全 文 ：书Article ID:1001-3555(2012)03-0216-09
Received date:2011-12-21;Revised date:2012-04-26．
Foundation item:The project was supported by the National Natural Science Foundation of China (200863009，U1033603) ，Natural Science Founda-
tion of Yunnan Pro-vince (2008CD065) ，Specialized Research Fund for the Doctoral Program of Higher Education and Program for Innovative Research
Team (in Science and Technology)in University of Yunnan Province (IRTSTYN) ，Science Research Fund of Department of Education of Yunnan Prov-
ince (09Y0462)．
Biography:QIN Yun，born in 1960，Bachelor of Science，Associate professor．
* Corresponding author:Tel:+ 86 － 871 － 5031567;Fax:+ 86 － 871 － 5031567;Email:jqwang@ ynu． edu． cn (J． Wang)．
Synthesis of Cobalt Doped Mesoporous Silica with high Cyclohexanone
Selectivity for Catalytic Oxidation of Cyclohexane by the wild
Sugarcane-grass Stems Bio-template Route
QIN Yun1，2，YAO Wen-hua1，2，LI Jun-jie1，ZHENG Kai1，ZHANG Xin1，
WANG Wei1* ，WANG Jia-qiang1*
(1． Department of Applied Chemistry，Key Laboratory of Medicinal Chemistry for Natural Resource，Ministry
of Education，Yunnan University，Kunming 650091，China;
2． Department of Resources and Environmental，Baoshan College，Baoshan 678000，China)
Abstract:Cobalt doped mesoporous silica (M-Co /SiO2)was synthesized by using wild sugarcane-grass (Erianthus rockii)
stems as template and used for the oxidation of cyclohexane． The catalyst was characterized by a combination of various
physicochemical techniques，such as X-ray diffraction，N2physisorption，diffuse reflectance UV-vis，FT-IR，Scanning elec-
tron microscopy． The XRD and N2physisorption results indicated that the catalyst was a mesoporous structure material that
cobalt oxides were highly dispersed on the surface of the catalyst． The UV-vis result indicated that the presence of both
Co2 + and Co3 + ． The catalytic oxidation of cyclohexane results exhibited high product (cyclohexanone) selectivity
(76． 7%)and reasonable substrate conversion (71． 0%)． The recycling experiment indicated that the catalyst can be
reused three times with catalytic activity changed little．
Key words:cobalt doped mesoporous silica;biotemplate;wild sugarcane-grass stems;characterization;selective oxidation
of cyclohexane;cyclohexanone
CLC number:O643． 3 Document code:A
Biological templates have attracted considerable at-
tention for the syntheses of inorganic materials in the re-
cent several years［1］，because they are generally per-
formed under mild conditions，it is energy-conserving，
green，and has little requirement for equipments［2 － 8］．
Moreover，most natural templates and building blocks
can be harvested in large amounts at low costs，thus bi-
omorphic assembly is cheap compared with conventional
assembly methods to form nanostructures［7］． However，
the catalytic (except for few photocatalytic)properties
of these materials were seldom explored． For example，
biomorphic self-supporting MFI-type zeolite frameworks
with hierarchical porosity and complex architecture were
prepared using a biological template (Luffa sponge)as
macroscale sacrificial structure builder［2］． Interestingly，
the as-synthesized biomimetic ZSM-5 replica showed
catalytic activity for cracking of n-hexane with no need
for ion-exchange． In our group cobalt doped porous
titania-silica was synthesized by using rice husks as both
silicon source and template and it presented good pro-
duct (4-pyridinecarboxylic acid)selectivity (91%)and
high substrate conversion rate (96%)for the catalytic
oxidation of 4-methyl pyridine［8］．
Cyclohexane oxidation is an important commercial
第 26 卷 第 3 期 分 子 催 化 Vol． 26，No． 3
2012 年 6 月 JOURNAL OF MOLECULAR CATALYSIS(CHINA) Jun． 2012
DOI:10.16084/j.cnki.issn1001-3555.2012.03.009
reaction to produce cyclohexanone，which is a starting
material used in the production of nylon-6 and nylon-
