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Electrochimica Acta 56 (2011) 7377– 7384

Contents lists available at ScienceDirect

Electrochimica Acta

jou rn al hom epa ge: www.elsev ier .com/ locate /e lec tac ta

novel material based on cupric(II) oxide/macroporous carbon and itsnhanced electrochemical property

ing Bai, Xiangjie Bo, Charles Luhana, Liping Guo ∗

aculty of Chemistry, Northeast Normal University, Changchun 130024, PR China

r t i c l e i n f o

rticle history:eceived 22 March 2011eceived in revised form 6 May 2011ccepted 23 May 2011vailable online 24 June 2011

a b s t r a c t

A novel material based on cupric(II) oxide/macroporous carbon nanocomposites (CuO/MPC) has beenprepared through a simple hydrothermal process. In the process of synthesis, the incorporation of MPCleads to a well-dispersed CuO nanoneedles on the surface of MPC. The new composite material combinedthe unique property of CuO and MPC, showed improved electrochemical activity towards H2O2 reductionand glucose oxidation. Based on the improved electrochemical property of CuO/MPC modified electrode,

eywords:upric oxideacroporous carbonydrogen peroxidelucose

it can be used as sensor for the determination of H2O2 and glucose. In addition, the CuO/MPC modifiedelectrode displayed good stability and antifouling features towards glucose oxidation. These results alsoindicate that CuO/MPC nanocomposites have of wide application foreground.

© 2011 Elsevier Ltd. All rights reserved.

lectrochemical property

. Introduction

Cupric oxide (CuO), an important p-type semiconducting mate-ial (energy gap of 1.4 eV) [1], has attracted enormous attention inecent years from both fundamental and practical reasons. It can beidely used in applications such as gas sensor, magnetic storageedia, electronics, solar-energy transformation, semiconductors

nd catalysis [2–6]. Recently, CuO is proposed as a promisinglectrode material for electrochemical sensors, due to its inexpen-ive, non-toxic, easily produced, readily stored and high specificapacitances. For example, Miao et al. have proposed a chemicallyodified electrode with nano-CuO targeting at the detection of2O2 with high sensitivity and high stability [7]. Moreover, glucose

ensors have also been fabricated using CuO nanowires synthesizedn a Cu rod [8]. Because different morphologies of CuO nanos-ructures can greatly influence its electrochemical properties [9],t is reasonable to expect that processing CuO into nanostructured

aterials could enhance its performance in the electrochemicalctivity. Various nanostructured CuO with different sizes haveeen synthesized. Conventional methods for the preparation ofuO nanostructures include one step solid state reaction at roomemperature, thermal decomposition of copper salts, mechanical

illing of commercial powders, and so on [10–12]. However, nonef these methods seems to be suitable for the preparation of highlyispersed CuO nanostructures, which has been found to be an

∗ Corresponding author. Tel.: +86 0431 85099762; fax: +86 0431 85099762.E-mail address: guolp078@nenu.edu.cn (L. Guo).

013-4686/$ – see front matter © 2011 Elsevier Ltd. All rights reserved.oi:10.1016/j.electacta.2011.05.095

obstacle to many applications, especially in catalysts and electrodes[13,14].

Recently, several new synthetic approaches have been devel-oped with the aim of obtaining well-dispersed CuO nanostructures.For instance, dandelion-like CuO hollow microspheres have beensuccessfully fabricated through a simple hydrothermal methodwith the cationic surfactant CTAB as the template [15]. Kumaret al. developed a new sonochemical method to prepare CuOnanoparticles in organic solvents and obtained well-dispersed CuOnanoneedles [16]. However, due to the poor conductivity of CTABand organic molecules, both the conduction between the CuOnanoneedles and the electrodes and that between the neighbor-ing CuO nanoneedles are obstructed; therefore, the conductivity ofthe CuO may be lowered. This is unfavorable for use as electrodematerial.

Porous materials have recently captured much attention in thefields of adsorption, electrochemical double capacitors, and evensemiconductor and space technologies, because of the hydropho-bic nature of their surface, high surface area, large pore volumes aswell as chemical inertness, and good thermal and mechanical sta-bility [17–19]. Numerous studies dealing with the preparation andcharacterization of these materials are reported in literature [20].Recently, porous materials were used widely as catalyst supportfor well-dispersed nanomaterials [21–29]. Therefore, introducingporous materials into the reaction systems for preparing well-

dispersed CuO nanostructures provides a possible way to obtaincomposites with excellent electrochemical performance.

