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Sensors and Actuators B 186 (2013) 750– 754

Contents lists available at SciVerse ScienceDirect

Sensors and Actuators B: Chemical

journa l h om epage: www.elsev ier .com/ locate /snb

new alcohols sensor based on cataluminescence on nano-CdS

ue Jiaoa, Lichun Zhanga, Yi Lva, Yingying Sub,∗

Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, ChinaAnalytical & Testing Center, Sichuan University, Chengdu 610064, China

a r t i c l e i n f o

rticle history:eceived 8 May 2013eceived in revised form 5 June 2013ccepted 23 June 2013vailable online 1 July 2013

eywords:ano-CdS

a b s t r a c t

A novel and highly sensitive gas sensor for alcohols (methanol, ethanol, propanol, isopropanol, butanol,and isobutanol) was proposed based on cataluminescence (CTL) on the surface of nano-CdS. Using cetri-monium bromide (CTAB) as template, the nano-sized sensing material CdS was successfully obtained bya simple hydrothermal synthesis process. The luminescence characteristics and the experiment condi-tions were investigated in detail. Under the optimized conditions, little interference was observed whileeleven foreign substances were passing through the sensor. It demonstrated that this gas sensor hashigh selectivity for alcohols. The calibration curve (y = kx + b) of the relative CTL intensity versus the con-

−1

lcoholsataluminescenceas sensor

centration of methanol was made, with the linear range of 1.2–76.1 �g mL and the detection limit of0.5 �g mL−1 (S/N = 3). The relative standard deviation (R.S.D.) (n = 7) of relative cataluminescence inten-sity for 58.5 �g mL−1 methanol was 4.3%. There was no significant change of the catalytic activity of thesensor for a week, with R.S.D. less than 5% by collecting the CTL intensity every hour. The method canbe applied to detect alcohols in the air. The possible mechanism of CTL on the surface of nano-CdS wasdiscussed preliminarily.

. Introduction

Volatile organic compounds (VOCs) including a multitude ofomponents are ubiquitous in the air. Detection of VOCs haseceived much attention in recent years, concerning about envi-onmental protection, human health care, industrial processing anduality control [1,2]. Alcohols, a kind of VOCs, are widely used inedical and clinical applications, food industry, brewing process

ontrol, and bio-technological processes. Therefore, it is necessaryo monitor the concentration of alcohols in the air. Up to now,arious methods have been established for the determination oflcohols, such as semiconductor [3,4] sensors based on the elec-rical conductivity changes and biosensors using enzyme catalyticeaction [5–7]. However, these methods suffer from their respec-ive disadvantages, such as the requirement for many types ofeagents, complicated performance, poor selectivity and stability.s a result, developing a facile, robust and green detection method

or alcohols with greater stability, better selectivity, and lower-costs still of significance.

Since cataluminescence (CTL) was first observed by Breysse

t al. [8] during the catalytic oxidation of carbon monoxide onhe surface of thoria surface, CTL based gas sensors have attractedreat interests with high sensitivity, short response time, simple

∗ Corresponding author. Tel.: +86 28 85412316.E-mail addresses: suyinging@scu.edu.cn, suyinging@163.com (Y. Su).

925-4005/$ – see front matter © 2013 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.snb.2013.06.077

© 2013 Elsevier B.V. All rights reserved.

implementation, low cost, and good suitability for the design ofportable instruments. In 1990s, Nakagawa et al. [9–11] discovereda CTL phenomenon during the catalytic oxidation of organic vaporson �-Al2O3, and established several gas sensors. In recent years,based on different nanomaterials, Zhang and co-workers proposeda series of gas sensors [12–16] and sensor arrays [17,18]. Lu andco-workers also established a sensitive gas sensor based on zeolitefor the detection of n-hexane [19]. Cao et al. reported the vinylacetate sensor and ether sensor, with MgO nanoparticles [20] andthe ZnWO4 [21], respectively. In the previous works of our lab,not only metal oxides, such as CeO2 nanoparticles [22], graphenesheets decorated with SnO2 nanoparticles [23], micro-octahedraMn3O4 [24], nanosized V2O5 [25], Hierarchical hollow microsphereand flower-like In2O3 [26]; but also metal selenides [27] and borateglass [28] were investigated as CTL gas sensor materials. Thus far,the exploit of specific CTL sensing materials with high sensitivityand good selectivity still remains a great challenge.