66［9，10］． Although homogeneous systems have been
used for these processes，recent articles have illustra-
ted the use of mesoporous solids including the titanosil-
icate TS-1，transition metal (Cr，V，Co，Ti，etc．)
doped MCM-41［11］ and Mo-MCM-41［12］ for the selec-
tive oxidation of this hydrocarbon． In particular，Sak-
thivel and Selvam used Cr-MCM-41 catalyst for oxidi-
zing cyclohexane，giving a conversion rate of 98． 9%
with a selectivity of 92． 9% towards cyclohexanol．［13］
We showed that cerium doped MCM-41 has achieved
very good conversions of 94． 6% oxidizing cyclohexane
and 82． 4% cyclohexanol［14］． Recently，Ag-substitu-
ted anatase phase nano-TiO2 have been synthesized and
used for the selective photocatalytic oxidation of cyclo-
hexane to cyclohexanone［15］． More recently，in our
group cobalt doped SBA-3 was synthesized and found
that it exhibited high cyclohexane conversion
(91． 6%)and reasonable product (cyclohexanone)
selectivity (64． 3%)［16］． Interestingly，incorporation
of 4-(methylamino)benzoic acid together with chromi-
um into the rice husk silica framework gave 100% con-
version of cyclohexane in a much shorter time［17］． Bio-
mimetic iron(III)complexes immobilized within nano-
reactors of Al-MCM-41 exhibited excellent activity for
the production of cyclohexanone［18］． Although consi-
derable efforts have been made，cyclohexane oxidation
continues to be a challenge［19］．
Wild sugarcane-grass stems (Erianthus rockii)is
a drought and cold tolerant wild relative of sugar cane
from China that is currently being used in sugar cane
introgression programs［20］． However，there is no report
on using wild sugarcane-grass stems as template so far
as we know． Herein，it was used as template or mac-
roscale sacrificial structure builder［2］ to synthesize co-
balt doped mesoporous silica (M-Co /SiO2)which was
used as a catalyst for the catalytic oxidation of cyclo-
hexane．
1 Experimental Section
1． 1 Materials
Erianthus rockii samples were randomly collected
from a suburb house of Kunming (latitude:102． 7 °N;
longitude:25 °E;altitude:1 900 m) ，Yunnan Pro-
vince，China． Other chemical reagents，such as，tet-
raethyl orthosilicate (TEOS) ，2-propanol，HCl，cyclo-
hexane，cyclohexanone，cyclohexanol，acetic acid and
aqueous hydrogen peroxide (H2 O2，30%)were of
analytical grades and used as received．
1． 2 Synthesis of M-Co /SiO2
The stems of Erianthus rockii were washed tho-
roughly with water to remove the adhering soil and
dust． Then they were cut and immersed in 1 mol L －1
HCl solution at 353 K for 48 h to eliminate metallic im-
purities and washed with distilled water until no Cl-was
detected． The stems were further rinsed in 2-propanol
repeatedly until they were completely dehydrated．
Then 20 mL(0． 09 mol)TEOS was dissolved in 50 mL
ethanol and the dehydrated Erianthus rockii stems were
simply dipped into this solution． The samples were
shaken in an ultrasonic bath for 3 h to release the air
bubbles emanating from the Erianthus rockii stems and
allow the solution containing TEOS to enter the stems
more easily． Subsequently，the cobalt precursor (Co
(NO3)2 6H2 O)was introduced with Si /Co (molar)
ratio of 50． The samples were shaken in an ultrasonic
bath for another 3 h and then placed quietly for 12 h．
The above solution was added with 10 mL ammonia．
After a desired period of time，Erianthus rockii stems
were filtered out and washed with distilled water to pH
7． 5． The treated Erianthus rockii stems were dried in
air at room temperature and calcined at 823． 15 K for 8
h in an oven in air to burn off the organics． After natu-
rally cooling to room temperature， a laurel-green
product，M-Co /SiO2 was obtained．
1． 3 Characterizations
X-ray powder diffraction (XRD) experiments
were conducted on a D /max-3B spectrometer with Cu
Kα radiation，and scans were made in the 2θ range
