lp
ina
ou, Fujian 350002, China
Cellulose nano-crystals (CNC)
repw
ouscryopoegr
hotocatewatesting oigmentcatalys [4,5].een re
ed from Tianjinhexahydrate washydroxide was
Contents lists available at ScienceDirect
journal homepage: www.el
Materials
Materials Letters 159 (2015)
218220http://dx.doi.org/10.1016/j.matlet.2015.06.103A CNC
suspension was prepared with 14.285 g of CNC (3.5%, w/w) dispersed
by ultrasonic treatment for 10 min. The ferric chlor-ide solution
(0.416 g ferric chloride hexahydrate dissolved in2.5 mL deionized
water) was added drop-by-drop into the CNC
0167-577X/& 2015 Elsevier B.V. All rights reserved.
n Corresponding authors at: Limerick Pulp and Paper Centre,
University of NewBrunswick, Canada, E3B 5A3. Fax: 1 506
4534767.
E-mail addresses: [email protected] (H.
Liang),[email protected] (K. Liu).resources [1417].Cellulose
nano-crystals (CNC) are rod-shaped cellulose crystals 2.2.
Synthesis of mesoporous -Fe2O3method is one of the most promising
methods for the synthesis ofinorganic nanomaterials, which utilizes
a prefabricated structureto form well-dened, ordered architecture.
In the past, a numberof scientically signicant template methods
have been reported[1013]. However, most of the templates cannot be
used for a wildrange of production due to their high cost for the
templates pre-paration. Today, Cellulose based materials, as a
template to be usedin the preparation of nanomaterials, is getting
an increase interestbecause of being one of the most abundant and
renewable natural
2. Experimental
2.1. Chemicals
Cellulose nano-crystals (CNC) were obtainHaojia Cellulose Co.,
Ltd., China. Ferric chloridepurchased from Sigma-Aldrich and
ammoniumfrom EMD, respectively.Fe2O3, including precipitation [6],
solgel method [7], hydro-thermal preparation [8] and template
synthesis [9]. The template
CNC in the general area of material science.Photo-catalytic
properties
1. Introduction
Recently, metal oxides used as pgrade organic pollutants from
wasattention [13]. -Fe2O3 is an interetential applications, for
example, pbents for water treatment. As a photoan extensive variety
of contaminant
Various synthetic methods have btalytic materials to de-r have
attracted muchne due to its wide po-s, catalysts and absor-st,
-Fe2O3 can degrade
ported to synthesize -
with their length of 100 nm to 12 m and width of 520 nm.They can
be extracted from natural sources including cotton, grassand wood.
CNC are promising nanoscale biomass materials due totheir renewable
nature, low density, and electric properties [17].
Nanoparticles prepared with solgel method has a uniform
sizedistribution [18].In this paper, a mesoporous -Fe2O3
materialswere prepared based on the solgel method using CNC as
templateand their catalytic property was determined under the
visible lightconditions. The objective was to further extend the
applications ofX-ray techniquesSynthesis of mesoporous -Fe2O3 via
sonano-crystals (CNC) as template and its
Hunan Liang a,b,n, Kai Liu b,c,n, Yonghao Ni b
a The College of Chemical Engineering, Northeast Dianli
University, Jilin, Jilin 132012, Chb Limerick Pulp and Paper
Centre, University of New Brunswick, Canada E3B 5A3c The College of
Materials Engineering, Fujian Agriculture and Forestry University,
Fuzh
a r t i c l e i n f o
Article history:Received 3 February 2015Received in revised
form19 April 2015Accepted 28 June 2015Available online 30 June
2015
Keywords:Mesoporous -Fe2O3Sol-gel preparation
a b s t r a c t
Mesoporous -Fe2O3 was pthe template. The samplesdicated that the
mesoporsuccessfully prepared. Thewas 47.26 m2 g1. The mescatalytic
activity for the dwithout CNC.ared based on the solgel method using
cellulose nano-crystals (CNC) asere characterized by SEM, TEM, XRD
and N2 adsorption. The results in--Fe2O3 samples with a predominant
pore diameter of 17.3 nm were
stalline size of -Fe2O3 samples was about 57 nm and specic
surface arearous -Fe2O3 prepared with CNC as the template exhibited
better photo-adation of methylene blue (MB) as compared to the
sample prepared
& 2015 Elsevier B.V. All rights reserved.gel methods using
cellulosehoto-catalytic properties
sevier.com/locate/matlet
Letters
suspension and vigorously stirred at 40 C for 10 min. Then,
theammonia solution was added for maintaining its pH at 10 and
thereaction was continued for 2 h. Subsequently, the mixture
washeated at 90 C and nally, the gel was formed. The resulting
gelmaterials was aged for 3 h, and then centrifuged and
washedseveral times. After that, the sample was dried at 100 C for
about12 h. The dried sample was calcined at 600 C for 2 h to obtain
the-Fe2O3. For comparing, the -Fe2O3 sample without CNC was
alsoprepared under otherwise the same condition.