Semiconductor transition-metal chalcogenides, with theirexcellent luminescent and photochemical properties, have beenextensively studied in many fields [29]. In particular, CdS is oneof the most vital and classical II–VI group semiconductors witha direct band gap of 2.4 eV [30] that have received considerableattention because of their intrinsic properties of a wide band

gap, good chemical stability and ready preparation, and theirtechnological application ranging from microelectronics to non-linear optics, optoelectronics, catalysis, and photoelectrochemicalcell [31–33]. In comparison with the conventional oxide-based

X. Jiao et al. / Sensors and Actuators B 186 (2013) 750– 754 751

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uminescent materials, CdS as sensing materials show advantagesf high catalytic activity and good durability sulfur poisoning.herefore, it is attractive to exploit CdS as a novel CTL sensingaterial.In this work, the nano-CdS was hydrothermally synthesized

sing CTAB as template and strong CTL emission was observedhen alcohols vapor passed through the surface of nano-CdS. Based

n this phenomenon, a new alcohols sensor was designed. Thetudy showed that the as-prepared nano-CdS as sensing materialshowed an excellent specificity toward alcohols by testing the otherleven kinds of common possible VOCs. Moreover, the present sen-or gives a high tolerance to water vapor with great stability. Finally,he possible mechanism of CTL was also discussed.

. Experimental

.1. Reagents

All reagents used in this experiment were of analytical grade.tandard methanol, ethanol, propanol, isopropanol, butanol, andsobutanol were purchased from Kelong Reagent Factory (Chengdu,hina). CdCl2, CTAB and Na2S were purchased from Chengduelong Co. Ltd. (Chengdu, China).

.2. Preparation of materials

The detailed synthesis procedure of nano-CdS was describeds follows: 0.0833 g of CdCl2 and 0.1 g CTAB were dissolved in0 mL distilled water, then 30 ml 0.3 M Na2S solution was addedith continuous stirring for 30 min. Subsequently, the solution was

ransferred into a 100 mL polytetrafluoro-ethylene (PTFE) auto-lave equipped with a stainless steel shell and maintained at80 ◦C for 24 h. After cooling to room temperature, the orange

recipitation was collected through centrifugation and washedeveral times alternately with ethanol and distilled water, and thenacuum-dried at 60 ◦C overnight for the following experiments andharacterizations.

he CTL sensing system.

2.3. Apparatus

The schematic diagram of the CTL detecting system is depictedin Fig. 1. In a typical experiment, 0.1 g of the as-prepared nano-CdS was spread over cylindrical ceramic tubes, and then put itinto a quartz tube with 7 mm inner diameter. The temperature ofthe catalysts could be adjusted by controlling the voltage of theheating tube. A pump with an air cleaner provided a steady airflow stream at a controlled flow rate. A catalytic reaction occurredon the surface of catalysts when the alcohols vapor was carriedby air passing through the quartz tube, CTL emission was imme-diately measured by an Ultra-weak Chemiluminescence Analyzersystem (BPCL). The wavelengths could be selected over the rangeof 400–620 nm by changing the optical filters. Then the resultantgas from sensor was collected in a 3 L sampling bag (Hede Biotech-nology Company, Dalian, China) and introduced into the QP2010GC/MS system (Shimadzu Technologies, Japan) for the analysis ofthe reaction products.

3. Results and discussion

3.1. Characterization of catalysts

The prepared nano-CdS and its precursor were characterizedby power X-ray diffraction (XRD, Tongda TD-3500 Liaoning) witha plumbaginous-monochromatized Cu K� (� = 1.5406 A) radiation.The XRD patterns (Fig. 2) of the precursor with all the peaks cor-responded to the cubic phase of CdS wurtzite structure (JCPDScard no. 65-2887). However, the as-prepared CdS pattern showdiffraction peaks are corresponded to the (1 0 0), (0 0 2) and (1 0 1)crystalline planes of the hexagonal phase of CdS. Although thediffraction line at about 26.51 could also be produced by the (1 1 1)crystalline planes of the CdS cubic phase, the two less intense

diffraction peaks observed at about 25.1 and 28.51 confirm the for-mation of the hexagonal phase. The other weak diffraction peaksthat attributed to (1 1 0), (1 0 3), (2 0 0), (1 1 2) and (2 0 1) planesalso support the existence of the hexagonal phase (JCPDS card no.

