Electrochemical Oxidation Behavior Research Articles

Investigation of Electrochemical Oxidation Behaviors and Mechanism of Single-Crystal Silicon (100) Wafer under Potentiostatic Mode

Electrochemical oxidation (ECO) has been used widely to oxidize single crystal Si wafers. Aiming at optimizing the ECO assisted machining methods, the oxidation behaviors of single- crystal silicon (100) wafer under potentiostatic mode are experimentally investigated. It is shown that the Si wafer can be electrochemically oxidized and the oxidized film thickness reaches to 239.6 nanometers in 20 min. The hardness of the oxidized surface is reduced by more than 50 percent of the original surface. The results indicate that the oxide thickness and the hardness can be controlled by changing the voltage. Based on the experimental findings, a hypothesis on the ECO mechanism under potentiostatic mode was proposed to explain the fluctuations of current density under specific applied voltage. The occurrence of the multiple peaks in the current density curve during the oxidation process is due to the formation of discharge channels, which was initiated from the defects at the interface between the oxide bottom and the substrate. This breaks the electrical isolation and leads to the discontinuous growth of the electrochemical oxide layer. The present work contributes to the fundamental understanding of the ECO behaviors for the single-crystal Si (100) wafer under potentiostatic mode.

Enabling Stable Cycling of 4.2 V High‐Voltage All‐Solid‐State Batteries with PEO‐Based Solid Electrolyte

AbstractPoly(ethylene oxide) (PEO)‐based solid electrolytes are expected to be exploited in solid‐state batteries with high safety. Its narrow electrochemical window, however, limits the potential for high voltage and high energy density applications. Herein the electrochemical oxidation behavior of PEO and the failure mechanisms of LiCoO2‐PEO solid‐state batteries are studied. It is found that although for pure PEO it starts to oxidize at a voltage of above 3.9 V versus Li/Li+, the decomposition products have appropriate Li+ conductivity that unexpectedly form a relatively stable cathode electrolyte interphase (CEI) layer at the PEO and electrode interface. The performance degradation of the LiCoO2‐PEO battery originates from the strong oxidizing ability of LiCoO2 after delithiation at high voltages, which accelerates the decomposition of PEO and drives the self‐oxygen‐release of LiCoO2, leading to the unceasing growth of CEI and the destruction of the LiCoO2 surface. When LiCoO2 is well coated or a stable cathode LiMn0.7Fe0.3PO4 is used, a substantially improved electrochemical performance can be achieved, with 88.6% capacity retention after 50 cycles for Li1.4Al0.4Ti1.6(PO4)3 coated LiCoO2 and 90.3% capacity retention after 100 cycles for LiMn0.7Fe0.3PO4. The results suggest that, when paired with stable cathodes, the PEO‐based solid polymer electrolytes could be compatible with high voltage operation.

The Fabrication of a Highly Sensitive Nano Green Carbon Paste Electrode Modified with Yttrium Doped Manganese Oxide (Mn2O3/Y2O3) for Electrochemical Determination of Marbofloxacin and Its Residues in Bovine Meat and Milk Samples

In the present work, a novel sensitive electrochemical carbon paste electrode chemically modified with yttrium doped manganese oxide Mn2O3/Y2O3 nanostructures was assigned for determination of marbofloxacin (MRB) using square wave voltammetry (SWV) method. MRB has a broad spectrum of bactericidal activity for the treatment of urinary, respiratory and dermatological diseases in bovines and their retention in animal meats and milk leads to adverse side effects for the consumer. Thus a rapid estimation of minor concentrations of MRB has exerted a great concern to ensure food safety. XRD, EDX, Raman spectroscopy, SEM, and TEM techniques were employed to characterize the samples. The electrochemical oxidation behavior of MRB shows irreversible anodic peak at 1.10 V vs Ag/AgCl, in Britton–Robinson buffer (BR) at pH 5.0. The relationship was rectilinear over the range 10 × 10−9–1.0 × 10−4 M between the peak current and its related concentration with a minimum detection limit of 2.4 × 10−9 M. The developed method was green chemistry challenges and successfully applied to assay the drug in its dosage form, bovine meat and milk samples with a good recovery lies between 94.56% and 105.33% with relative standard deviation less than 10%.