10° ～ 100° with a scan rate of 10° /min (wide angle
diffraction)． Pore size distributions，BET surface are-
as，and pore volumes were measured by nitrogen ad-
sorption /desorption using ASAP2020 gas sorption ana-
lyzer (Micromeritics Crop)． Prior to the analysis，the
samples were degassed at 150 ℃ for 10 h． UV-vis dif-
712第 3 期 秦云等:以野生滇蔗茅为生物模板剂合成 Co掺杂的介孔 SiO2 高选择性催化氧化环己烷制备环己酮
fuse reflectance spectra were measured at room temper-
ature in air on a SHIMADZU UV-2401PC photometer
over the range from 200 to 800 nm． FT-IR measure-
ments were performed on a Thermo Nicolet 8 700 in-
strument． Potassium bromide pellets containing 0． 5%
of the catalyst were used in FT-IR experiments and 32
scans were accumulated for each spectrum in transmis-
sion，at a spectral resolution of 4 cm －1 ． The spectrum
of dry KBr was taken for background subtraction．
Scanning electron microscopy (SEM) images were
taken on a FEIQuanta200FEG microscope at an accel-
erating voltage of 15 kV with the pressure in the sample
chamber of 1 Torr． Inductively coupled plasma atomic
emission spectrometry (ICP AES;Labtam Plasma Lab
8 440)analysis was used to determine the content of
metal in the catalysts．
1． 4 Oxidation of cyclohexane
The oxidation reactions were carried out at the at-
mospheric pressure as follows:The catalyst (50 mg) ，
cyclohexane (AR grade，750 mg)and 15 mL of solvent
(acetic acid，ethyl acetate，acetonitrile and ethanol
were used as received without further purification)
were added successively into a temperature-controlled，
round bottom，two-necked-flask having a reflux con-
denser． The aqueous H2 O2(30% solution，approxi-
mately 5 mL)was added dropwise after the reaction
mixture was heated to the set temperature． The reaction
mixture was filtered under reduced pressure after the
set time． The residue was extracted with diethyl ether．
Anhydrous Na2 CO3(AR grade)was used to remove
more water from the extracted organic phase． Then the
mixture was filtered under reduced pressure and
washed again by diethyl ether． The obtained products
were analyzed by gas chromatography (Shimadzu GC-
14C)with a packed column (3 m × 2 mm，10%
PEG 20 M /101)and a flame ionization (FID)detec-
tor． Reference substances were used for the identifica-
tion of the products．
2 Results and Discussion
2． 1 The characterization of M-Co /SiO2
Fig． 1 shows wide-angle X-ray diffraction (XRD)
patterns of M-Co /SiO2 measured at 2θ of 10° ～ 100°．
Wide-angle XRD results showed M-Co /SiO2 had the
characteristic of amorphous silica phase which is con-
sistent with the observation of FT-IR spectra． It is worth
noting that no distinct diffractions corresponding to any
crystalline cobalt oxides are observed at higher angles．
This implies that cobalt oxides were highly dispersed on
the surface of the catalyst． Similar observations have
been reported for Co-MCM-41 and Co-SBA-3［15，16］．
Fig． 1 XRD patern of M-Co /SiO2
The N2 adsorption /desorption isotherms of M-Co /
SiO2 are shown in Fig． 2． The isotherm of M-Co /SiO2
can be classified as type IV according to the IUPAC
convention and is typical of mesoporous structure of
prepared material． This is also supported by the big
average pore diameter (12． 6 nm) ，BET surface areas
(438 m2·g －1) ，and pore volume (1． 5 cm3·g －1)．
In addition，the BJH pore size distribution of M-Co /
SiO2(inset in Fig． 2)shows one primary pore size dis-
tribution in the mesopores region between 2． 1 and 45
nm which indicates that the catalyst has irregular pore
channels．
The diffuse reflectance UV-vis spectrum of M-Co /
SiO2 is given in Fig． 3． The absorption at 400 nm indi-
cates the presence of Co3 + and the absorption at 500 ～
800 nm can be attributed to the presence of both Co2 +
and Co3 +［21 － 23］．
The FT-IR spectra of M-Co /SiO2 and Co-MCM-41
