High quality Pt–graphene nanocomposites for efficient electrocatalytic nitrite sensing

Colloids and Surfaces A: Physicochem. Eng. Aspects 481 (2015) 43–50

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Colloids and Surfaces A: Physicochemical and Engineering Aspects journal homepage: www.elsevier.com/locate/colsurfa

High quality Pt–graphene nanocomposites for efficient electrocatalytic nitrite sensing Beibei Yang a , Duan Bin a , Huiwen Wang a , Mingshan Zhu b , Ping Yang a , Yukou Du a,∗ a b

College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, PR China Department of Chemistry, University of Toronto, Canada

h i g h l i g h t s

g r a p h i c a l

a b s t r a c t

• Pt nanoparticles-reduced graphene oxide composites are fabricated by one-pot hydrothermal method. • The composite has an enhanced electrochemical activity toward the oxidation of nitrite. • Amperometric response presents an especially high sensitivity of 496.4 ␮A mM−1 . • The prepared electrode is used as a sensor for the determination of nitrite in beverage samples.

a r t i c l e

i n f o

Article history: Received 20 January 2015 Received in revised form 2 April 2015 Accepted 6 April 2015 Available online 25 April 2015 Keywords: Electrochemical sensor Nitrite Graphene Pt nanoparticles Hydrothermal synthesis

a b s t r a c t A promising electrochemical sensor, Pt nanoparticles decorated on the surface of reduced graphene oxide (RGO) sheets were facilely synthesized by a one-pot hydrothermal method. The morphology and composition of as-prepared Pt–RGO composites have been characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and X-ray diffraction (XRD). It is found that Pt nanoparticles with ca. 4.81 ± 1.54 nm in diameter were evenly distributed on the surface of RGO sheets. The cyclic voltammetry shows that Pt–RGO nanocomposite has a higher electron transfer rate and remarkable increase electrochemical activity toward the oxidation of nitrite. The amperometry reveals that the Pt–RGO modified electrode exists a good linear relationship between peak current and concentration of nitrite with a low detection limit of 0.1 ␮M and high sensitivity of 496.4 ␮A mM−1 . Moreover, the as-synthesized Pt–RGO electrode display a fast amperometric response within 4 s. Compared to the bare Pt nanoparticles or the RGO modified glassy carbon (GC) electrode, the as-synthesized Pt–RGO nanocomposite shows a well reproducibility, stability and anti-interference electrocatalytic performance toward nitrite sensing. © 2015 Elsevier B.V. All rights reserved.

1. Introduction ∗ Corresponding author. Tel.: +86 512 65880089; fax: +86 512 65880089. E-mail address: [email protected] (Y. Du). http://dx.doi.org/10.1016/j.colsurfa.2015.04.027 0927-7757/© 2015 Elsevier B.V. All rights reserved.

Many scientists have been extensively intrigued by nitrite which is widely used in our daily life as food additive, fertilizing agents

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B. Yang et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 481 (2015) 43–50

and corrosion inhibitor, while its excess level can interact with amines to form carcinogenic N-nitrosamines [1–5]. The World Health Organization (WHO) has reported that nitrite can damage the spleen, kidneys and nervous system, and has a forceful correlation with high cancer levels when its concentration is higher than 4.5 mg mL−1 [6]. As a consequence, rapid, accurate and economic determination of nitrite has attracted much attention. Many techniques have been developed for nitrite determination including spectrofluorimetry [7], spectrophotometry [8], ion chromatography [9], chemiluminescence [10,11], high-performance liquid chromatography [12], etc. It must be pointed out that most of above methods are reliable but time-consuming, complicated, and expensive [12,13]. Owing to the rapid response, cheap, safe, simple instrumentation and easy operation, electrochemical techniques have been currently employed for the detection of nitrite [14–16]. However, it has long been known that the use of bare electrodes such as carbon electrodes, gold and platinum tend to be poisoned by the species formed during the electrochemical process [17]. Noble metal nanoparticles, due to the high specific surface area, high surface-to-volume ratio, extremely small size and unique physicochemical characteristics, were acted as promising electrocatalyst for electrochemical sensing [18–20]. Among these noble metal nanoparticles, metallic Pt nanoclusters have been attracted extensive attention owing to their extraordinary electrocatalytic activities [18–24]. For example, Miao et al. [23] used functionalization of Pt nanoparticles (Pt NPs) for electrochemical detection of nitrite, a detection limit as high as 5 ␮M with a sensitivity of 26.7 ␮A mM−1 was obtained. Wang et al. [24] used Pt nanoclusters for electrochemical detection of nitrite and they obtained a low detection limit of 0.4 ␮M with a high sensitivity of 88.5 ␮A mM−1 . More recently, graphene, a two-dimensional carbon material has attracted tremendous attention because of its extraordinary electronic and electrocatalytic properties [25–27]. Up to now, several graphene-based nanocomposites as precursors were applied to determine nitrite [28–32]. For example, Mani et al. [30] used chemically reduced graphene oxide for the determination of nitrite and a narrow linear range of 8.9–167 ␮M with a sensitivity of 26.7 ␮A mM−1 was obtained. Jiao et al. [32] used Au nanoparticles decorated reduced graphene oxide (Au/RGO) for the determination of nitrite and obtained a more broad linear range of 0.05–8.5 ␮M with a high sensitivity of 473.5 ␮A mM−1 . However, Pt nanoclusters modified graphene nanocomposites for electrochemical detection of nitrite have been hitherto rarely reported. Consequently, considering the general and broad interest in graphene based nanostructures, promising electrocatalytic for electrochemical sensing of Pt nanoclusters and the importance of environmental problems as well, an investigation on the development of graphene hybridized Pt electrosensor for the electrocatalytic detection of nitrite might provide more and new opportunities for sensitive nitrite detection, which is an issue of paramount importance. Herein, Pt nanoparticles decorated on the surface of reduced graphene oxide (RGO) sheets were facilely synthesized by a one-pot hydrothermal method. The ethylene glycol was used as the reductive agent for both graphene oxide and H2 PtCl6 under synthetic conditions. It is found that Pt nanoparticles with ca. 4.81 ± 1.54 nm in diameter were evenly distributed on the surface of RGO sheets. Moreover, the cyclic voltammetry shows that Pt–RGO nanocomposite has a high electron transfer rate and remarkable increase electrochemical activity toward the oxidation of nitrite. Compared to the bare Pt nanoparticles and the RGO modified glassy carbon electrode (GCE), the as-synthesized Pt–RGO nanocomposite shows a well reproducibility, stability and anti-interference electrocatalytic performance toward nitrite sensing. Moreover, the as-prepared Pt–RGO electrode was used to determine nitrite in commercial beverage samples and exhibited an efficient detective activity. The present work might open up new possibilities for the