2.3. Characterization
The morphology of the sample was characterized by scanning
prepared with CNC had a more uniform size distribution and
more
prepared with CNC and without CNC, respectively).The nitrogen
adsorption curve of sample prepared with CNC as
template was shown in Fig. 3. The isotherms can be classied
as
20 30 40 50 60 70 80
Inte
nsity
2 Theta (degree)
(b)012
104
110
113024
116
018214300
Fig. 2. XRD patterns of the prepared -Fe2O3. (a): Sample
prepared without CNC;(b): sample prepared with CNC as template.
0.0 0.2 0.4 0.6 0.8 1.00
20406080
100120140160180
0 10 20 30 40
500.000000.000010.000020.000030.000040.000050.000060.000070.000080.000090.00010
Dv
(d) (
cc/n
m/g
)
Diameter (nm)
Vol
ume
Ads
orbe
d (c
m3 g
-1)
P/P0
Adsorption Desorption
Fig. 3. Nitrogen adsorptiondesorption isothems (a) and pore size
distributioncurve (b, which is the inserted one) for the -Fe2O3
prepared with CNC as template.
H. Liang et al. / Materials Letters 159 (2015) 218220 219pore
distribution than the sample prepared without CNC. Fig. 1(c:without
CNC, d: with CNC) was the TEM image of the prepared -Fe2O3 sample.
It can be observed that the average particle sizes ofthe samples
prepared with CNC and without CNC were about55 nm and 65 nm,
respectively.
Fig. 2 presented the XRD patterns of the -Fe2O3 preparedwithout
and with NCC as template. The major diffraction peaks ofsamples
were consistent with the data of standard -Fe2O3
sample(JCPDS-84-0311). The results supported the conclusion that
both ofprepared samples were composed of high purity -Fe2O3.
Thecrystalline size of -Fe2O3 prepared with CNC and without
CNC,which were calculated from the XRD data by the
DebyeScherrerequation, were about 57 nm and 67 nm, respectively.
These resultswere in a good accordance with those from the TEM
analysis (theaverage particle sizes of about 55 nm and 65 nm for
the sampleselectron micrographs (SEM, JSM-6400, JEOL). The
particles sizeswere determined by transmission electron microscopy
(TEM,JEOL2010).The purity of samples was characterized by X-ray
dif-fraction (XRD) on a Bruker D8 Advance spectrometer. The
X-raysource was a sealed, 2.2 kW Cu X-ray tube. N2 adsorption
wasmeasured using specic surface area measurement (Quantachrome
Instruments, USA).
2.4. Photocatalysis
The photocatalytic activity of samples was conducted by
thedegradation of methylene blue (MB) in aqueous solution
usingvisible light (halogentungsten lamp 100 W) at ambient
tem-perature. The catalyst dosage was 0.05 g and the initial
con-centration of MB was 5 mg L1 of MB solution (50 mL).
3. Results and discussion
The morphology of prepared -Fe2O3 by SEM was showed inFig. 1(a:
without CNC, b: with CNC). It was seen that the -Fe2O3Fig. 1. SEM
(a, b: cross section) and TEM (c, d) images of the mesoporous
(a)-Fe2O3 sample (a, c: prepared without CNC; b, d: prepared with
CNC).
a kind of surface reaction, the higher surface area of the
-Fe2O3prepared with CNC as template would then be responsible for
theimproved performance in the photocatalytic degradation of
MB.
4. Conclusions
[6] H. Aono, H. Hirazawa, T. Naohara, T. Maehara, H. Kikkawa, Y.
Watanabe, Mater.Res. Bull. 40 (2005) 11261135.