was recorded between 400 cm －1 and 4 000 cm －1 in
transmission mode and shown in Fig． 4． Obviously，
they are very similar． No bands associated with orga-
812 分 子 催 化 第 26 卷
Fig． 2 Nitrogen adsorption /desorption isotherm and BJH pore
size distribution of M-Co /SiO2
Fig． 3 UV-vis spectra of M-Co /SiO2
nics are observed． The bands at ca． 1 090 and ca．
790 cm －1 are due to the asymmetric and symmetric Si-
O-Si stretching modes，respectively［24，25］． However，
after the incorporation of Co into the framework of
SiO2，the shift of the band from 1 080 to 1 105 cm
－1
was observed． The shift is bigger than the incorporation
of Co into the framework of MCM-41． In the hydroxyl
region (3 000 ～ 3 500 cm －1) ，the broad bands are ob-
served at ca． 3 400 and 3 450 cm －1 for both Co-MCM-
41 and M-Co /SiO2
［26，27］．
SEM image presented in Fig． 5 shows the morpho-
logy of M-Co /SiO2 ． The hierarchical and complex ar-
chitecture including cubic，cylindrical and also some
irregular shapes with random size at 35 ～ 55 μm was
obtained．
The X Ray Fluorescence(XRF)measurement of
Fig． 4 FT-IR spectra of (a)M-Co /SiO2 and(b)Co-MCM-41
Fig． 5 SEM of M-Co /SiO2
M-Co /SiO2 revealed that molar ratio of Co /Si (molar)
ratio in the catalysts is 0． 007，much lower than that of
0． 02 calculated by the amount of Co(NO3)2·6H2 O
and TEOS in the preparing process． This could be
caused by the loss of cobalt ions during synthesis．
2． 2 Catalytic performance
Using cobalt doped mesoporous silica prepared by
above process as a catalyst，it was found that the main
products detected are cyclohexanone and cyclohexanol
for the oxidation of cyclohexane． Little cyclohexyl ace-
tate could be detected as by-products． Cyclohexyl ace-
tate was possibly produced due to the termination reac-
tion between unreacted cyclohexyl and acetoxy radicals
and /or by a possible reaction of cyclohexanol with ex-
cess acetic acid in the presence of the catalyst［28］． The
effects of catalysts on the cyclohexane oxidation are
shown in Table 1． It is seen that M-Co /SiO2 has the
912第 3 期 秦云等:以野生滇蔗茅为生物模板剂合成 Co掺杂的介孔 SiO2 高选择性催化氧化环己烷制备环己酮
reasonable conversion rate of 71． 0%，which is signifi-
cantly higher than Co-SBA-15，but lower than Co-HM-
CM-41［29］ and Co-SBA-3． However，M-Co /SiO2 has
the highest selectivity of (76． 7%)compared with Co-
HMCM-41，Co-SBA-3 and Co-SBA-15 reported in
ref［16］． Although Co- HMCM-41，Co-SBA-3 and Co-
SBA-15 have much bigger surface area than M-Co /
SiO2 synthesized by using Erianthus rockii stems as
template，they are less selectivity compared with M-
Co /SiO2 ． This may imply that pore size would play
more important role since the pore size of M-Co /SiO2
(12． 6 nm)is much bigger than Co-HMCM-41，Co-
SBA-3 and Co-SBA-15 whose pore size is 2． 8，3． 6，
4． 5 nm，respectively．
Table 1 Effects of catalysts on the cyclohexane reactiona
Catalysts
Conversion
(%)
TON
Selectivity (%)
Cyclohexanone Cyclohexanol By-product
Co /SBA-316 91． 6 500． 3 64． 3 35． 6 0． 1b
Co /SBA-1516 42． 8 233． 8 68． 0 31． 8 0． 2
Co-HMCM-4129c 80． 8 91． 0 14． 2 76． 1 9． 7
M-Co /SiO2 71． 0 387． 8 76． 7 21． 2 2． 1
aReaction conditions:reaction time，10 h;catalyst，50 mg;reaction temperature，373 K;b Cyclohexyl acetate;c Reaction
conditions:reaction time，12 h;catalyst，400 mg;reaction temperature，373 K
TON，turn over number (millimole of oxidized products per millimole of metal in the catalyst)．
The high efficiency of M-Co /SiO2 may also be ex-
plained as follows:Firstly，the big surface area，high
thermal stability and excellent mechanical strength of
M-Co /SiO2 makes M-Co /SiO2 a highly effective cata-
lyst since the intradiffusion resistance is minimized and
the efficiency of selective oxidation is enhanced．
Secondly，the results obtained from XRD，FT-IR and
diffuse reflectance UV-vis spectroscopy indicate that
both Co2 + and Co3 + are well dispersed on the silica