In this report, we incorporated macroporous carbon (MPC)into the process of CuO nanostructures synthesis and obtained

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ell-dispersed CuO nanoneedles. Also H2O2 and glucose weresed as probes to characteristic the electrochemical properties ofuO/MPC nanocomposites. The as-prepared CuO/MPC nanocom-osites show high sensitivity, stability, and fast amperometricesponse towards H2O2 reduction as well as improved electro-hemical activity for glucose oxidation compared with the CuOrepared without MPC. Moreover, the presence of a high concen-ration of chloride ions does not affect the determination of glucose.

. Experimental

.1. Reagents and apparatus

Hydrogen peroxide (H2O2) and d-glucose was obtained fromeijing Chemical Company (Beijing, China). The freshly prepared-glucose solution was allowed to come to mutarotation equilib-ium by standing overnight. All other chemicals not mentioned hereere of analytical reagent grade and were used as received. All

olutions were freshly prepared with deionized water. The 0.1 Modium hydroxide (NaOH) was employed as a supporting elec-rolyte.

The phases of the samples were identified by powder X-rayiffraction (XRD) analysis using an X-ray D/max-2200vpc (Rigakuorporation, Japan) instrument operated at 40 kV and 20 mA andsing Cu K� radiation (� = 0.15406 nm). The morphology of theroducts was determined by transmission electron microscopyTEM) using a Hitachi H-600 operated at 75 keV. The scanning elec-ron microscopy (SEM) images were determined with a PhilipsL-30 ESEM operating at 3.0 kV. Electrochemical experimentsere performed with a CHI830b Electrochemical Workstation (CH

nstruments, Shanghai Chenhua Instrument Corporation, China) in conventional three-electrode cell. The working electrode usedas glassy carbon electrode (GCE, 3 mm diameter). A platinum

lectrode was applied as the counter electrode and an Ag/AgCl (inaturated KCl solution) electrode served as reference electrode. Allolutions were purged with high-purity nitrogen for at least 15 mino remove oxygen prior to the beginning of the experiments. In thisaper, all experiments were carried out at room temperature.

.2. Preparation of MPC

MPC was synthesized according to the previous reports [30,31].riefly, about 2.0 g SiO2 template was added to a solution contain-

ng 2.5 g of sucrose, 0.15 mL of 98% H2SO4 and 10 mL of distilledater. The mixture was heated at 10 ◦C for 6 h, followed by heating

t 150 ◦C for a further 6 h. Complete carbonization was accom-lished by heating the composite in a tube oven in vacuo at 850 ◦Cor 2 h. The residual surface carbon was removed from the com-osite and the SiO2 template was then etched away by overnightissolution in 10% aqueous HF to leave behind a macroporous car-on.

.3. Preparation of CuO/MPC nanocomposites

A typical synthesis of pure CuO was carried out as follows32]: 25 mL of Cu(NO3)2·3H2O (1.0 M, in pure ethanol) was addedith 25 mL of ammonia solution (25%) and 5 mL of aqueous NaOH

1.0 M). One set of the solution mixture was transferred to a Teflon-ined stainless steel autoclave which was then heated at 120 ◦C for4 h. After reaction, the autoclave was cooled naturally and theroducts were washed with deionized water and absolute ethanol

everal times. The final products were dried in vacuum at 60 ◦C for2 h. The CuO/MPC nanocomposites were prepared in the same wayy ultrasonificating 50 mg MPC in Cu(NO3)2·3H2O solution beforedding ammonia and NaOH.

Fig. 1. The XRD patterns of pure CuO (a), MPC (b) and CuO/MPC nanocomposites(c).

2.4. Electrode preparation

Prior to the modification, the GCE was polished with 1.0, 0.3and 0.05 �m alumina slurry, respectively, and sonicated succes-sively in 1:1 nitric acid, absolute alcohol and double-distilledwater. The cleaned electrode was dried with high-purity nitrogensteam. CuO/MPC nanocomposites modified GCE (CuO/MPC/GCE)was prepared by casting 5 �L of CuO/MPC suspension (10 mL N,N′-dimethylformamide (DMF) and 10 mg CuO/MPC) on GCE surface,and dried under an infrared lamp. For comparison, CuO modifiedGCE (CuO/GCE) were prepared in the same way.

