/SBA-15 (x = 0, 0.17 and 0.34)), the
intensity of the diffraction peaks becomes weaker and the
position changes to lower 2-Theta angle, suggesting the
successful introduction of the metal oxides into the mesoporous
Fig. 3. XRD patterns of (a) CuO/SBA-15, (b) CuO-0.17 NiO/SBA-15, (c)
CuO-0.34 NiO/SBA-15 and (d) NiO/SBA-15.
3
3-35
channels.
Fig. 3 presents the XRD patterns of CuO-x NiO/SBA-15 (x =
0, 0.17 and 0.34) and NiO/SBA-15. All the samples exhibit a
broad band at 23º, which corresponds to the amorphous
structure of silica. The CuO peaks for CuO/SBA-15 are found
at 35.2° and 38.5°, which correspond to the (002) and (111) of
tenorite copper oxide respectively [JCPDS card no. 02-1040].
No obvious peak belonging to NiO is observed in the
NiO/SBA-15 (the content of Ni is 5.33 wt%), and the HRTEM
image also shows no nucleation of NiO in the channels of SBA-
1
5 (Fig. S5). These results indicate the well dispersion of NiO
3
6
in the channels. While NiO was introduced into the
CuO/SBA-15, CuO-0.17 NiO/SBA-15 exhibits a decrease of
characteristic peaks of CuO (the content of Cu is 9.61 wt%),
and no characteristic peaks belonging to NiO can be observed.
While the content of Ni increases to 0.24 wt% (CuO-0.34
NiO/SBA-15), characteristic peaks of CuO almost disappeared
completely, indicating the well dispersal of CuO (the content of
Cu is 7.25 wt%). It is suggested that the presence of NiO causes
the redistribution of CuO, leading to an enhanced surface
3
5
content of CuO and the well dispersion of CuO nanoparticles.
Fig. 2. HRTEM images of (a) pure SBA-15, (b) CuO/SBA-15, (c)
CuO-0.17 NiO/SBA-15 and (d) CuO-0.34 NiO/SBA-15.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

PNl ee aws eJ do ou rnn oa tl ao df j uC sht emm ai rs gt ir ny s
Page 4 of 7
ARTICLE
Journal Name
View Article Online
DOI: 10.1039/C6NJ01654E
Fig. 5. XPS spectra of (a) Cu 2p3/2 for CuO/SBA-15 and CuO-0.34
NiO/SBA-15, (b) Ni 2p3/2 for CuO-0.34 NiO/SBA-15.
2
Fig. 4. N adsorption-desorption isotherms (a) and pore sizes distribution (b)
of SBA-15 and CuO-x NiO/SBA-15 (x = 0, 0.17 and 0.34).
The XPS analysis for a demonstration of the surface
chemical states of copper oxide and nickel oxide on CuO/SBA-
Table 1. Active phase content and texture properties of SBA-15 and
CuO-x NiO/SBA-15 (x = 0, 0.17 and 0.34).
15 and CuO-0.34 NiO/SBA-15 are shown in Fig. 5. The Cu
Sample
Cu
Ni
BET
V
3
p
D
p
content of CuO/SBA-15 determined by XPS is 9.8 wt%, which
is slightly lower than the ICP result (10.3 wt%), and the Cu and
Ni content of CuO-0.34 NiO/SBA-15 are 13.0 wt% and 1.0
wt%, respectively, which are both higher than the analysis by
ICP (Cu: 7.25 wt%, Ni: 0.24 wt%). These suggest that the
presence of NiO leads to an enhanced surface content of CuO.
A feature at 935.0 eV belonging to Cu 2p3/2 appears on
CuO/SBA-15, while it shifts to 934.1 eV on CuO-0.34
2
-1
-1
(
wt%) (wt%) (m g ) (cm g ) (nm)
SBA-15
-
-
836.4
444.5
431.8
389.0
0.89
0.57
0.54
0.57
6.63
6.60
6.39
6.59
CuO/SBA-15
10.3
9.61
7.25
-
CuO-0.17 NiO/SBA-15
CuO-0.34 NiO/SBA-15
0.16
0.24
N2 adsorption-desorption isotherms and the pore sizes NiO/SBA-15 (Fig. 5a). Meanwhile, the XPS spectrum of Ni
distribution of SBA-15 and CuO-x NiO/SBA-15 (x = 0, 0.17 2p3/2 for CuO-0.34 NiO/SBA-15 at 857.8 eV (Fig. 5b), typical
2
5
and 0.34) are shown in Fig. 4. All CuO-x NiO-loaded samples at 852.6 eV for bulk NiO , is observed, indicating some
exhibit typical type IV for mesoporous structure with H1 interaction between copper and nickel.
hysteresis loops (Fig. 4a), indicating the preservation of ordered
mesoporous structure after modifications and incorporating 3.2. Catalytic properties.