development of highly sensitive and anti-interference electrosensor for nitrite detection. 2. Experimental 2.1. Materials and reagents Graphite powder, sodium nitrite (NaNO2 ), potassium ferrocyanide (K4 Fe(CN)6 ), potassium ferricyanide (K3 Fe(CN)6 ), disodium hydrogen phosphate (Na2 HPO4 ) and sodium dihydrogen phosphate (NaH2 PO4 ) were purchased from Sinopharm Chemicals Reagent Co., Ltd. Chloroplatinic acid hexahydrate (H2 PtCl6 ·6H2 O) and ethylene glycol (EG) were purchased from Shanghai Shiyi Chemicals Regent Co., Ltd. Beverage was purchased from the supermarket. All other chemicals were of analytical-grade purity and used without further purification. Double distilled water was used throughout all the experiments, the phosphate buffered saline solutions (PBS, Na2 HPO4 /NaH2 PO4 , 0.1 M) of different pH were used as the electrolyte in the electrochemical reduction process. 2.2. Apparatus The morphology and composition of the as-formed electrode were studied by transmission electron microscopy (TEM) performed with a TecnaiG220 (FEI America) operating at 200 kV and energy-dispersive X-ray analyzer (EDX) (S-4700, Hitachi High Technologies Corporation, Japan). X-ray photoelectron spectroscopy (XPS) was performed on an ESCALab220i-XL electron spectrometer from VG Scientific using 300 W Al K␣ radiation. Raman spectra were recorded on a Renishaw Invia Plus Raman microscope using a 633 nm argon ion laser. The X-ray diffraction (XRD) measurement is performed on a PANalytical X’ Pert PRO MRD ˚ operated at 40 kV and system with Cu-K␣ radiation ( = 1.54056 A) 30 mA. Electrochemical measurements were carried out on a CHI 650D electrochemical workstation (Shanghai Chenhua Instrument Plant, China) with a standard three-electrode. The glassy carbon electrode (GCE) with a diameter of 3 mm and its modified electrode were used as working electrodes, a Pt wire as the counter electrode and saturated calomel electrode (SCE) as the reference electrode. All of the measurements were carried out at room temperature. 2.3. Synthesis of Pt–RGO composites Firstly, graphene oxide (GO) nanosheet was synthesized by previous reported method [33,34]. Then, 20 mg GO and 2.7 mL H2 PtCl6 aqueous solution (7.5 mM) were added into the mixture solution containing 10 mL double distilled water and 40 mL ethylene glycol. After ultrasonicated for 120 min, the pH value of this ink was adjusted to 12.5 with NaOH solution (1.0 M). Subsequently, the mixed solution was transferred into a Teflon-lined autoclave. The autoclave was maintained at 140 ◦ C for 4 h, and then cooled down to the room temperature. The black precipitate was centrifuged and washed three times with double-distilled water. After that, the precipitate was dispersed in 20 mL double-distilled water, after 60 min of sonication, the homogenous suspension of 0.2 mg mL−1 Pt + 1 mg mL−1 RGO was obtained. For comparison, 1 mg mL−1 RGO or 0.2 mg mL−1 Pt were synthesized with the similar conditions in the absence of GO or H2 PtCl6 aqueous solution, respectively. 2.4. Preparation of modified electrode For the electrochemical experiments, the electrode was fabricated by a modification of GCE using our Pt–RGO, RGO, or Pt nanoparticles. Before modification, the GCE was firstly polished with alumina powder (0.05 ␮m) to obtain a mirror-like surface, and