3. Results and discussion

3.1. Structural characterization

Fig. 1 shows the XRD patterns of the CuO samples (a), MPC (b)and CuO/MPC nanocomposites (c). All of the peaks in curve a can beidentical to the single-phase CuO with a monoclinic structure andthe diffraction data are in good agreement with JCPDS card of CuO(JCPDS 41-0254). The obvious peak observed at 2� = 22.4◦ in curveb was attributed to graphite carbon C (0 0 2) (JCPDS 75-1261). TheXRD pattern shown in curve c is the product obtained by synthesisof CuO in the presence of MPC. The diffraction peaks can be clearlyindexed to both phases with them on CuO and them on MPC. Thisconfirms that CuO has been successfully grafted on the surface ofMPC.

SEM is used to character the structure of samples (Fig. 2). Itis clear that the pore size of MPC, corresponded exactly to theSiO2 spheres size, is about ∼100 nm (Fig. 2A). Fig. 2B indicates thatthe morphology of the pure CuO is needle-like with the widthin hundreds of nanometers. But the nanoneedles form aggrega-tive nanostructures and poor distribution. The best morphologywith smaller nanoneedles and good distribution are obtained forsample CuO/MPC in Fig. 2C. The role of MPC on the morphologyof CuO is obvious. Fig. 2D is the typical nitrogen (77 K) adsorp-tion/desorption isotherm of the prepared MPC, which belongs tothe type IV isotherm according to the IUPAC classification. It con-tains a sharp capillary condensation step at very high relativepressures (p/p0 > 0.9) and an H1-type hysteresis loop, indicating theexistence of large pores in the material [33], which is in accordance

with the SEM of MPC.

The morphologies of as-prepared products are also shown inFig. 3. As the TEM images shown, the uniform large pores of MPCare clearly visible in Fig. 3A and the pore size is about 110 nm. As

J. Bai et al. / Electrochimica Acta 56 (2011) 7377– 7384 7379

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Fig. 2. SEM images of (A) MPC, (B) pure CuO, (C) CuO/MPC nanoc

hown in Fig. 3B, the CuO nanostructures appear long needle-likeorphology with 100-300 nm in width and thousands of nanome-

ers in length. They are poorly dispersed and typically aggregatedo large regiments. The aggregation may reduce the active surfacerea of nanostructures. But the incorporation of MPC changes theorphology of CuO (Fig. 3C). They become shorter and narrower.

Fig. 3. TEM images of (A) MPC, (B) pure CuO, (C) CuO/MPC nanocompos

sites and (D) nitrogen adsorption–desorption isotherms for MPC.

The CuO nanostructures are uniformly dispersed on MPC supportswithout aggregation. Fig. 3D is a more clear enlarged drawing of

CuO/MPC nanocomposites. We can clearly see the long needle-likeCuO nanostructures with average 50 nm in width and 300 nm inlength. This is because CuO can be confined in the channels of MPCand its particles are prevented from aggregation.

ites and (D) the high magnification of CuO/MPC nanocomposites.

7380 J. Bai et al. / Electrochimica Acta 56 (2011) 7377– 7384

Fig. 4. (A) Nyquist plots at GCE (a), CuO/GCE (b), MPC/GCE (c) and CuO/MPC/GCE (d) in 5 mM K3Fe(CN)6/0.1 M KCl solution. (B) CVs of CuO/GCE (a) and CuO/MPC/GCE (b) in0.1 M NaOH solution at 50 mV s−1.

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ig. 5. CVs recorded at (A) MPC/GCE, (B) CuO/GCE and (C) CuO/MPC/GCE in the a0 mV s−1.

.2. Electrochemical characterization

To study the electrochemical properties of the prepared prod-

cts, the electrochemical impedance spectroscopy (EIS) is used tonalyze the different electrodes. This can give useful informationf the impedance changes on the electrode surface. Fig. 4A shows

ig. 6. (A) Amperometric responses of the MPC/GCE (a), CuO/GCE (b) and CuO/MPC/GCalibration curves at the MPC/GCE (d), CuO/GCE (e) and CuO/MPC/GCE (f).

e (dot lines) and presence (solid lines) of 1.0 mM H2O2 in 0.1 M NaOH. Scan rate:

the results of EIS for the bare GCE (curve a), CuO/GCE (curve b),MPC/GCE (curve c) and CuO/MPC/GCE (curve d) in the presence of5.0 mM K3[Fe(CN)6]/0.1 M KCl. The EIS includes a semicircular part

and a linear part. The semicircular part at higher frequencies corre-sponds to the electron transfer limited process, and the diameter isequivalent to the electron transfer resistance (Rct). The linear part