3
7
metallic oxide nanoparticles into the channels. The pore sizes
distribution calculated by the BJH method of all the samples are
showed in Fig. 4b. It can be observed that the desorption pores
diameters (Mode) of all composite samples are slightly lower
than that of pure SBA-15 (Fig. 4b). The texture properties of
the SBA-15 and CuO-x NiO/SBA-15 (x = 0, 0.17 and 0.34) are
shown in Table 1. After introducing CuO into the mesopore, the
pore size distribution calculated by the BJH method decreases
from 6.63 nm for SBA-15 to 6.60 nm for CuO/SBA-15, which
is larger than those containing CuO-x NiO in the channels. This
suggests that the CuO/SBA-15 with some large CuO particles
on the exterior surface of SBA-15 leads to a larger pore size
distribution. While the NiO was added, the large CuO particles
was dispersed into the channels and caused the decrease of pore
size to 6.39 nm for CuO-0.17 NiO/SBA-15. With the increase
of the amount of NiO, the dispersion of metallic oxide in the
channels leads to the increase of pore size to 6.59 nm for CuO-
The catalytic activities of CuO-x NiO/SBA-15 (x = 0, 0.17 and
.34) were evacuated by the epoxidation of styrene at 80 ºC
using TBHP as the oxidant and acetonitrile as the solvent
Table 2). CuO/SBA-15 and NiO/SBA-15 show low activity for
0
(
this reaction (Table 2, entry 4 and 5), but the introduction of
NiO (CuO-0.17 NiO/SBA-15) significantly enhances the
conversion of styrene (73.6%) and the selectivity for styrene
epoxide (83.2%) (Table 2, entry 6), demonstrating a clear
synergistic effect for the NiO-promoted CuO system as
compared with the monometallic species. In addition, with the
increase of the introduced amount of NiO to 0.34 mol%, the
conversion of styrene and selectivity for styrene epoxide
increase to 86.2% and 86.3%, respectively, while the physical
mixture of NiO/SBA-15 and CuO/SBA-15 shows no obvious
enhancement (Table 2, entry 9). Moreover, further increase of
the loading amount of NiO does not enhance the conversion of
styrene and selectivity for styrene epoxide (Table 2, entry 10).
0
.34 NiO/SBA-15. The BET specific surface area decrease
2
-1
2
-1
When small amounts of Na CO were introduced, the
2 3
conversion of styrene reached 100% and the selectivity for
styrene epoxide is 92.3% (Table 2, entry 8). By comparison,
from 836.4 m
g
for pure SBA-15 to 444.5 m
g
for
2
-1
CuO/SBA-15, to 431.8 m g for CuO-0.17 NiO/SBA-15, and
to 389.0 m g for CuO-0.34 NiO/SBA-15, respectively. In
parallel, the total pore volume decreases from 0.89 cm g for
SBA-15 to 0.57 cm g for CuO/SBA-15, to 0.54 cm g for
2
-1
3
-1
bare Na
entry 2). This should be due to the Na
radicals on CuO-NiO nanoparticles surface and enhancing the
2
CO
3
shows a little active for the reaction (Table 2,
3
-1
3
-1
2
CO reacting with the
3
3
-1
CuO-0.17 NiO/SBA-15, and 0.57 cm
g
for CuO-0.34
3
8
selectivity of styrene epoxide.
NiO/SBA-15, respectively. These may be due to some blocking
of the porosity after incorporation of metallic oxides.
4
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 5 of 7
PNl ee aws eJ do ou rnn oa tl ao df j uC sht emm ai rs gt ir ny s
Journal Name
ARTICLE
Table 2. Comparison of catalytic activity for the epoxidation of After certain times, cis-cyclooctene gives an 84.0%ViewcoArntivcleerOsniloinne
DOI: 10.1039/C6NJ01654E
styrene with different as-synthesized catalysts.
and 90.3% selectivity to epoxycyclooctane, and norbornene
shows a desired epoxide in 81.6% yield. Meanwhile, other
olefins, such as trans-β-methylstyrene and trans-stilbene have
higher epoxide in >99% yield. The reactivity trend (trans-
stilbene
>
trans-β-methylstyrene
>
norbornene
>
cis-
cyclooctene) indicates the effect of electron-donating groups. It
is suggested that substrates with electron-donating are absorbed
on the vacant coordination site on the metal oxide surface easily,
3
8
which makes the double bonds more reactive.
Reaction condition: catalyst containing 0.0129 mmol of CuO, 3 mmol of
styrene and 5 mmol of TBHP was stirred in 5 ml of acetonitrile at 80 ºC for
6
h, and nitrobenzene was used as the internal standard.
Scheme 1. The possible mechanism of the reaction pathways of styrene.