B. Yang et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 481 (2015) 43–50

then rinsed with ethanol and water in an ultrasonic bath. Subsequently, 10 ␮L above-synthesized suspensions (Pt–RGO, RGO, or Pt nanoparticles) were dropped on the cleaned GCEs and dried in air for 20 min, resulting in Pt–RGO/GCE, RGO/GCE and Pt/GCE, respectively. 3. Results and discussion 3.1. Characterizations of Pt–RGO electrode Experimentally, Pt nanoparticles decorated on the surface of RGO sheets were facilely synthesized by a one-pot hydrothermal method. The EG was used as the reductive agent for both GO and H2 PtCl6 under synthetic conditions. As shown in Fig. 1A, a typical wrinkled texture of RGO sheet is appeared in our as-prepared sample. It also can be seen that the as-synthesized Pt nanoparticles are well-distributed on the surface of RGO sheet without obvious agglomerations. From the inset of Fig. 1A and the histogram of the size of the Pt nanoparticles on the surface of RGO sheet in Fig. 1B, the Pt nanoparticles have a very narrow size distribution with an average diameter of 4.81 ± 1.54 nm. This excellent dispersion and

45

small size of Pt nanoparticles might give rise to a high active surface area for Pt–RGO electrode, and thus may exhibit their excellent electrocatalytic performance toward nitrite oxidation. The composition of the Pt–RGO nanocomposites were analyzed by EDX experiment, as shown in Fig. 2. It can be seen that after hydrothermal reaction, Pt, C, O element were detected, which can confirm the formation of RGO hybridized Pt nanostructures. To demonstrate the successful reduction of GO during hydrothermal process, the significant structural changes occurring during the chemical processing from GO to RGO are analyzed by XPS spectra. As shown in Fig. 3, the C1s XPS spectrum of GO is divided into four peaks located at 284.8 eV (C C C bonds), 286.8 eV (C O bonds), 287.8 eV (C O bonds), 289.0 eV (O C O bonds), respectively [35,36]. Among these, the C C C bonds and C O bonds are dominated, indicating the considerable degree of oxidation in GO. The C1s XPS spectrum of Pt–RGO presents the same components, however, the intensity of the peak attributed to C C C bonds appears dominantly and the peaks corresponding to the oxygen functionalized C (C O and O C O) are much weaker than those in GO, suggesting that the remarkable deoxygenation occurred during the chemical reduction.

Fig. 1. (A) TEM image of Pt–RGO nanocomposite. (B) The histogram of the size of the Pt nanoclusters on the surface of RGO sheet. The inset in plan (A) is a high resolution TEM image of Pt–RGO nanocomposites.

Fig. 2. EDX spectrum of the Pt–RGO nanoparticle and the quantitative elemental analysis result.

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B. Yang et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 481 (2015) 43–50

Fig. 5. XRD pattern of Pt–RGO nanocomposites.

Fig. 3. XPS spectra of pure GO sheets and Pt–RGO nanocomposites.

Fig. 4. Raman spectra of GO nanosheets and Pt–RGO nanocomposites.

Raman spectroscopy is a powerful tool to determine the surface nanostructure of graphene-based materials. Accordingly, Raman spectra were further measured for confirming the reduction of GO during the hydrothermal process. As shown in Fig. 4, the two prominent peaks of D band (due to the doubly degenerate E2g mode at the Brillouin zone center) and G band (arises from the defect mediated zone-edge phonons, near K-point) [37,38] are observed in both samples. However, the Pt–RGO nanocomposite exhibits an increased D/G intensity ratio (1.16) compared to GO (0.95), indicating a decrease in average size of sp2 domain upon the reduction of GO [38]. On the other hand, the D and G bands exhibit a shift toward lower frequencies from GO to Pt–RGO nanocomposite (D: from 1350 cm−1 to 1319 cm−1 , G: from 1598 cm−1 to 1587 cm−1 ). This is an indication that the Pt–RGO nanocomposite displays an interaction between Pt and RGO sheets, demonstrating that the RGO sheets are hybridized with Pt successfully. The crystal structure of the nanocomposites can be measured by X-ray diffraction (XRD). Fig. 5 shows the XRD patterns of Pt–RGO nanocomposites. The two peaks at around 39.95◦ and 46.24◦ are respectively attributed to the diffraction peaks of crystal faces Pt (1 1 1) and (2 0 0), respectively [39]. It is worthwhile noting that the typical diffraction peak of C at 24.17◦ is attributed to C (0 0 2) due to the reduction of GO to RGO [40]. Accordingly, based on the above results, it can be solidly confirmed that the metallic Pt and RGO are generated in our nanocomposites.

