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An XPS spectrum corresponding to N1s peak is shown Figure 5a. De convoluted spectra show that main peak is located at 400. 1 eV, whereas the peak located at 399. 39 eV corresponds to the binding energy of nitrogen atoms in C–N=C bonds. Figure 5b shows the two strong peaks at 931. 3 and 951. 2 eV correspond to the electron states of Cu2p3/2 and Cu2p1/2, respectively. Figure 5c shows the O1s peak of 532. 9 eV as compared to the XPS spectra of O1s of AF-MWCNTs (532. 1eV), the CuPc/MWCNTs peak slightly shifted to the low binding energy. This may be attributed to the formation of hydrogen bonds. It is clear from the results that a significant shift of the main peaks of CuPc has taken place in CuPc/MWCNT sample which ensures the proper attachment of CuPc on MWCNT. The SEM analysis shows that the nanocomposite CuPc/MWCNTs displays one-dimensional nanocrystals connected by MWCNTs. The variable size of MWCNT of 94. 1, 121, 126, 149, 188, 219 and 238 nm confirms the deposition of CuPc over MWCNT and present as a nanocomposite. The morphology, dimensions and orientation of CNTs can be easily revealed by using scanning electron microscopy (shown in Figure 6a [22-24]. B A C Fig. 6 SEM image of (a) CNT, (b) CuPc/MWCNT, (c) EDAX spectrum of CuPc/MWCNT Fig. 6 (A) Cyclic voltammogram for Bare GCE (a), NO2-/GCE (b) and CuPc-MWCNTGCE(c); B) The effect of concentration on oxidation of nitrite (range 0. 13 mM to 0. 66 mM) in 0. 1M Potassium Chloride solution . (C) The effect of scan rate for nitrite oxidation from 25-100 mV s-1 in KCl solution. (D) Differential pulse voltammogram for different concentration of nitrite ranging from 0. 6 mM to2. 3 mM in Potassium Chloride solution A higher magnified image of CuPc/MWCNT is shown in Figure 6b. For the clear understanding of the attachment, a closer view of the material which shows that the walls of each individual nanotube are coated with CuPc by varying thickness [16, 19]. The CuPc attachment over MWCNT increased the wall diameter of the nanotubes are 94. 1, 121, 126, 149, 188, 219, 238. The presence of each element in the CuPc/MWCNT samples was examined by using EDAX (Fig. 6c). The electrochemical behavior of CuPc/MWCNT nanoparticles was studied using 0. 1 M potassium chloride electrolyte and the resulting catalytic response is shown in Fig. 8. An oxidation peak of nitrite ion was detected at Ep = 0. 76 V and no cathodic current is observed in this potential range during the reverse cycle. The principal product formed in the first charge transfer reaction.
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