E (c) with successive addition of 0.1 mM H2O2 into 0.1 M NaOH. (B) The related

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t lower frequencies corresponds to the diffusion process. Fromig. 4A, curve a, it can be seen that bare GCE exhibits a semicircleart at high frequency. Rct can be estimated to be 248 � at GCE.fter being modified with CuO nanoneedles on GCE, the semicircleiameter of EIS increases and Rct increases to 1380 �, indicatinghe appearance of the CuO nanomaterials on GCE surface [34–36].or MPC/GCE the diameter of semicircle markedly decrease andct decreases to 17 �, indicating the much lower electron trans-er resistance on MPC/GCE compared with that on CuO/GCE andCE. Whereas, for the CuO/MPC/GCE Rct is 43 � between MPC/GCEnd CuO/GCE. In other words, the electron transfer ability of CuOas been greatly improved by incorporating MPC. These resultsemonstrate that MPC can form good electron pathway betweenhe electrode and electrolyte and be expected as a good platformor sensing applications.

Fig. 4B shows the cyclic voltammograms (CVs) of CuO/GCEcurve a) and CuO/MPC/GCE (curve b) in 0.1 M NaOH solution. Itan be seen that there are three anodic peaks and two cathodiceaks in the potential range of −1.0 to +0.3 V on both modifiedlectrodes, which can be attributed to a series of redox processetween Cu(0) and copper oxide. This is similar with the pre-ious report [37]. We also find that the redox peak currents athe CuO/MPC/GCE are much larger than that at the CuO/GCE. It

ay have been because different size of CuO nanoneedles has dif-erent electrochemical active and because the presence of MPCue to superior conductivity promotes the charge transfer ofuO.

.3. Electrochemical property of CuO/MPC nanocomposites

To better understand the electrochemical property of CuO/MPCanocomposites, H2O2 and glucose are introduced in the elec-rolyte as probes in this study.

.3.1. H2O2The electrochemical activity of the CuO/MPC nanocomposites

owards the H2O2 reduction is studied by CV. Also, its electro-eduction behaviors of H2O2 on MPC/GCE (A), CuO/GCE (B) anduO/MPC/GCE (C) are investigated and compared in this work.s is shown in Fig. 5A, no reduction peak can be observed with-ut the addition of H2O2 at the MPC/GCE (dot line). However,hen 1.0 mM H2O2 is present, a current response can be observed

t around −0.2 V (vs. Ag/AgCl) (solid line), which is possibly dueo MPC [38]. For CuO/GCE and CuO/MPC/GCE, a couple of smallxidative and reductive peaks are observed for both electrodesn the absence of H2O2, which are assignable to the oxidationnd reduction of Cu species and agreement with that in Fig. 4B.pon addition of 1.0 mM H2O2, for CuO/GCE, the reduction cur-

ent has a sensed increased at around −0.36 V (Fig. 5B, solid line).he reduction peak potential of H2O2 is more negative at theuO/GCE than that at MPC/GCE, but the peak current of H2O2 athe CuO/GCE is higher than that at the MPC/GCE. The increasef current indicates the significant electrochemical activity ofuO to H2O2. For CuO/MPC/GCE, however, when 1.0 mM H2O2 isdded, a substantial negative shift of the cathodic peak poten-ial (−0.2 V) and dramatic increase of current signal are observeds depicted in Fig. 5C (solid line). Compared with MPC/GCE anduO/GCE, the CuO/MPC/GCE shows the highest electrochemicalctivity for the reduction of H2O2. The electrochemical activityf CuO/MPC nanocomposite is significantly better than pure MPCr CuO, which may be due to the synergic effect of MPC anduO.

The amperometric responses of the CuO/GCE (curve a), MPC/GCEcurve b) and CuO/MPC/GCE (curve c) at a constant potential of0.20 V to successive additions of 0.1 mM H2O2 in 0.1 M NaOH are

ompared in Fig. 6A. It could be seen that the response signals are

Fig. 7. Current–time responses at −0.2 V with an increasing glucose concentrationper 60 s for the CuO/MPC/GCE. The inset is calibration curves.

increasing with the increase of the concentration of H2O2. Con-sistent with the results of CV (Fig. 5), the CuO/MPC/GCE yields amuch larger current response than CuO/GCE and MPC/GCE. Also, itis observed that the response time of the electrodes to achieve thesteady-state current is <3 s, 5 s and 5 s for CuO/MPC/GCE, CuO/GCEand MPC/GCE, respectively. Plots of the steady-state current versusH2O2 concentration yielded the calibration curves are shown inFig. 6B (curves d–f). The corresponding sensitivities at CuO/GCE,MPC/GCE and CuO/MPC/GCE are 0.153 �A/mM, 1.49 �A/mM and2.94 �A/mM, respectively. Obviously, CuO/MPC/GCE exhibits fasterresponse time and higher sensitivity compared with CuO/GCEand MPC/GCE. The results indicate that the CuO/MPC/GCE showthe highest electrochemical activity. It can be attributed tothe increase of electroactive surface area and the synergisticelectrochemical activity by combining CuO nanoneedles withMPC.