surfaces and is more like that of Co-SBA-3［16］． These
factors can also modify the efficiency． Thirdly，since it
also exhibited higher selectivity than Co-SBA-3 and
Co-SBA-15 reported in ref．［16］，its hierarchical poro-
sity and complex architecture including cubic，cylindri-
cal and also some irregular shapes has an important im-
pact on the catalytic activity． This should also help to
overcome the intradiffusional resistance in a typical me-
soporous material．
2． 3 Effect of reaction temperature
As shown in Fig． 6，the catalytic performances
were affected by temperature． The conversion of cyclo-
hexane increased by increasing the reaction tempera-
ture and passed through a maximum at 373 K while the
Fig． 6 Effect of reaction temperature on the conversion
and selectivity over M-Co /SiO2
( a)Conversion of cyclohexane; (b)Selectivity of cyclohexanone
(Reaction condition:750 mg cyclohexane，50 mg catalyst，
15 mL acetic acid，10 h reaction time)
selectivity to cyclohexanone increased． A further in-
crease in the reaction temperature resulted in decrease
both conversion and selectivity，probably owning to a
quicker decomposition of H2 O2 at higher temperature
which resulted in a relatively low activity［14］． Thus，
373 K was chosen as the suitable temperature for the
022 分 子 催 化 第 26 卷
oxidation of cyclohexane．
2． 4 Effect of reaction time
The effect of reaction time on cyclohexane oxida-
tion was also investigated and depicted in Fig． 7． It is
seen that the conversion of the cyclohexane increased
with time up to 12 h while the selectivity passed
through a maximum at 10 h，a further increase in the
reaction time resulted in slightly decrease in the selec-
Fig． 7 Effect of reaction time on the conversion and
selectivity over M-Co /SiO2
( a)Conversion of cyclohexane; (b)Selectivity of cyclohexanone
(Reaction condition:750 mg cyclohexane，50 mg catalyst，
15 mL acetic acid，373 K for reaction temperature)
tivity of cyclohexanone． Therefore，the optimum con-
version and selectivity could be achieved at about
10 h．
2． 5 Effect of solvents
The nature of solvents was known to have a major
influence on reaction kinetics and product conversion
in the oxidation of cyclohexane． Therefore，the effects
of various solvents on the reaction are summarized in
Table 2． Obviously，M-Co /SiO2 has the best perfor-
mance in acetic acid． This is due to possible partial
decomposition of H2O2 because it was reported that the
decomposition of H2O2 are faster in these solvent than
acetic acid［30］． Moreover，it has been reported that
acetic acid does not only act as a solvent，but also
serves as a good oxidizing agent because of the forma-
tion of the framework silica peroxy acetic acid complex
probably formed in the pores of cobalt doped meso-
porous silica，then it would be more hydrophobic and
stable， as compared with hydrogen peroxide［31］．
Therefore，a better interaction of this complex with
cyclohexane can be expected． In general，it is consi-
dered that acetic acid does not only facilitate homoge-
neity of the liquid phase，but also be responsible for
the increase in overall oxidation activity．
Table 2 Effects of solvents on the cyclohexane oxidationa
Solvents
Conversion
(%)
TON
Selectivity(%)
Cyclohexanone Cyclohexanol
Acetic acid 71． 0 387． 8 76． 7 21． 2
Ethanol 10． 8 59． 0 48． 3 51． 7
Ethyl acetate 10． 0 54． 6 67． 9 32． 1
Acetonitrile 13． 8 75． 4 22． 2 23． 0
aReaction conditions:reaction time，10 h;catalyst，50 mg;reaction temperature，boiling point of solvents，
except for acetic acid at 373 K
2． 6 Effect of Co /Si molar ratio
Table 3 showed the effect of cobalt content on the
reaction． It is seen that the cyclohexane conversion and
cyclohexanone selectivity increased with cobalt content
and that a maximum conversion was obtained at Co /Si
ratio of 1 /50． However，the observed decrease in cy-