752 X. Jiao et al. / Sensors and Actuators B 186 (2013) 750– 754

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isobutanol, butanol) were investigated under the optimal con-ditions. By processing the data of signal intensity in peakheight, a calibration curve for methanol with a linear range of1.2–76.1 �g mL−1 was obtained. The linear regression equation was

ig. 2. XRD patterns of the precursors and prepared nano-CdS (inset: TEM image ofhe prepared nano-CdS).

1-1049). A rough estimate employing Scherrer’s equation [18]ndicates CdS particle size is about 21 nm, which is smaller thanhe precursor particles.

The transmission electron microscopy (TEM) image was takenn a Tecnai G2F20 S-TWIN (FEI) transmission electron microscope,nd was shown in inset of Fig. 2. The sample consists of poly-edral shape 20 ± 8 nm in diameter. The as-prepared CdS waslso investigated through FT-IR spectra (Fig. S1). Weak and broadeaks at 3000–3750 cm−1 were observed in the spectrum of CdS,hich is mainly due to the physically adsorbed water on the

amples. The absorption peak at 1700 cm−1 of the as-prepareddS was due to the vibration of carbonyl group. The TG profilexhibits slight weight loss stages in the temperature over 800 ◦CFig. S2), which is testified the good stability of this sensing mate-ial. In addition, N2 adsorption–desorption isotherms were alsomployed to investigate the specific surface area and the pore struc-ures of prepared sample. The BET surface area estimated fromarret–Joyner–Halenda (BJH) analysis of the isotherms was deter-ined to be 29.6 m2 g−1. The average of the pore size distribution is

.430 nm, which was calculated from the absorption branch by theJH method. Usually, the higher surface area of materials causeshe higher catalytic activity for oxidation [34]. Strong CTL emissionould be observed when alcohols vapor passed through the surfacef nano-CdS, which was selected for quantitative detection in theubsequence work.

.2. Optimization

.2.1. Optimization of emission wavelengthThe CTL properties on the as-prepared nano-CdS were investi-

ated by a continuous sampling of methanol vapor (46.8 �g mL−1)ith an air flow rate at 300 mL min−1. The optimal emission wave-

ength was investigated with a series of interference filter in theegion of 460–640 nm (460, 490, 535, 555, 575, 620 and 640 nm),ig. 3 shows the maximal emission of methanol was at 575 nm withhe maximum signal to noise (S/N) ratio. Therefore, the 575 nm washosen as the optimal detection wavelength in the subsequenceork.

.2.2. Optimization of working temperatureThe effect of working temperature on cataluminescence was

till a very important factor. To investigate the effect of tempera-ure on the CTL intensity, 46.8 �g mL−1 methanol was determinedt various temperatures. The signal intensity and S/N versus theatalysis temperature at 300 mL min−1 air flow rate under the

Fig. 3. CTL spectra emission on CdS and S/N ratio. Working temperature: 330 ◦C andair flow rate: 300 mL min−1. Error bars stand for ±S.D.

wavelength of 575 nm is presented in Fig. 4. The CTL intensity formethanol increased with the increasing temperature, but a signifi-cant decrease of S/N appeared at about 330 ◦C due to the increasingnoise. So, 330 ◦C was chosen for further exploration.

3.2.3. Optimization of air flow rateAir flow rate also plays an important role in the catalumines-

cence of methanol on nano-CdS, and the influence of the flowrate of the air on the CTL intensity was studied in the range of100–400 mL min−1 at 330 ◦C with a band-pass filter of 575 nm.From the results in Fig. 5, it can be seen that from 100 to400 mL min−1, CTL intensity and S/N increase with the increase ofcarrier flow rate reached a maximum at 250 mL min−1. However,at higher flow rates (>250 mL min−1), the CTL intensity and S/Nbecame low, probably because the reaction time between methanoland CdS was not sufficient. Therefore, the flow rate of 250 mL min−1

was chosen as the optimum air flow rate in the following experi-ment.