The stability and cycle performance of the catalyst was
Based on the above research, the possible mechanism of the
reaction pathways of olefins is proposed (Scheme 1). During
the catalytic process, the TBHP and substrate are absorbed into
the channels, and the adsorbed TBHP is preferentially located
on the metal oxide surface, which tends to form peroxidic
groups and radicals. The formed peroxidic groups react with the
neighboring adsorbed styrene molecules, and insert themselves
between the secondary carbons to form the oxametallacycle,
and then rearrange to form styrene oxide, while the formed
investigated. With the CuO-0.34 NiO/SBA-15 catalyst (added
Na CO into the reaction), the reaction was stopped after 6 h,
2
3
and the catalyst was collected and reused (Fig. 6a). The
recycling results show that the conversion rate maintained at
00% and selectivity of styrene oxide is 86% after cycled 5
times. Furthermore, the catalyst was filtered after 3h reaction,
and the liquid phase continued for another 3h, and the
conversion shows a slight increase in the absence of catalyst
1
3
9
(
Fig. 6b). These results show that the catalyst CuO-0.34
NiO/SBA-15 is stable and reusable.
radicals attack the oxametallacycle to get benzaldehyde. The
addition of Na CO , as a hydroxyl radical scavenger, enhances
2
3
both of the conversion of styrene and selectivity for styrene
epoxide. This suggests that the two pathways occur at the same
time, and the reaction speed of the epoxidation process is faster.
4
. Conclusions
In this paper, NiO promoted CuO-NiO/SBA-15 composites
were synthesized using the ultrasonic post-grafting method.
With the assistance of -NH2 groups, the precursors were
Fig. 6. (a) Recycling results for styrene epoxidation for CuO-0.34 NiO/SBA- absorbed into the mesoporous channels easily under ultrasonic
1
2 3
5 with Na CO added, and (b) leaching experiment.
conditions. The bi-metallic oxides are well-dispersed in very
small sizes in the mesoporous channels, and the presence of
Table 3. Comparison of the catalytic activity for olefin
2+
2+
Ni enhances the surface segregation of Cu , improving the
dispersion of CuO nanoparticles. The electron transfer that
occurs between the two metals oxide and good dispersion of
active components improve the overall selective epoxidation of
olefin with a remarkably high selectivity. In particular, the
CuO-0.34 NiO/SBA-15 shows 100% of conversion and 92.3%
selectivity for styrene oxide with the addition of Na CO .
epoxidation with CuO-0.34 NiO/SBA-15 as catalyst.
2
3
Acknowledgements
In order to investigate the range of adaptability of the CuO- We are grateful to the Co-building Special Project of Beijing
0
.34 NiO/SBA-15 catalyst, different olefins including cis-
Municipal Education 111 Project (No. B13004) for financial
support of this work.
cyclooctene, norbornene, trans-β-methylstyrene and trans-
stilbene were selected, and the results are shown in Table 3.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

PNl ee aws eJ do ou rnn oa tl ao df j uC sht emm ai rs gt ir ny s
Page 6 of 7
ARTICLE
Journal Name
3
6 C. Huang, Y. C. Chung and M. R. Liou, JournalVioewf AHrtaiczlearOdnoliunes
Notes and references
Materials, 1996, 45, 265.
DOI: 10.1039/C6NJ01654E
‡
Electronic Supplementary Information (ESI) available: [FT-IR, 37 M. Kruk and M. Jaroniec, Chem. Mater., 2001, 13, 3169.
TGA and HRTEM of CuO-x NiO/SBA-15].
38 Y. Yang, J. Ma, Q. Qin and X. J. Zhai, J. Mol. Catal. A: Chem., 2007,
1
2
3
4
5
J. Hu, J. Phys. Chem. C, 2013, 117, 16005.
276, 41.
B. Singh and A. K. Sinha, J. Mater. Chem. A, 2014,
2
, 1930.
39 R. A. Sheldon, Rec. Trav. Chim. Pays-Ba, 1973, 92, 253.
40 L. Zhou and R. J. Madix, J. Phys. Chem. C, 2008, 112, 4725.
A. Marimuthu, J. W. Zhang and S. Linic, Science, 2013, 339, 1590.
R. R. Sever and T. W. Root, J. Phys. Chem. B, 2003, 107, 4090.
A. Toshimitsu, H. Abe, C. Hirosawa and S. Tanimoto, J. Chem. Soc.
Chem. Commun., 1992, 284.
6
Y. Niibo, T. Nakata, J. Otera and H. Nozaki, ChemInform, 1991,
16, 22.
7
8
M. Chini, P. Crotti and F. Macchia, J. Org. Chem., 1991, 56, 5939.
Y. Yang, Q. Zhang, T. Shishido and K. Takehira, J. Catal., 2002, 209
,
1
86.