clohexane conversion and cyclohexanone selectivity at
higher cobalt content (Co /Si = 1 /30)could be due to
the presence of excess amount of cobalt，which lead to
competent interaction of metal oxo-species with both al-
122第 3 期 秦云等:以野生滇蔗茅为生物模板剂合成 Co掺杂的介孔 SiO2 高选择性催化氧化环己烷制备环己酮
kylperoxy species and cyclohexane，thus inhibiting the
catalytic oxidation［32］．
Table 3 Effect of molar ratio of Co /Si the cyclohexane
oxidationa
Molar ratio
of Co /Si
Conversion
(%)
Selectivity(%)
Cyclohexanone Cyclohexanol
1:30 38． 3 58 42
1:50 71． 0 76． 7 21． 2
1:70 9． 1 17． 6 82． 4
a Reaction conditions:reaction time，10 h;catalyst，50
mg;reaction temperature，373 K
2． 7 The reusability and fast hot catalyst filtration
experiment
To check the stability and recycling ability as well
as leaching of cobalt ions from M-Co /SiO2 under reac-
tion conditions，recycling experiment were carried out
using acetic acid as solvent． The typical recycling pro-
cedure was as follows:after the initial reaction，the
catalyst was separated from the reaction mixture and
washed with acetone and dried at 363 K，followed by
the activation at 673 K for 4 h． The reaction was then
carried out on the recycled activated catalyst under the
optimum condition． The results are also summarized in
Table 4． The recycling experiment results indicated
that the catalyst can be reused three times with cataly-
tic activity changed little． These results indicate that
the catalyst is a stable．
Table 4 Recycling experiment of the catalyst under the
optimum conditiona
Recycling
times
Conversion
(%)
Selectivity(%)
Cyclohexanone Cyclohexanol
First 71． 0 76． 7 21． 2
Second 65． 1 75． 1 22． 6
Third 61． 7 70． 9 23． 9
aReaction conditions:reaction time，10 h;catalyst，
50 mg;reaction temperature，373 K
In order to prove whether M-Co /SiO2 is a hetero-
geneous one，experiments with fast hot catalyst filtra-
tion and studying the reactivity of the filtrate had been
done by a modified process as described in ref． ［33］:
50 mg catalyst，750 mg cyclohexane，10 mL HAc and a
certain amount of H2 O2 was stirred at the temperature
of 373 K for 1 h (conversion of cyclohexane was
0． 9%)． The observation was also well supported by
ICP-AES analysis of the filtrates obtained from the fast
hot catalyst filtration where negligible amount of leac-
hing of active cobalt ≤0． 002% ． These indicated that
the active component (cobalt)did not leach to the so-
lution and M-Co /SiO2was a heterogeneous catalyst．
3 Conclusions
It can be concluded that cobalt doped mesoporous
silica prepared by using Erianthus rockii stems as tem-
plate was an efficient and highly selective catalyst for
the oxidation of the cyclohexane to cyclohexanone un-
der relatively mild reaction conditions without adding
any initiator． Fast hot catalyst filtration experiment
proved that the catalyst acted as a heterogeneous one
and it can be reused once with almost the same activi-
ty． We believe that the synthetic strategy demonstrated
here could be extended to other mesoporous materials
and other plants． This could open up new uses for me-
soporous silica prepared by using biotemplates in highly
selective oxidations．
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322第 3 期 秦云等:以野生滇蔗茅为生物模板剂合成 Co掺杂的介孔 SiO2 高选择性催化氧化环己烷制备环己酮
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以野生滇蔗茅为生物模板剂合成 Co掺杂的介孔 SiO2
高选择性催化氧化环己烷制备环己酮
秦 云1，2，姚文华1，2，李俊杰1，郑 凯1，张 新1，王 伟1，* ，王家强1，*
(1． 云南大学 应用化学系 教育部自然资源药物化学重点实验室，云南 昆明 650091;
2． 保山学院 资源环境学院，云南 保山 678000)
摘 要:以野生滇蔗茅为生物模板剂合成 Co掺杂的介孔 SiO2催化氧化环己烷． 并用 X射线衍射、N2-物理吸附和解
吸附、紫外-可见光光度计、傅里叶红外光谱仪和扫描电镜对材料进行了表征． X 射线衍射、N2-物理吸附和解吸附
研究结果表明该材料为介孔材料且氧化钴高分散于介孔材料的表面． 紫外-可见光光谱表明钴离子以 Co2 +和Co3 +
的形态存在． 环己烷的催化氧化结果表明催化剂能高效催化环己烷(环己烷的转化率为 71． 0%)转化为环己酮(选
择性高达 76． 7%)． 催化剂的重复性试验表明该催化剂具有较高的稳定性，循环使用 3 次后，催化活性仅有微小
的改变．
关键词:Co掺杂介孔 SiO2;生物模板;选择性氧化;环己烷;环己酮
422 分 子 催 化 第 26 卷