3.2. Electrochemical behaviors of Pt–RGO electrode The cyclic voltammetry (CV) responses of Pt–RGO/GCE, Pt/GCE and RGO/GCE in a 2.5 mM [Fe(CN)6 ]3−/4− + 0.1 M KCl solution are investigated in Fig. 6A. The quasi-reversible one-electron redox behavior of ferricyanide ions is observed at the three modified electrodes. Compared with the CV response of Pt/GCE and RGO/GCE, a high current and narrow peak potential difference are obtained in the CV response of Pt–RGO/GCE, indicating that the introduction of Pt nanoparticles on RGO surface can enhance the electrochemical activity of the as-prepared electrode. This could be attributed to the special structure of RGO [41,42] and the increased active surface area of the well distributed Pt nanoparticles. The CV responses of the three electrodes in 0.1 M PBS (pH 7.0) with 1 mM NaNO2 are recorded to understand the electrocatalytic behaviors toward the oxidation of NaNO2 . As Fig. 6B depicted, at Pt/GCE and RGO/GCE, the oxidation of nitrite exhibits two inconspicuous peaks. While at Pt–RGO/GCE, a prominent peak and high current appear at 0.75 V demonstrate that the heterogeneous electron transfer rate of the Pt–RGO electrode is fast, and thus greatly facilitate the oxidation of nitrite. Compared to other electrochemical methods on the oxidation of nitrite, such as the RGO modified GCE at 0.8 V [30], Pt nanoclusters modified GCE at 0.82 V [24], CuO nanoparticles modified GCE at 0.84 V [43], the Pt–RGO electrode shows lower oxidation potential, it may be attributed to the high density of sp2 [44]. 3.3. Electrochemical determination of nitrite Fig. 7A shows the CVs of Pt–RGO/GCE in 0.1 M PBS containing 1 mM NaNO2 at different pH values from 3.0 to 9.0. It can be observed that the maximum oxidation current of nitrite appears at pH 7.0. When the pH is lower than 7.0, the instability of nitrite anions in acidic conditions due to its decomposition reaction of − the conversion of NO− 2 to NO and NO3 may cause the decrease peak current [45]. Additionally, it is observed that with the increase of pH value, the oxidation peak potentials shift to more negative potentials. A linear relationship is found between Epa and pH, and the equation is expressed as follows: Epa (V) = 0.8164–0.0595 pH (R2 = 0.998) (as Fig. 7B shown). The slope value of −59.5 mV/pH which is close to the Nernst system, defined as −59 mV/pH at 25 ◦ C, implying that the total number of electrons and protons taking part in the charge transfer are the same [46]. As we know, investigating the effect of scan rate on the oxidation peak potential and peak current can evaluate the kinetics of electrode reaction. Fig. 8A shows the CVs of Pt–RGO/GCE in 0.1 M PBS (pH 7.0) containing 1 mM NaNO2 at different scan

B. Yang et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 481 (2015) 43–50

47

Fig. 6. (A) CVs in 2.5 mM Fe(CN)6 3−/4− + 0.1 M KCl solution at RGO/GCE, Pt/GCE, Pt–RGO/GCE electrodes. Scan rate: 50 mV s−1 . (B) CVs in 0.1 M PBS (pH 7.0) containing 1 mM NaNO2 at RGO/GCE, Pt/GCE, Pt–RGO/GCE electrodes. Scan rate: 50 mV s−1 .

Fig. 7. (A) The pH influence of the solutions in 0.1 M PBS containing 1 mM NaNO2 with pH 3.0–9.0 at Pt–RGO/GCE electrode. Scan rate: 50 mV s−1 . (B) Variation of peak potential vs. pH.

Fig. 8. (A) CVs at Pt–RGO/GCE in 0.1 M PBS (pH 7.0) containing 1 mM NaNO2 with varying scan rates from 20 mV s−1 to 200 mV s−1 . Inset: plots of the anodic peak current vs. scan rate. (B) Plots of the anodic peak potential vs. the logarithm of scan rate.

rates from 20 mV s−1 to 200 mV s−1 . A good linearity is obtained while plotting the current against the scan rate: Ipa (␮A) = 2.6317 (mV s−1 ) + 121.53 with R2 = 0.996 (inset of Fig. 8A), indicating that the oxidation of nitrite is dominated by the surface adsorptioncontrolled process. Further, as Fig. 8B shown a linear relationship is presented between Epa and lg , and the regression equation is: Epa (V) = 0.09738 lg  (mV s−1 ) + 0.761 (R2 = 0.998). According to Laviron equation: [47]

0

Epa = E + 2.30

 RT   RTk0  anf

lg

anf

+ 2.30

 RT  anf

lg u

(1)

The number of transfer electron (n) in electro-oxidation of nitrite is calculated about 2, which is in agreement with the Eq. (2) [48]. NO2 − + H2 O → NO3 − + 2H+ + 2e−