Novel polyimides containing flexible carbazole blocks with electrochromic and electrofluorescencechromic properties.

A series of polyimides (PIs) were prepared by polycondensation of a diamine monomer with five anhydrides (1,2,4,5-benzenetetracarboxylic anhydride (BTA), 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTD), 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BTD), 4-[(1,3-dihydro-1,3-dioxo-5-isobenzofuranyl)oxy]-1,3-isobenzofurandione (DDII), and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BPTD)), which have anodic electrochromic (EC) properties. These PIs not only show good solubility and thermal stability, but also demonstrate stable electrochemical oxidation behavior and good EC properties, and the highest retained electroactivity reaches 99% after 600 cycles. In addition, the series of PIs exhibit excellent electrofluorescencechromic (EFC) properties. Therefore, the novel materials will contribute to the application of EC or EFC displays in the future.

A Carbon Paste Electrode Modified by Graphene Oxide/Fe3O4@SiO2/Ionic Liquid Nanocomposite for Voltammetric Determination of Acetaminophen in the Presence of Tyrosine

Herein, we introduce a novel modification process for carbon paste electrode by magnetic core–shell nanocomposite of graphene oxide/Fe3O4@SiO2 and n-hexyl-3-methylimidazolium hexafluoro phosphate as ionic liquid. Electrochemical features of this modified carbon paste electrode and its performance evaluation in simultaneous detection of acetaminophen and tyrosine via voltammetric oxidation was investigated. Moreover, diagnostic techniques including cyclic voltammetry, square wave voltammetry and chronoamperometry were applied in order to study the electrochemical oxidation behavior of this sensor toward acetaminophen. According to square wave voltammetry results, linear dynamic range between 1.0 × 10–6–1.0 × 10–3 M was observed for acetaminophen. The function of modified electrode in real samples containing acetaminophen and tyrosine was satisfactory.

Investigation into electrochemical oxidation behavior of 4H-SiC with varying anodizing conditions

Electrochemical-assisted hybrid machining has been widely utilized for processing of single crystal SiC, which is a very promising next-generation semiconductor material for high power, high frequency and high temperature applications. With the aim of optimizing the machining process to achieve both high efficiency and high surface integrity, the electrochemical oxidation behaviors of 4H-SiC were experimentally investigated with varying the anodizing conditions from the aspects of electrolyte types, ionic concentration, potentials etc. in this study. Experimental results demonstrated that neutral solutions showed higher oxidation ability of 4H-SiC in comparison to acidic and alkaline electrolytes. 4H-SiC could be electrochemically oxidized in an extremely low concentration electrolyte, and mass concentration 1–2% could achieve highest film thickness of 197 nm and initial oxidation rate of 4.9 nm/s. The oxidation rate increased exponentially at the initial stage of anodization before reaching saturation. Meanwhile, the oxidation process exhibited significant anisotropy, with the oxidation rate of C-face 5–15 times higher that of Si-face. On the other hand, the hardness of the electrochemically-oxidized 4H-SiC surface was reduced by more than 90%. It was also noticed that the micro morphology of oxidized surface was significantly influenced by the ion types in the electrolytes. Furthermore, the electrochemical oxidation mechanism of 4H-SiC were discussed based on the experimental findings. The OH. radical was considered the main factor determining the oxidation process of SiC. The research results deepen the understanding of the electrochemical oxidation of SiC and provide insights for optimizing the electrochemical-assisted hybrid machining process.

Electrochemical Oxidative Determination and Electrochemical Behavior of 4‐Nitrophenol Based on an Au Electrode Modified with Electro‐polymerized 3,5‐Diamino‐1,2,4‐triazole Film

AbstractA simple and fast electrochemical method was described and evaluated to determine the hazardous compound, 4‐nitrophenol (4NP). In this work, concentration of 4NP was determined by differential wave voltammetry (DPV). A gold electrode (Au) was modified with 3,5‐diamino‐1,2,4‐triazole (35DT). The modified electrode (35DT‐Au) was characterized by using electrochemical impedance spectroscopy (EIS), fouirer transform infrared spektrofotometre (FTIR), cyclic voltammetry (CV) and DPV. The modified electrode showed more sensitivity towards 4NP compared to unmodified one. A wide linear concentration range from 0.24 to 130.6 μM was obtained for 4NP with a detection limit of 0.09 μM. In the reproducibility and repeatability studies, the relative standard deviation (RSD%) values of the method were obtained as 3.72 % and 2.56 %, respectively, which are acceptable values. This proposed method was successfully used for the analysis of 4NP in lake and tap water samples. Simplicity, sensitivity, selectivity and high efficiency of the proposed method can be used in routine analysis of trace amounts of 4NP in polluted waters.