0.9
1.0 (a) (b) (c)
H. Liang et al. / Materials Letters 159 (2015) 218220220Type IV
isotherm of the mesoporous materials [19], which wasrelated to
capillary condensation taking place in mesopores. Thepore size
distribution of -Fe2O3 nanoparticles was in the range of442 nm with
a predominant pore diameter of 17.3 nm. The widepore size
distribution might be due to the face that some of theCNC are
aggregated, which led to the different width of CNC. Forthis reason
the synthesized -Fe2O3 nanoparticles had a widerange of particle
size distribution.
The specic surface area and the total pore volume of
sampleprepared with CNC as template were 47.26 m2 g1 and0.26 cm3
g1, respectively, which are comparable with those ofthe -Fe2O3
prepared using anionic surfactant as template [20]and higher than
those of the sample prepared without CNC(31.1 m2 g1 and 0.19 cm3
g1, respectively). These results showed
0 30 60 90 120 150 1800.6
0.7
0.8C/C
0
Time (min)Fig. 4. Photocatalytic degradation rates of MB by the
prepared -Fe2O3 undervisible-light irradiation. (a): blank; (b):
the sample prepared without CNC; (c): thesample prepared with CNC
as template. C and C0 were the concentration of MBafter irradiation
in a selected time interval and initial concentration of
MB,respectively.that the mesoporosity was generated once the CNC
templateswere removed after calcination. Consequently, the specic
surfacearea and pore volume of the sample were increased.
The photocatalytic activity of the samples was evaluated
bymonitoring the degradation of methylene blue (MB) in
aqueoussolution under visible light. The MB concentration was
followed byan ultraviolet (UV)visible spectrometer at a wavelength
of660 nm, and a lower MB concentration represents more
photo-catalytic activity of the prepared -Fe2O3 samples. Fig. 4
presentedthe changes of relative concentration of MB as a function
of irra-diation time.
It was shown that the rate of MB degradation was slow in
theblank experiment (without the addition of mesoporous
catalyst),and only 19% of the initial concentration decreased
within180 min. In the presence of -Fe2O3 sample, however, the
de-gradation rate of MB increased obviously. The -Fe2O3
materialsprepared with CNC as template exhibited much improved
photo-catalytic activity than that prepared without CNC (38% vs
23%). As
Chem. Soc. 128 (2006) 1290512909.[11] M.R. Jones, K.D. Osberg,
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(2004) 5211-6.[13] A. Mitra, C. Vzquez-Vzquez, M.A.
Lpez-Quintela, B.K. Paul, A. Bhaumik,
Microporous Mesoporous Mater. 131 (2010) 373377.[14] Y. Shin,
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(2007)
42974300.[15] Y. Shin, G.J. Exarhos, Mater. Lett. 61 (2007)
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50505052.[17] MASA Samir, F. Alloin, A. Dufresne, Biomacromolecules
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Haul, L. Moscou, R.A. Pierotti, J. Rouquerol,
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Yang, M. Li, N. Jiang, Mater. Res. Bull. 40 (2005) 19681975.[7]
G.B. Biddlecombe, Y.K. Gunko, J.M. Kelly, S.C. Pillai, Coey JMD,
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18781883.[10] F. Jiao, J.C. Jumas, M. Womes, A.V. Chadwick, A.
Harrison, P.G. Bruce, J. Am.prepare a mesoporous -Fe2O3 materials
based on the solgelmethod. The XRD pattern indicated that the
prepared sample washigh purity -Fe2O3. The SEM and TEM results of
the prepared -Fe2O3 sample further veried that the distribution of
size wasreasonably uniform. The nitrogen adsorption analysis showed
thatthe specic surface area and pore volume were 47.26 m2 g1
and0.26 cm3 g1, respectively. Finally, the prepared -Fe2O3
sampleswere used to catalyze the photo degradation of methylene
blue(MB), and the results revealed that the -Fe2O3 prepared with
CNCas template exhibited a much improved photo-catalytic
activitythan that of the sample prepared without CNC during the
course ofMB photo-catalytic degradation process.
Acknowledgements
The authors gratefully acknowledge the nancial support of
theChina Scholarship Council (No. 201307790008, for H. Liang).
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110116.Cellulose nano-crystals (CNC) were used as the template
to
Synthesis of mesoporous -Fe2O3 via solgel methods using
cellulose nano-crystals (CNC) as template and
its...IntroductionExperimentalChemicalsSynthesis of mesoporous
-Fe2O3CharacterizationPhotocatalysis
Results and discussionConclusionsAcknowledgementsReferences