(2)

3.4. Amperometric determination of nitrite Fig. 9A depicts the typical amperometric response of Pt–RGO/GCE with successive addition of nitrite into the 20 mL 0.1 M PBS (pH 7.0) solution at an applied potential of 0.75 V. The response time of nitrite is observed within 4 s, suggesting the fast diffusion of nitrite on the electrode surface. The obtained oxidation

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Fig. 9. (A) Amperometric i–t curve at Pt–RGO/GCE for the determination of NaNO2 in 0.1 M PBS (pH 7.0). Each addition increases the concentration of 10 ␮L 0.5 mM NaNO2 , 100 ␮L 1 mM NaNO2 , 200 ␮L 1 mM NaNO2 ; EPP = 0.75 V. (B) Plots of concentration of NaNO2 vs. paek current. Table 1 Comparison of different modified electrodes for nitrite determination. Electrode CR-GO/GCE K-doped graphene/GCE Graphene/polycyclodextrin/ MWCNTs/GCE AuNPs/SG/GCE FeT4 MPyP/CoTSPc/ GCE PEDOT nanorods/GCE Pt nanoclusters/GCE CuO nanoparticles/GCE AuNPs/CLDH/GCE Pt–RGO/GCE

Linear range (␮M) 8.9–167 0.5–3.9

LOD (␮M) 1 0.2

Sensitivity (␮A mM−1 )

Reference

26.7 90

[30] [49]

0.8

[50]

5–6750

1.65

10–3960 0.2–8.6

0.2 0.04

45.44 370

[51] [52]

4–40

0.57

22.8

[53]

0.4

88.5

[24]

0.3

12.69

[43]

1.2–900 4–3700 1–191 0.25–90

0.5 0.1

382.2 496.4

[54] This work

MWCNTs: multiwall carbon nanotubes; FeT4 MPyP: iron(III) tetra-(N-methyl-4pyridyl)-porphyrin; CoTSPc: cobalt(II) tetrasulfonated phthalocyanine; PEDOT: unique poly(3,4-ethylenedioxythiophene; AuNPs: gold nanoparticles; SG: sulfonated graphene; CLDH: copper calcined layered double hydroxide.

currents are linear with the concentration of nitrite in the range of 0.25 − 90 ␮M (as Fig. 9B shown): Ipa (␮A) = 0.4946 C (␮M) + 1.525 with R2 = 0.997. The detection limit is estimated to be 0.1 ␮M, based on S/N = 3 and the Pt–RGO/GCE that shows an extremely high sensitivity of 496.4 ␮A mM−1 , which is higher than those modified electrodes listed in Table 1. Moreover, the detection limit and sensitivity are better than those of other Pt nanostructures [23,24]. 3.5. Interference, reproducibility and stability The determination of nitrite in the presence of 1000-fold common interfering ions such as Cu2+ , SO4 2− , K+ , Cl− , NH4 + , F− , Ni2+ , NO3 − , Na+ , HCO3 − is investigated by amperometry. Fig. 10 displays that these interferences have no significant interference with the deviations below 5%, indicating that these ions do not obviously affect the determination of NO2 − . The reproducibility is evaluated using CV responses in 0.1 M PBS (pH 7.0) solution containing 1 mM NaNO2 with ten electrodes produced under the same condition. The relative standard deviation (R.S.D.) for nitrite biosensors is 2.8% which indicates the Pt–RGO composite is highly reproducible. When the electrodes are stored for 15 days at room temperature, the decrease oxidation peak about 4.8% is obtained. Therefore, the Pt–RGO/GCE with a well anti-interference, reproducibility and stability can be used as a stable sensor.

Fig. 10. Amperometric response at Pt–RGO/GCE for 5 ␮M of NaNO2 in the presence of 1000-fold: CuSO4 , Ni(NO3 )2 , KCl, NaHCO3 , NH4 F. Table 2 Determination of nitrite at various concentrations in beverage. Added (␮M)

Found (␮M)

Recovery (%)

R.S.D. (%) (n = 5)

30 40 50

30.68 43.06 49.2

102.3 107.6 98.4

3.8 2.6 4.9

3.6. Beverage sample analysis The highly sensitive electrocatalytic detection of nitrite on Pt–RGO electrodes means that the nanocomposites might be used as an efficient sensor in practical application. Accordingly, the practical application of as-synthesized Pt–RGO modified GC electrode is tested by adding the standard samples into the supernatant to determine the concentrations of nitrite in commercial beverage samples. The beverage was purchased and diluted 100 times with 0.1 M PBS (pH 7.0) before experiments and the spiked nitrite concentrations were 30, 40 and 50 ␮M, respectively. As shown in Table 2, the recoveries are 102.3%, 107.6% and 98.4%, correspondingly. The good recovery is obtained suggesting the practical applicability of the proposed method. 4. Conclusions In summary, Pt nanoparticles were decorated on the surface of RGO sheets via a facile one-pot hydrothermal method, where the EG was used as the reductive agent for both GO and H2 PtCl6 under synthetic conditions. The Pt nanoparticles with small size were well dispersed on the surface of RGO sheets. The CVs show that the as-synthesized Pt–RGO nanocomposite has a high electron transfer rate and remarkable increase electrochemical activity