Amperometric detection of glucose based on immobilizing glucose oxidase on g-C3N4 nanosheets

2-dimensional graphitic carbon nitride (g-C3N4) nanosheets were synthesized from thiourea and urea through hydrothermal method, which was confirmed by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, atomic force microscopy (AFM), and electrochemical techniques. Excellent biocompatibility of g-C3N4 makes its suitable for the sufficient immobilization of glucose oxidase with improved catalytic behavior. The electrochemical oxidation behavior of glucose was chosen as the model to study the sensing performance of GOx/g-C3N4 nanocomposite modified glassy carbon electrode in neutral condition. Several impact factors, such as the mixing ratio of g-C3N4 and GOx, the modified amount of GOx/g-C3N4 suspension, the applied potential, and the pH values, were investigated. Under the optimal condition, glucose can be linearly detected in the range of 50 μM to 2 mM with the sensitivity of 21.7 μA mM−1 cm−2. The detection limit was evaluated as 5 μM with the signal-to-noise ratio of 3. The modified electrode exhibited good reproducibility and long-term stability, which is applicable for the detection of glucose in real samples.

Studies on Electrochemical Generation of Ceric Ions in Nitric Acid Medium

AbstractCerous/ceric redox couple is considered as a potential Mediated Electro Oxidative (MEO) catalyst in the electro‐oxidative dissolution of difficult‐to‐dissolve trans‐uranic elements in the concentrated nitric acid medium. The electrochemical oxidation behavior of CeIII in 11.5 M HNO3 was investigated by cyclic voltammetry (CV) using two different working electrodes platinum (Pt) and glassy carbon (GC) at 298 K. At higher acidity, cerous to ceric oxidation on GC working electrode was found to be a reversible process contrary to a quasi‐reversible observed at Pt working electrode. To compare the current efficiency in electrochemical cells for the oxidation of CeIII ions, lab and bench scale oxidation of 0.05 and 0.5 M CeIII in 11.5 M nitric acid was performed in divided and undivided cell assemblies using Pt electroplated Ti (PET) or pure Pt gauze as anodes. Almost 100% yield for CeIV could be achieved in divided cells and under identical conditions; the conversion efficiency was 30% lower in undivided cells. These studies revealed the concentration dependence of CeIII besides cell potential and temperature on the rate of oxidation.

In Situ Electrochemical Mapping of Lithium–Sulfur Battery Interfaces Using AFM–SECM

Although lithium-sulfur (Li-S) batteries are explored extensively, several features of the lithium polysulfides (LiPS) redox mechanism at the electrode/electrolyte interface still remain unclear. Though various in situ and ex situ characterization techniques have been deployed in recent years, many spatial aspects related to the local electrochemical phenomena of the Li-S electrode are not elucidated. Herein, we introduce the atomic-force-microscopy-based scanning electrochemical microscopy (AFM-SECM) technique to study the Li-S interfacial redox reactions at nanoscale spatial resolution in real time. In situ electrochemical and alternating current (AC) phase mappings of Li2S particle during oxidation directly distinguished the presence of both conducting and insulating regions within itself. During charging, the conducting part undergoes dissolution, whereas the insulating part, predominantly Li2S, chemically/electrochemically reacts with intermediate LiPS. At higher oxidation potentials, as-reacted LiPS turns into insulating products, which accumulate over cycling, resulting in reduction of active material utilization and ultimately leading to capacity fade. The interdependence of the topography and electrochemical oxidative behavior of Li2S on the carbon surface by AFM-SECM reveals the Li2S morphology-activity relationship and provides new insights into the capacity fading mechanism in Li-S batteries.

Correlated Anodic-Cathodic Nanocollision Events Reveal Redox Behaviors of Single Silver Nanoparticles.