3.3. Analytical characteristics

Further study for the analytical characteristics of the CTL per-formance to alcohols (methanol, ethanol, isopropanol, propanol,

Fig. 4. Effect of working temperature on the CTL intensity and S/N. Air flow rate,300 mL min−1 and wavelength, 575 nm. Error bars stand for ±S.D.

X. Jiao et al. / Sensors and Actuators B 186 (2013) 750– 754 753

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[35,36], possible mechanism of the CTL of propanol is as the fol-lowing:

CH3CH2CH2OH + CdS + O2 → CH3CH2CHO∗

ig. 5. Effect of air flow rate on the CTL intensity and S/N. Temperature, 330 ◦C andavelength, 575 nm. Error bars stand for ±S.D.

= 53.53 + 31.24X (correlation coefficient R = 0.9978), where Y washe CTL intensity and X was the concentration of methanol ing mL−1. The limit of detection (LOD) defined as 3 N/S (N refers

o the noise and S refers to the slope of the calibration curve)as 0.5 �g mL−1. As shown in Fig. S3, the relative standard devi-

tion (R.S.D. n = 7) was 4.3% for 58.5 �g mL−1 methanol. The linearegression equations and LOD of alcohols are shown in Table 1.

.4. Specificity of nano-CdS gas sensor

During the study, it can be found that the as-prepared nano-CdSs sensing materials showed an excellent specificity toward alco-ols by testing the other eleven kinds of common possible VOCs,

ncluding acetone, butanone, tetrachloromethane, formaldehyde,cetaldehyde, propanal, benzene, toluene, formic acid, acetic acid,nd propionic acid under the same investigating conditions withhe concentration of about 60 �g mL−1 at 330 ◦C and the flow ratef 250 mL min−1. It can be seen from Fig. 6, methanol, ethanol, iso-ropanol, propanol, isobutanol, and butanol have significantly highmission intensity, formic acid and tetrachloromethane have weakmission, and other compounds have no or very weak emission.he results demonstrated that the prepared CdS is a good candidateensing material for the selective determination of alcohols.

.5. Stability of CdS sensor

The stability and durability of the CdS sensor was examinedy continually introducing 29.3 �g mL−1 methanol into the sensornder the optimal experiment conditions. After a week, no signifi-ant changes of the catalytic activity could be observed, with R.S.D.ess than 5% by collecting the CTL intensity every hour. Therefore,

he present sensor showed a good long-term stability. The sensorlso gives a high tolerance to water vapor. As shown in Fig. S4 inhe supporting information, it is obvious that the catalytic activityf sensing material is less affected by water vapor.

able 1he linear regression equations and LODs of alcohols (ethanol, isopropanol,ropanol, isobutanol, butanol).

Sample Linear regressionequation

R Linear range(�g mL−1)

LOD(�g mL−1)

Ethanol Y = 14.88x − 44.95 0.9996 11.7–434 7.1Isopropanol Y = 7.81x + 80.31 0.9977 17.5–233 2.0Propanol Y = 6.71x + 103.90 0.9941 11.9–150 2.4Isobutanol Y = 6.94x + 105.09 0.9971 18.0–150 2.6Butanol Y = 10.11x + 34.88 0.9956 18.0–72.0 5.5

Fig. 6. Selectivity of the alcohols sensor. Conditions: wavelength, 575 nm; temper-ature, 330 ◦C and air flow rate, 250 mL min−1.