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toward the oxidation of nitrite. Moreover, the Pt–RGO nanocomposite shows a well reproducibility, stability and anti-interference electrocatalytic performance toward nitrite sensing compared to the bare Pt nanoparticles or the RGO modified GC electrode. Furthermore, the Pt–RGO is applied to the determination of nitrite in commercial beverage samples with satisfactory results. The present work indicated that the Pt–RGO nanocomposites might be used as an extremely promising candidate applicable for a wide range of electrochemical sensing and biosensing applications. Acknowledgments This work was supported by the National Natural Science Foundation of China (Grant No. 51373111), Suzhou Nano-Project (ZXG2012022), the Opening Project of Xinjiang Key Laboratory of Electronic Information Materials and Devices (XJYS0901-2010-01), the Academic Award for Young Graduate Scholar of Soochow University, the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and the Project of Scientific and Technologic Infrastructure of Suzhou (SZS201207). References [1] K. Anoop, T. Viraraghavan, Nitrate removal from drinking water – review, J. Environ. Eng. 123 (1997) 371–380. [2] B.F. Jay, B.S. Francis, The determination of nitrite: a critical review, Anal. Chem. 15 (2008) 283–313. [3] J.M. Matthew, D. James, G.C. Richard, Detection and determination of nitrate and nitrite: a review, Talanta 54 (2001) 785–803. [4] L.Y. Jiang, R.X. Wang, X.M. Li, L.P. Jiang, G.H. Lu, Electrochemical oxidation behavior of nitrite on a chitosan–carboxylated multiwall carbon nanotube modified electrode, Electrochem. Commun. 7 (2005) 597–601. [5] R. Ojani, J.B. Raoof, E. Zarei, Electrocatalytic reduction of nitrite using ferricyanide application for its simple and selective determination, Electrochim. Acta 52 (2006) 753–759. [6] S.A. Kyrtopoulos, N-nitroso compound formation in human gastric juice, Cancer Surv. 8 (1989) 423–428. [7] G.D. Tarigh, F. Shemirani, Development of a selective and pH-independent method for the analysis of ultra trace amounts of nitrite in environmental water samples after dispersive magnetic solid phase extraction by spectrofluorimetry, Talanta 128 (2014) 354–359. [8] C.E. Pasquali, L.P.F.A. Hernando, J.S.D. Alegrıa, Spectrophotometric simultaneous determination of nitrite, nitrate and ammonium in soils by flow injection analysis, Anal. Chim. Acta 600 (2007) 177–182. [9] N.N. Wang, R.Q. Wang, Y. Zhu, A novel ion chromatography cycling-columnswitching system for the determination of low-level chlorate and nitrite in high salt matrices, J. Hazard. Mater. 235/236 (2012) 123–127. [10] A.F. Lagalante, P.W. Greenbacker, Flow injection analysis of imidacloprid in natural waters and agricultural matrixes by photochemical dissociation, chemical reduction, and nitric oxide chemiluminescence detection, Anal. Chim. Acta 590 (2007) 151–158. [11] H. Kodamatani, S. Yamazaki, K. Saito, T. Tomiyasu, Y. Komatsu, Selective determination method for measurement of nitrite and nitrate in water samples using high-performance liquid chromatography with post-column photochemical reaction and chemiluminescence detection, J. Chromatogr. A 1216 (2009) 3163–3167. [12] I. Ferreira, S. Silva, Quantification of residual nitrite and nitrate in ham by reverse-phase high performance liquid chromatography/diode array detector, Talanta 74 (2008) 1598–1602. [13] C. Welch, R. Compton, The use of nanoparticles in electroanalysis: a review, Anal. Bioanal. Chem. 384 (2006) 601–619. [14] C.A. Ramdance-Terbouche, A. Terbounche, S. Djebbar, D. Hauchard, Electrochemical sensors using modified electrodes based on copper complexes formed with algerian humic acid modified with ethylenediamine or triethylenetetramine for determination of nitrite in water, Talanta 119 (2014) 214–225. [15] V. Mani, B. Dinesh, S.M. Chen, R. Saraswathi, Direct electrochemistry of myoglobin at reduced graphene oxide–multiwalled carbon nanotubes–platinum nanoparticles nanocomposite and biosensing towards hydrogen peroxide and nitrite, Biosens. Bioelectron. 53 (2014) 420–427. [16] B.Q. Yuan, C.Y. Xu, L. Liu, Y.F. Shi, S.T. Li, R.C. Zhang, Polyethylenimine-bridged graphene oxide–gold film on glassy carbon electrode and its electrocatalytic activity toward nitrite and hydrogen peroxide, Sens. Actuators B 198 (2014) 55–61. [17] J.N. Barisci, G.G. Wallace, Detection of nitrite using electrodes modified with an electrodeposited ruthenium-containing polymer, Anal. Lett. 24 (1991) 2059–2073. [18] A.C. Chen, S. Chatterjee, Nanomaterials based electrochemical sensors for biomedical applications, Chem. Soc. Rev. 42 (2013) 5425–5438.