To verify its workability, the sensor based on the CuO/MPC/GCEis applied to the determination of H2O2 in different concentration.Fig. 7 illustrates current–time plots for CuO/MPC/GCE with succes-sive step changes of H2O2 concentration. The CuO/MPC/GCE givesa linear dependence in the H2O2 concentration range of 1.0 × 10−5

to 6.5 × 10−3 M with a detection limit of 0.2 �M at a signal/noiseratio of 3, as depicted in inset of Fig. 7. It was concluded thatCuO/MPC/GCE can be used as sensor for the determination of H2O2.

3.3.2. GlucoseTo further compare the electrochemical property of different

electrodes, glucose is introduced in the electrolyte as electroac-tive probes in this study. Fig. 8 shows the CVs of the MPC/GCE(A), CuO/GCE (B) and CuO/MPC/GCE (C) in 0.1 M NaOH without(dot line) and with 2 mM glucose (solid line). With the additionof glucose to the solution, only a negligible response, starting atabout +0.45 V, is sensed with the MPC/GCE (A). For CuO/GCE (B)and CuO/MPC/GCE (C), upon addition of glucose, the oxidationof glucose start at +0.3 V and meanwhile the oxidation currenthas a marked increase. Moreover, the peak current density ofCuO/MPC/GCE is about 7 times of that obtained from CuO/GCE.The increase of the glucose oxidation current could be ascribedto well-dispersed CuO nanoneedles which may be having highresponse activities. The results suggest CuO/MPC/GCE exhibits abetter electrochemical response for glucose oxidation compared

with MPC/GCE and CuO/GCE, which may result from the synergis-tic effect between high conductivity MPC and well-dispersed CuOnanoneedles.

7382 J. Bai et al. / Electrochimica Acta 56 (2011) 7377– 7384

Fig. 8. CVs recorded at (A) MPC/GCE, (B) CuO/GCE and (C) CuO/MPC/GCE in the absence (dot lines) and presence (solid lines) of 2.0 mM glucose in 0.1 M NaOH. Scan rate:50 mV s−1.

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ear relationship in the range of 3.5 × 10−6 M to 3.0 × 10−4 M(inset B of Fig. 10). The linear regression equation is expressed asip (A) = 3.5 × 10−8 + 0.00143c(M) (R = 0.9973). The detection limit

ig. 9. (A) Amperometric responses of the MPC/GCE (a), CuO/GCE (b) and CuO/MPalibration curves at the MPC/GCE (d), CuO/GCE (e) and CuO/MPC/GCE (f).

For further clarification of these results, the amperomet-ic responses of MPC/GCE (curve a), CuO/GCE (curve b) anduO/MPC/GCE (curve c) at a constant potential of +0.30 V to suc-essive additions of glucose in 0.1 M NaOH are compared in Fig. 9A.s shown, CuO/MPC/GCE responds very rapidly (3 ± 1 s) and favor-bly to these changes in the glucose concentration, however,o obvious response is observed in analogous measurements atuO/GCE and MPC/GCE. Obviously, as a low-potential ampero-etric sensor for glucose detection, CuO/MPC/GCE exhibits faster

esponse time and higher sensitivity compared with CuO/GCEnd MPC/GCE. The corresponding calibration curves of all threelectrodes are presented in Fig. 9B. The linear response pro-ides the sensitivity. The sensitivities at MPC/GCE, CuO/GCE anduO/MPC/GCE are 0.07 �A/mM, 0.18 �A/mM and 1.43 �A/mM. Itan be seen that the CuO/MPC/GCE shows excellent oxidationf glucose in basic solution and high sensitivity to glucose con-entration change. This is owing to the nanocomposite naturef our CuO/MPC electrode based on MPC, which facilitates highlectrochemical activity towards glucose and large active surfacerea.