3.6. Possible mechanism

As a widely accepted theory about CL reaction, the luminescenceemission is obtained when the excited intermediates produced fallto ground state [13]. In our experiment, a strong CTL emissioncould be observed when methanol, ethanol, isopropanol, propanol,isobutanol, and butanol vapor was delivered through the surfaceof nano-CdS by air, respectively. However, no CTL emission couldbe observed when t-butanol vapor passed through the surface ofnano-CdS. In study of the oxidation of ethanol, Zhang et al. [35,36]proposed a mechanism of intermediate involving the oxidationprocesses of the two intermediates originated from the ethanoloxidation. For the sake of studying CTL mechanism of the alcoholssensor, GC–MS experiments were carried out to detect the inter-mediates of the catalytic oxidation of alcohols. All the results ofGC–MS demonstrated that aldehyde or ketone was produced, whenthe alcohols vapor passed through the surface of nano-CdS exceptt-butanol. GC–MS spectrograms of the propanol and t-butanol cata-luminescence products are shown in Fig. 7. It can be seen thatthere are two main peaks corresponding to propanol and propanal,which can be identified by comparison of their retention time ofthe standard gases. But no other component peak is obtained exceptt-butanol when t-butanol vapor passes through the surface of nano-CdS. According to these phenomena and the literatures reported

Fig. 7. GC–MS of the propanol (black) and t-butanol (red) cataluminescence prod-ucts. (For interpretation of the references to color in this figure legend, the reader isreferred to the web version of this article.)

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54 X. Jiao et al. / Sensors and A

. Conclusion

In summary, a sensitive alcohols sensor was developed basedn the CTL on nano-CdS hydrothermally synthesized. The influ-nces of wavelength, temperature, and carrier gas flow rate onhe CTL intensity were investigated. Under the optimized condi-ions, a wide linear range with a detection limit of 0.5 �g mL−1 for

ethanol was obtained. In addition, the present gas sensor alsoas high selectivity and good stability for other alcohols includingethanol, ethanol, isopropanol, propanol, isobutanol, and butanol.ue to the high sensitivity, good selectivity and stability, a poten-

ial application of this work is the development of a portable sensoror alcohols in food and environment.

cknowledgement

The authors gratefully acknowledge financial support from theational Natural Science Foundation of China (No. 21105067 and1075084).

ppendix A. Supplementary data

Supplementary data associated with this article can be found, inhe online version, at http://dx.doi.org/10.1016/j.snb.2013.06.077.

eferences

[1] B.E. Lippy, R.W. Turner, Complex mixtures in industrial workspaces: lessons forindoor air quality evaluations, Environmental Health Perspectives 95 (1991)81–83.

[2] M.J. Mendell, Indoor residential chemical emissions as risk factors for-respiratory and allergic effects in children: a review, Indoor Air 17 (2007)259–277.

[3] L.J. Bie, X.N. Yan, J. Yin, Y.Q. Duan, Z.H. Yuan, Nanopillar ZnO gas sensor forhydrogen and ethanol, Sensors and Actuators B: Chemical 126 (2007) 604–608.

[4] K. Aguir, A. Labidi, E. Gillet, R. Delamare, M. Maaref, Ethanol and ozone sensingcharacteristics of WO3 based sensors activated by Au and Pd, Sensors andActuators B: Chemical 120 (2006) 338–345.

[5] C.R. Raj, S. Behera, Mediatorless voltammetric oxidation of NADH and sensingof ethanol, Biosensors and Bioelectronics 21 (2005) 949–956.

[6] L.N. Wu, M. McIntosh, X.J. Zhang, H.X. Ju, Amperometric sensor for ethanolbased on one-step electropolymerization of thionine–carbon nanofibernanocomposite containing alcohol oxidase, Talanta 74 (2007) 387–392.

[7] K. Mitsubayashi, H. Matsunaga, G. Nishio, S. Toda, Y. Nakanishi, Bioelectronicsniffers for ethanol and acetaldehyde in breath air after drinking, Biosensorsand Bioelectronics 20 (2005) 1573–1579.

[8] M. Breysse, L. Faure, M. Guenin, R.J.J. Williams, T. Wolkenstein, Chemi-luminescence during the catalysis of carbon monoxide oxidation on a thoriasurface, Journal of Catalysis 45 (1976) 137–144.

[9] K. Utsunomiya, M. Nakagawa, N. Sanari, M. Kohata, T. Tomiyama, I. Yamamoto,T. Wada, N. Yamashita, Y. Yamashita, Continuous determination and discrim-ination of mixed odour vapours by a new chemiluminescence-based sensorsystem, Sensors and Actuators B: Chemical 25 (1995) 790–793.