We reported a novel method to real-time monitor the redox behaviors of single Ag nanoparticles (AgNPs) at a Au ultramicroelectrode between oxidizing and reducing pulse potentials using the nanocollision electrochemical method. At fast pulse potentials, the instantaneous anodic-cathodic current transients of a single AgNP were observed for the electrooxidation of AgNP, followed by the electroreduction of the newborn silver oxide (AgO) NP in alkaline media via switching of redox potentials; however, only anodic oxidation signals of individual AgNPs were observed in neutral solution. Through this study, we have revealed the substantial different dynamic nanocollision electrochemical behaviors of single AgNPs on the electrode surface in various media. Our study offers a new view for clearly clarifying in situ tracking of the electron-transfer process of single NPs by correlating electrochemical oxidation and reduction behaviors with the complementary information.

Direct Liquid Fuel Cells By Using Hypophosphites

Direct liquid fuel cells (DLFCs) are promising power sources for future portable, wearable or implantable electronic devices owing to their high energy density and low emissions. Large efforts have been given for the development of DLFCs since 1990s, however the wide spread commercialization of DLFCs is still limited by the high cost coming from the expensive noble metal catalysts and proton exchange membranes. Furthermore, the safety risks related to organic fuels (methanol, ethanol and formic acid), such as toxicity and flammability, bring up tremendous consideration in fuel cell design, fuel distribution and transportation [1]. Finally, the emission of CO2 is inevitable by using organic fuels, which escalates to Green House Effect. In this work, we proposed a new category of inorganic fuels for DLFCs. Hypophosphite is a type of food additive, therefore no safety hazards at all, and is also a strong reductant whose electrochemical oxidation reactivity is strongly correlated to metallic palladium [2]. Moreover, the inorganic fuels could realize “Zero Emission” after “Burning”. From thermodynamic calculations, the theoretical cell voltage and volumetric energy density at 1M are 2.05 V and 188 Wh/L at standard conditions, which are comparable and even better than the data of DMFCs (Direct Methanol Fuel Cells). The unique electrochemical oxidation behavior of hypophosphites on Pd catalyst brings advantages in simplifying fuel cell structure and broadening our selections of cathodic catalysts for ORR (Oxygen Reduction Reaction). Herein, we report the investigation of catalyst design and cell design of a novel membrane-free Direct Hypophosphite Fuel Cell (DHPFC), which showed an open circuit voltage of 1.0 V and a maximum power density of 32 mW cm-2 under air flow at 25 oC. The oxidation mechanism of hypophosphites on Pd was also studied in this work. This work is financially sponsored by Solvay and “Shanghai Rising-Star Program” (16QB1404600). Reference: [1] G. L. Soloveichik, Beilstein J. Nanotechnol. 2014, 5, 1399-1418. [2] N. Fujiwara, Z. Siroma, T. Ioroi, K. Yasuda, J. Power Sources 2007, 164, 457-463.

Cephalosporin Antibiotics: Electrochemical Fingerprints and Core Structure Reactions Investigated by LC-MS/MS.

Electrochemistry and exploiting electrochemical fingerprints is a potent approach to address newly emerging surveillance needs, for instance, for antibiotics. However, a comprehensive insight into the electrochemical oxidation behavior and mechanism is required for this sensing strategy. To address the lack of knowledge of the voltammetric behavior of the cephalosporin antibiotics, a selection of cephalosporin antibiotics and two main intermediates were subjected to an electrochemical study of their redox behavior by means of pulsed voltammetric techniques and small-scale electrolysis combined with HPLC-MS/MS analyses. Surprisingly, the detected oxidation products did not fit the earlier suggested oxidation of the sulfur group to the corresponding sulfoxide. The influence of different side chains, both at the three and seven position of the β-lactam core structure on the electrochemical fingerprint, were investigated. Additional oxidation signals at lower potentials were elucidated and linked to different side chains. These signals were further exploited to allow simultaneous detection of different cephalosporins in one voltammetric sweep. These fundamental insights can become the building blocks for a new on-site screening method.

Anion effects on the solvation structure and properties of imide lithium salt-based electrolytes.