The sensor based on the CuO/MPC/GCE is also applied tohe determination of glucose in different concentration. Fig. 10

llustrates current–time plots for CuO/MPC/GCE with succes-ive step changes of glucose concentration from 5.0 × 10−7 to.0 × 10−2 M. Inset A of Fig. 10 shows a magnified diagram ofhe low concentration determination of glucose. The dependence

E (c) with successive addition of 0.1 mM glucose into 0.1 M NaOH. (B) The related

of response currents on the concentration of glucose is a lin-

Fig. 10. Current–time responses at +0.3 V with an increasing glucose concentra-tion from 5.0 × 10−7 to 2.0 × 10−2 M per 60 s for the CuO/MPC/GCE. Inset: (A) themagnified diagram of the low concentration determination of glucose and (B) thecalibration curves for glucose at CuO/MPC/GCE.

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ig. 11. Amperometric response of the CuO/MPC/GCE to 0.5 mM glucose withoutcurve a) and with 0.2 M NaCl (curve b) in a 0.1 M NaOH solution. The inset is theelated calibration curves without (curve c) and with 0.2 M NaCl (curve d).

S/N = 3) is 2 �M at a signal/noise ratio of 3. It is concluded thatuO/MPC/GCE can be used as sensor for the determination of glu-ose.

In the case of glucose detection, the possible interferences athe CuO/MPC/GCE have also been investigated (data not shown).t is concluded that 0.1 mM dopamine (DA) and 0.1 mM uriccid (UA) have no influence on the 2.0 mM glucose detection atuO/MPC/GCE. However, 0.1 mM ascorbic acid (AA) slightly inter-ered with the measurement of glucose. The interferences webtained for AA is less than 7.0%, which is far lower than 27.0%e et al. obtained using unmodified MWCNTs array electrode39].

As reported, many glucose sensors based on precious metal andlloy, their activities can be easily lost due to the poisoning of chlo-ide ions [8,40,39,41]. Herein, in order to evaluate the antifoulingbility of the CuO/MPC/GCE, the amperometric response of theuO/MPC/GCE to 0.5 mM glucose (Fig. 11) is examined withoutcurve a) and with 0.2 M NaCl (curve b) in a 0.1 M NaOH solution. Ashown in Fig. 11, the current response of the CuO/MPC/GCE remainsnchanged towards glucose oxidation in the presence of 0.2 M NaCl

n a 0.1 M NaOH solution. The linear response for glucose at theuO/MPC/GCE remains almost constant (inset of Fig. 11, curves cnd d), implying that the electrode can be used as a glucose sensorn the presence of chloride.

The enhancement of the electrochemical activity of CuO/MPCanocomposites may arise from the following three aspects.irst, the well-dispersed CuO nanoneedles on the surface of MPCenders more accessible surfaces of CuO nanoneedles for the2O2 reduction and glucose oxidation reaction, leading to theirigher electrochemical activity. Second, due to high conductiv-

ty of the MPC, the fast charge transfer through the compositesay result in their high electrochemical activity. Third, the small

ize of CuO nanoneedles in the composites may also contributeo the improvement of the electrochemical performance of theomposites.

.4. Reproducibility and stability of the CuO/MPC/GCE

Based on the well electrochemical property, the CuO/MPCanocomposites can be used as a new class of electrode material forlectrochemical applications. So the tests of reproducibility and sta-

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bility are very important. The reproducibility of the CuO/MPC/GCEwas evaluated via the comparison of the currents of differentelectrodes for the determination of glucose. The amperometricresponse of three CuO/MPC/GCE to 0.1 mM glucose was tested inde-pendently, and the relative standard deviation (RSD) was 4.43%. Inaddition, the current responses of the CuO/MPC/GCE to 0.1 mM glu-cose recorded over about 8 min (data not shown), with only 15%current diminutions, reflecting the good stability of the nonen-zymatic glucose sensor. The good stability of CuO/MPC/GCE canbe attributed to the chemical stability of CuO in basic solution[2].

4. Conclusion

In this paper, a new composite material made from depositedCuO nanoneedles onto MPC by a simple method has been pre-pared successfully. The CuO/MPC/GCE displays substantially higherelectrochemical activity to H2O2 reduction and glucose oxida-tion with a higher current response than the CuO/GCE andMPC/GCE. So the CuO/MPC/GCE is successfully used as sensorfor the determination of H2O2 and glucose. Moreover, the pres-ence of a high concentration of chloride ions does not affect thedetermination of glucose. These results demonstrate that the intro-duction of MPC can enhance the electrochemical properties of CuOand this nanocomposite will offer a wide perspective for manyapplications.

Acknowledgement

The authors gratefully acknowledge the financial support by theNational Natural Science Foundation of China (No. 21075014).

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