10] M. Nakagawa, S. Kawabata, K. Nishiyama, K. Utsonomiya, I. Yamamoto, T. Wada,Y. Yamashita, N. Yamashita, Analytical detection system of mixed odor vaporsusing chemiluminescence-based gas sensor, Sensors and Actuators B: Chemical34 (1996) 334–338.

11] M. Nakagawa, T. Okabayashi, T. Fujimoto, K. Utsunomiya, I. Yamamoto, T. Wada,Y. Yamashita, N. Yamashita, A new method for recognizing organic vapor byspectroscopic image on cataluminescence-based gas sensor, Sensors and Actu-ators B: Chemical 51 (1998) 159–162.

12] Z.Y. Zhang, K. Xu, Z. Xing, X.R. Zhang, A nanosized Y2O3-based catalytic chemi-luminescent sensor for trimethylamine, Talanta 65 (2005) 913–917.

13] J.J. Shi, R.X. Yan, Y.F. Zhu, X.R. Zhang, Determination of NH3 gas by combinationof nanosized LaCoO3 converter with chemiluminescence detector, Talanta 61(2003) 157–164.

14] K.W. Zhou, X.L. Ji, N. Zhang, X.R. Zhang, On-line monitoring of formaldehyde inair by cataluminescence-based gas sensor, Sensors and Actuators B: Chemical119 (2006) 392–397.

15] Y.F. Zhu, J.J. Shi, Z.Y. Zhang, C. Zhang, X.R. Zhang, Development of a gas sensor

utilizing chemiluminescence on nanosized titanium dioxide, Analytical Chem-istry 74 (2001) 120–124.

16] M.R. Almasian, N. Na, F. Wen, S.C. Zhang, X.R. Zhang, Development of a plasma-assisted cataluminescence system for benzene, toluene, ethylbenzene, andxylenes analysis, Analytical Chemistry 82 (2010) 3457–3459.

rs B 186 (2013) 750– 754

17] N. Na, S.C. Zhang, X. Wang, X.R. Zhang, Cataluminescence-based array imagingfor high-throughput screening of heterogeneous catalysts, Analytical Chem-istry 81 (2009) 2092–2097.

18] Y.Y. Wu, N. Na, S.C. Zhang, X. Wang, D. Liu, X.R. Zhang, Discrimination and iden-tification of flavors with catalytic nanomaterial-based optical chemosensorarray, Analytical Chemistry 81 (2009) 961–966.

19] P. Yang, X.N. Ye, C.W. Lau, Z.X. Li, X. Liu, J.Z. Lu, Design of efficient zeolite sensormaterials for n-hexane, Analytical Chemistry 79 (2007) 1425–1432.

20] C.C. Wu, X.A. Cao, Q. Wen, Z.H. Wang, Q.Q. Gao, H.C. Zhu, A vinyl acetatesensor based on cataluminescence on MgO nanoparticles, Talanta 79 (2009)1223–1227.

21] X.A. Cao, W.F. Wu, N. Chen, Y. Peng, Y.H. Liu, An ether sensor utilizing catalumi-nescence on nanosized ZnWO4, Sensors and Actuators B: Chemical 137 (2009)83–87.

22] Y.L. Xuan, J. Hu, K.L. Xu, X.D. Hou, Y. Lv, Development of sensitive carbon disul-fide sensor by using its cataluminescence on nanosized-CeO(2), Sensors andActuators B: Chemical 136 (2009) 218–223.

23] H.J. Song, L.C. Zhang, C.L. He, Y. Qu, Y.F. Tian, Y. Lv, Graphene sheets deco-rated with SnO2 nanoparticles: in situ synthesis and highly efficient materialsfor cataluminescence gas sensors, Journal of Materials Chemistry 21 (2011)5972–5977.

24] L.C. Zhang, Q. Zhou, Z.H. Liu, X.D. Hou, Y.B. Li, Y. Lv, Novel Mn3O4 microocta-hedra: promising cataluminescence sensing material for acetone, Chemistry ofMaterials 21 (2009) 5066–5071.