49

[19] F.W. Campbell, R.G. Compton, The use of nanoparticles in electroanalysis: an updated review, Anal. Bioanal. Chem. 396 (2010) 241–259. [20] M. Govindhan, B.R. Adhikari, A.C. Chen, Nanomaterials-based electrochemical detection of chemical contaminants, RSC Adv. 4 (2014) 63741–63760. [21] Y. Liu, J. Zhou, J. Gong, W.P. Wu, V. Bao, Z.Q. Pan, H.Y. Gu, The investigation of electrochemical properties for Fe3 O4 @Pt nanocomposites and an enhancement sensing for nitrite, Electrochim. Acta 111 (2013) 876–887. [22] F.F. Liang, M.Z. Jia, J.B. Hu, Pt-implanted indium tin oxide electrodes and their amperometric sensor applications for nitrite and hydrogen peroxide, Electrochim. Acta 75 (2012) 414–419. [23] P. Miao, M. Shen, L.M. Ning, G.F. Chen, Y.M. Yin, Functionalization of platinum nanoparticles for electrochemical detection of nitrite, Anal. Bioanal. Chem. 399 (2011) 2407–2411. [24] P. Wang, F. Li, X. Huang, Y.X. Li, L. Wang, In situ electrodeposition of Pt nanoclusters on glassy carbon surface modified by monolayer choline film and their electrochemical applications, Electrochem. Commun. 10 (2008) 195–199. [25] A.K. Geim, K.S. Novoselov, The rise of graphene, Nat. Mater. 6 (2007) 183–191. [26] Z.Q. Yao, R.R. Yue, C.Y. Zhai, F.X. Jiang, H.W. Wang, Y.K. Du, C.Y. Wang, P. Yang, Electrochemical layer-by-layer fabrication of a novel three-dimensional Pt/graphene/carbon fiber electrode and its improved catalytic performance for methanol electrooxidation in alkaline medium, Int. J. Hydrog. Energy 38 (2013) 6368–6376. [27] T. Gan, S.S. Hu, Electrochemical sensors based on graphene materials, Microchim. Acta 175 (2011) 1–19. [28] S. Radhakrishnan, K. Krishnamoorthy, C. Sekar, J. Wilsonb, S.J. Kim, A highly sensitive electrochemical sensor for nitrite detection based on Fe2 O3 nanoparticles decorated reduced graphene oxide nanosheets, Appl. Catal. B 148/149 (2014) 22–28. [29] Y. Zhang, Y.H. Zhao, S.S. Yuan, H.G. Wang, C.D. He, Electrocatalysis and detection of nitrite on a reduced graphene/Pd nanocomposite modified glassy carbon electrode, Sens. Actuators B 185 (2013) 602–607. [30] V. Mani, A.P. Periasamy, S.M. Chen, Highly selective amperometric nitrite sensor based on chemically reduced graphene oxide modified electrode, Electrochem. Commun. 17 (2012) 75–78. [31] D. Zhang, Y. Fang, Z. Miao, M. Ma, X. Du, S. Takahashi, J. Anzai, Q. Chen, Direct electrodeposion of reduced graphene oxide and dendritic copper nanoclusters on glassy carbon electrode for electrochemical detection of nitrite, Electrochim. Acta 107 (2013) 656–663. [32] S.F. Jiao, J. Jin, L. Wang, One-pot preparation of Au–RGO/PDDA nanocomposites and their application for nitrite sensing, Sens. Actuators B 208 (2015) 36–42. [33] W.S. Hummers, R.E. Offeman, Preparation of graphitic oxide, J. Am. Chem. Soc. 80 (1958), 1339-1339. [34] B.B. Yang, H.W. Wang, J. Du, Y.Z. Fu, P. Yang, Y.K. Du, Direct electrodeposition of reduced graphene oxide on carbon fiber electrode for simultaneous determination of ascorbic acid, dopamine and uric acid, Colloids Surf. A 456 (2014) 146–152. [35] J.T. Chen, G.G. Zhang, B.M. Luo, D.F. Sun, X.B. Yan, Q.J. Xue, Surface amorphization and deoxygenation of graphene oxide paper by Ti ion implantation, Carbon 49 (2011) 3141–3147. [36] Z.Q. Yao, M.S. Zhu, F.X. Jiang, Y.K. Du, C.Y. Wang, P. Yang, Highly efficient electrocatalytic performance based on Pt nanoflowers modified reduced graphene oxide/carbon cloth electrode, J. Mater. Chem. 22 (2012) 13707–13713. [37] A. Das, B. Chakraborty, A.K. Sood, Raman spectroscopy of graphene on different substrates and influence of defects, Bull. Mater. Sci. 31 (2008) 579–584. [38] R.S. Dey, C.R. Raj, Development of an amperometric cholesterol biosensor based on graphene–Pt nanoparticle hybrid material, J. Phys. Chem. 114 (2010) 21427–21433. [39] D. Bin, F.F. Ren, H.W. Wang, K. Zhang, B.B. Yang, C.Y. Zhai, M.S. Zhu, P. Yang, Y.K. Du, Facile synthesis of PVP-assisted PtRu/RGO nanocomposites with high electrocatalytic performance for methanol oxidation, RSC Adv. 4 (2014) 39612–39618. [40] R. Liu, H.H. Zhou, J. Liu, Y. Yao, Z.Y. Huang, C.P. Fu, Y.F. Kuang, Preparation of Pd/MnO2 –reduced graphene oxide nanocomposite for methanol electrooxidation in alkaline media, Electrochem. Commun. 26 (2013) 63–66. [41] C. Xiao, X. Chu, Y. Yang, X. Li, X. Zhang, Hollow nitrogen-doped carbon microspheres pyrolyzed from self-polymerized dopamine and its application in simultaneous electrochemical determination of uric acid, ascorbic acid and dopamine, Biosens. Bioelectron. 26 (2011) 2934–2939. [42] J. Du, R.R. Yue, F.F. Ren, Z.Q. Yao, F.X. Jiang, P. Yang, Y.K. Du, Novel graphene flowers modified carbon fibers for simultaneous determination of ascorbic acid, dopamine and uric acid, Biosens. Bioelectron. 53 (2014) 220–224. [43] X. Cao, X.L. Cai, N. Wang, L. Guo, Hierarchical CuO nanochains: synthesis and their electrocatalytic determination of nitrite, Anal. Chim. Acta 691 (2011) 43–47. [44] S. Alwarappan, A. Erdem, C. Liu, C.Z. Li, Probing the electrochemical properties of graphene nanosheets for biosensing applications, J. Phys. Chem. 113 (2009) 8853–8857. [45] O. Brylev, M. Sarrazin, L. Roue, D. Belanger, Nitrate and nitrite electrocatalytic reduction on Rh-modified pyrolytic graphite electrodes, Electrochim. Acta 52 (2007) 6237–6247. [46] Y. Yue, G. Hu, M. Zheng, Y. Guo, J. Cao, S. Shao, A mesoporous carbon nanofibermodified pyrolytic graphite electrode used for the simultaneous determination of dopamine, uric acid, and ascorbic acid, Carbon 50 (2012) 107. [47] E. Laviron, General expression of the linear potential sweep voltammogram in the case of diffusionless electrochemical systems, J. Electroanal. Chem. 101 (1979) 19–28.

