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: lianghunan202@163.com (H. Liang),liuk1103@163.com (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, R.J. Macfarlane, M.R. Langille, C.A. Mirkin, Chem. Rev.111 (2011) 37363827.[12] A. Lezau, M. Trudeau, G.M. Tsoi, L.E. Wenger, D. Antonelli, J. Phys. Chem. B 108

(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, J.M. Blackwood, I.T. Bae, B.W. Arey, G.J. Exarhos, Mater. Lett. 61 (2007)

42974300.[15] Y. Shin, G.J. Exarhos, Mater. Lett. 61 (2007) 25942597.[16] Y. Zhou, E.Y. Ding, W.D. Li, Mater. Lett. 61 (2007) 50505052.[17] MASA Samir, F. Alloin, A. Dufresne, Biomacromolecules 6 (2005) 612626.[18] T. Sugimoto, H. Itoh, T. Mochida, J. Colloid Interf. Sci. 205 (1998) 4245.[19] K.S.W. Sing, D.H. Everett, R.A.W. Haul, L. Moscou, R.A. Pierotti, J. Rouquerol,

et al., Pure Appl. Chem., 57, (1985) 603619.[20] J. Qiu, R. 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, M.J. Venkatesan,Mater. Chem. 11 (2001) 29372939.

[8] R. Fan, X.H. Chen, Z. Gui, L. Liu, Z.Y. Chen, Mater. Res. Bull. 36 (2001) 497502.[9] D.N. Srivastava, N. Perkas, A. Gedanken, I. Felner, J. Phys. Chem. B 106 (2002)

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).

References

[1] N.D. Feng, Q. Wang, A.M. Zheng, Z.F. Zhang, J. Fan, S.B. Liu, et al., J. Am. Chem.Soc. 135 (2013) 16071616.

[2] W.T. Sun, Q.Q. Meng, L. Jing, D.N. Liu, Y.J. Cao, Phys. Chem. C 117 (2013)13581365.

[3] Z.H. Wei, R.G. Xing, X. Zhang, S. Liu, H.H. Yu, P.C. Li, Appl. Mater. Interf. 5 (2013)598604.

[4] H. Zhang, G. Zhao, T.K. Zhang, F.J. Teng, Alloy Compd. 603 (2014) 3541.[5] Y. Zhang, J. Gu, M. Murugananthan, Y.R.J. Zhang, Alloy Compd. 630 (2015)

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