25] H.L. Zhang, L.C. Zhang, J. Hu, P.Y. Cai, Y. Lv, A cataluminescence gas sensorbased on nanosized V2O5 for tert-butyl mercaptan, Talanta 82 (2010) 733–738.

26] P.Y. Cai, W. Bai, L.C. Zhang, H.J. Song, Y.Y. Su, Y. Lv, Hierarchical hollow micro-sphere and flower-like indium oxide: controllable synthesis and application asH2S cataluminescence sensing materials, Materials Research Bulletin 47 (2012)2212–2218.

27] S.X. Xu, L.C. Zhang, X.F. Zhang, C.L. He, Y. Lv, Synthesis of Ag2Se nanomaterialby electrodeposition and its application as cataluminescence gas sensor mate-rial for carbon tetrachloride, Sensors and Actuators B: Chemical 155 (2011)311–316.

28] J. Hu, K.L. Xu, Y.Z. Jia, Y. Lv, Y.B. Li, X.D. Hou, Oxidation of ethyl ether on borateglass: chemiluminescence, mechanism, and development of a sensitive gassensor, Analytical Chemistry 80 (2008) 7964–7969.

29] J.G. Yu, J. Zhang, S.W. Liu, Ion-exchange synthesis and enhanced visible-lightphotoactivity of CuS/ZnS nanocomposite hollow spheres, Journal of PhysicalChemistry C 114 (2010) 13642–13649.

30] Y. Kanemitsu, T. Nagai, Y. Yamada, T. Taguchi, Temperature dependence of free-exciton luminescence in cubic CdS films, Applied Physics Letters 82 (2003)388–390.

31] A.P. OdrinskiÏ., A critical analysis of investigation of deep levels in high-resistivity CdS single crystals by photoelectric transient spectroscopy,Semiconductors 38 (2004) 298–303.

32] F. El-Tantawy, K.M. Abdel-Kader, F. Kaneko, Y.K. Sung, Physical properties ofCdS-poly (vinyl alcohol) nanoconducting composite synthesized by organosoltechniques and novel application potential, European Polymer Journal 40(2004) 415–430.

33] R. Faez, I.M. Martin, M. De Paoli, M.C. Rezende, Influence of processing timeand composition in the microwave absorption of EPDM/PANI blends, Journalof Applied Polymer Science 83 (2002) 1568–1575.

34] Z.Y. Sun, H.Q. Yuan, Z.M. Liu, B.X. Han, X.R. Zhang, A highly efficient chemi-cal sensor material for H2S: alpha-Fe2O3 nanotubes fabricated using carbonnanotube templates, Advanced Materials 17 (2005) 2993–2997.

35] X.O. Cao, Z.Y. Zhang, X.R. Zhang, A novel gaseous acetaldehyde sensor utilizingcataluminescence on nanosized BaCO3, Sensors and Actuators B: Chemical 99(2004) 30–35.

36] Q. Ye, Q. Gao, X.R. Zhang, B.Q. Xu, Cataluminescence and catalytic reactionsof ethanol oxidation over nanosized Ce1−xZrxO2 (0 ≤ x ≤ 1) catalysts, CatalysisCommunications 7 (2006) 589–592.

Biographies

Xue Jiao received her B.S. degree in 2010 from Sichuan University, Chengdu, China.Now she is perusing her M.S. from Sichuan University, China. Her current researchinterests include nanomaterials and gas sensors.

Lichun Zhang received her Ph.D. from Sichuan University in 2010. Now she worksat College of Chemistry, Sichuan University, China. Her areas of interest are thesynthesis of nanomaterials and their application in chemical sensor and biosensor.

Yi Lv received his Ph.D. from Southwest China Normal University (the currentSouthwest University) in 2003. He is currently a professor of chemistry at SichuanUniversity, China. His research interests are mainly in the areas of luminescence

based sensors and nanomaterials for analytical chemistry.

Yingying Su received her Ph.D. from Sichuan University in 2007. Now she worksat Analytical & Testing Center, Sichuan University, China. Her areas of interest areseparation technique, chemiluminescence and luminescence-based sensor.