50

B. Yang et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 481 (2015) 43–50

[48] R. Guidelli, F. Pergola, G. Raspi, Voltammetric behavior of nitrite ion on platinum in neutral and weakly acidic media, Anal. Chem. 44 (1972) 745–755. [49] X.R. Li, F.Y. Kong, X.C. Liu, J.J. Xu, H.Y. Chen, Potassium-doped graphene for simultaneous determination of nitrite and sulfite in polluted water, Electrochem. Commun. 20 (2012) 109–112. [50] Y. Zhang, R. Yuan, Y.Q. Chai, W.J. Li, X. Zhong, H.A. Zhong, Simultaneous voltammetric determination for DA, AA and NO2 − based on graphene/polycyclodextrin/MWCNTs nanocomposite platform, Biosens. Bioelectron. 26 (2011) 3977–3980. [51] S.J. Li, G.Y. Zhao, R.X. Zhang, Y.L. Hou, L. Liu, H. Pang, A sensitive and selective nitrite sensor based on a glassy carbon electrode modified with gold nanoparticles and sulfonated graphene, Microchim. Acta 180 (2013) 821–827.

[52] W.J.R. Santos, A.L. Sousa, R.C.S. Luz, F.S. Damos, L.T. Kubota, A.A. Tanaka, S.M. Tanaka, Amperometric sensor for nitrite using a glassy carbon electrode modified with alternating layers of iron (III) tetra-(N-methyl-4-pyridyl)porphyrin and cobalt(II) tetrasulfonated phthalocyanine, Talanta 70 (2006) 588–594. [53] H. Mao, X.C. Liu, D.M. Chao, L.L. Cui, Y.X. Li, W.J. Zhang, C. Wang, Preparation of unique PEDOT nanorods with a couple of cuspate tips by reverse interfacial polymerization and their electrocatalytic application to detect nitrite, J. Mater. Chem. 20 (2010) 10277–10284. [54] C. Lin, X.M. Meng, M.R. Xu, K. Shang, S.Y. Ai, Y.P. Liu, Electro-oxidation nitrite based on copper calcined layered double hydroxide and gold nanoparticles modified glassy carbon electrode, Electrochim. Acta 56 (2011) 9769–9774.