9
T. J. Terry and P. Stack, J. Am. Chem. Soc., 2008, 130, 4945.
1
1
1
1
0 K. Weissermel and H. J. Arpe, Industrial Organic Chemistry, 3rd ed.;
VCH: Weinheim, Germany, 1997.
1 V. Hulea and E. Dumitriu, Applied Catalysis A: General, 2004, 277
9.
,
9
2 M. Selvaraj, S. W. Song and S. Kawi, Microporous Mesoporous
Mater., 2008, 110, 472.
3 N. Anand, K. H. P. Reddy, V. Swapna, K. S. R. Rao and D. R. Burri,
Microporous Mesoporous Mater., 2011, 143, 132.
1
1
4 Y. Luo and J. Lin, Microporous Mesoporous Mater., 2005, 86, 23.
5 Y. Jin, P. J. Wang, D. H. Yin, J. F. Liu, H. Y. Qiu and N. Y. Yu,
Microporous Mesoporous Mater., 2008, 111, 569.
1
6 Y. H. Tang, M. Yang, W. J. Dong, L. Tan, X. W. Zhang, P. Zhao, C.
H. Peng and G. Wang, Microporous Mesoporous Mater., 2015, 215
99.
,
1
1
1
1
2
2
2
2
2
2
7 L. P. Xu, S. Sithambaram, Y. S. Zhang, C. H. Chen, L. Jin, R. Joesten
and S. L. Suib, Chem. Mater., 2009, 21, 1253.
8 G. H. Qiu, S. Dharmarathna, Y. S. Zhang, N. Opembe, H. Huang and
S. L. Suib, J. Phys. Chem. C, 2012, 116, 468.
9 V. R. Choudhary, R. Jha, N. K. Chaudhari and P. Jana, Catal.
Commun., 2007, 8, 1556.
0 C. Q. Chen, J. Qu, C. Y. Cao, F. Niu and W. G. Song, J. Mater.
Chem., 2011, 21, 5774.
1 A. Miller, B. Zohour, A. Seubsai, D. Noon and S. Senkan, Ind. Eng.
Chem. Res., 2013, 52, 9551.
2 N. Scotti, N. Ravasio, F. Zaccheria, R. Psaro, C. Evangelisti, Chem.
Commun.
3 Z. M. Ye, L. Hu, J. Jiang, J. X. Tang, X. Q. Cao and H. W. Gu, Catal.
Sci. Technol., 2012, , 1146.
4 X. W. Zhang, G. Wang, M. Yang, Y. Luan, W. J. Dong, R. Dang, H.
Y. Gao and J. Yu, Catal. Sci. Technol., 2014, , 3082.
, 2013, 49, 1957.
2
4
5 A. Ungureanu, B. Dragoi, A. Chirieac, C. Ciotonea, S. Royer, D.
Duprez, A. S. Mamede and E. Dumitriu, ACS Appl. Mater. Interfaces,
2
013,
5, 3010.
2
6 C. L. Carnes, J. Stipp and K. J. Klabunde, Langmuir, 2002, 18, 1352.
2
7 G. Ertl, R. Hierl, H. Knözinger, N. Thiele and H. P. Urbach, Appl.
Surf. Sci., 1980, , 49.
5
2
2
8 R. Hierl, H. Knözinger and H. P. Urbach, J. Catal., 1981, 69, 475.
9 X. B. Huang, M. Yang, G. Wang and X. X. Zhang, Microporous
Mesoporous Mater., 2011, 144, 171.
3
3
0 X. W. Zhang, N. Huang, G. Wang, W. J. Dong, M. Yang, Y. Luan
and Z. Shi, Microporous Mesoporous Mater., 2013, 177, 47.
1 X. B. Huang, W. J. Dong, G. Wang, M. Yang, L. Tan, Y. H. Feng
and X. X. Zhang, Journal of Colloid and Interface Science, 2011, 359
,
4
0.
2 J. Han, P. Fang, W. J. Jiang, L. Y. Li and R. Guo, Langmuir, 2012,
, 4768.
3
2
8
3
3
X. D. Zhang, Z. P. Qu, X. Y. Li, Q. D. Zhao, X. Zhang and X. Quan,
Mater Lett., 2011, 65, 1892.
3
3
4 P. V. Adhyapak, P. Karandikar, K. Vijayamohanan, A. A. Athawale
and A. J. Chandwadkar. Mater Lett., 2004, 58, 1168.
5 J. Blanco, P. Avila, S. Suárez, M. Yates, J. A. Martin, L. Marzo and
C. Knapp, Chemical Engineering Journal, 2004, 97, 1.
6
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 7 of 7
New Journal of Chemistry
View Article Online
DOI: 10.1039/C6NJ01654E
NiO promoted the well dispersion of CuO in the CuO-NiO/SBA-15 composites, which showed
high activity for the epoxidation of olefins.