The anion effect on Li+ solvation structure and consequent electrochemical and physical properties was studied on the basis of LiFSI-DMC (lithium bisfluorosulfonyl imide-dimethyl carbonate)- and LiTFSI-DMC (lithium bis(trifluoromethanesulfonyl imide)-dimethyl carbonate)-based dilute electrolytes, highly concentrated electrolytes, and localized concentrated electrolytes. With different anions, the electrolytes are different in possible solvation structures and charge distributions, leading to differences in terms of thermal properties, viscosity, ionic conductivity, electrochemical oxidation and reduction behaviors as well as LiNi0.6Mn0.2Co0.2|Li cell performances. The results indicate that the electronic structure of anions contributes greatly to the charge distribution of the Li+ solvation sheath, and consequently extends to the thermodynamics of the carbonate molecules, affecting reduction, oxidation reaction and products on the interface between electrolytes and electrodes. The comprehensive understanding of the solution structure and properties is necessary for the rational design of advanced electrolytes.

Versatile Sensor Modified with Gold Nanoparticles Carbon Paste Electrode for Anodic Stripping Determination of Brexpiprazole: A Voltammetric Study

A variety of voltammetric methods have been carried out for determination of brexpiprazole (BRX) using cyclic voltammetry (CV) and two different type anodic stripping methods; differential pulse (AS-DP) and square wave (AS-SWV) at modified carbon paste electrode with gold nanoparticles (AuNPs-CPEs). Additionally, electrochemical impedance spectroscopy (EIS) technique has been utilized for characterization of the different electrodes. Electrochemical oxidation behavior of BRX shows an irreversible anodic peak at 0.88 V versus Ag/AgCl, in Britton–Robinson buffer (BR) at pH 4.0, 50s preconcentration time and −0.5 deposition potential. Rectilinear relationship between the peak current versus concentration was obtained over the ranges of 1.32 × 10−6–6.45 × 10−6 and 1.32 × 10−7– 6.45 × 10−7 mol L−1 for AS-DP and AS-SWV respectively. The lowest concentration that can be detected for both for AS-DP and AS-SWV was 3.99 × 10−7 and 3.32 × 10−8 mol L−1 respectively; the utilized methods have been devoted adequately for the estimation of BRX in its pure and dosage form.

Electrochemical Determination of Serotonin Using Pre‐treated Multi‐walled Carbon Nanotube‐polyaniline Composite Electrode

AbstractIn this study, the multiwalled carbon nanotube‐poly (aniline) (MWCNT‐PANI) composite is successfully deposited on the glassy carbon electrode (GCE) by electropolymerization as an efficient and conventional route. The structural and chemical properties of the MWCNT‐PANI was investigated by various spectroscopic and analytical techniques, scanning electron microscopy (SEM), X‐Ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). After that, the electrochemical oxidation behavior of serotonin (5‐HT) in phosphate buffer solution (pH 7.4) was examined using cyclic voltammetry (CV). Besides, the MWCNT‐PANI/GCE used for the detection of 5‐HT with linear concentration range (1.0×10−7–1.2×10−5 mol L−1), low limit of detection (3.3×10−8 mol L−1) under differential pulse voltammetric (DPV) conditions. The proposed electrochemical sensor based on MWCNT‐PANI is both time and cost effective, has good reproducibility, high selectivity as well as stability for 5‐HT determination. The developed composite electrode was used to detect 5‐HT in synthetic urine sample and satisfactory results were obtained with high recoveries.

Study on Electrochemical Oxidation of m-Nitrophenol on Various Electrodes Using Cyclic Voltammetry

The electrochemical oxidation behavior of m-nitrophenol (m-NP) was studied comparatively on glassy carbon electrode, Pt electrode, PbO2 electrode, SnO2 electrode, and graphite electrode using cyclic voltammetry. The cyclic voltammetry measurements were performed in acidic (1 M H2SO4, pH 0.4), neutral (1 M Na2SO4, pH 6.8), and alkaline (1 M NaOH, pH 12.0) media to investigate the effect of pH value on the oxidation of m-NP. The fouling of electrodes was also studied during cyclic voltammetry measurements. The results indicate that both of the electrode material and the pH value of supporting electrolyte had a significant influence on the oxidation of m-NP. In acidic medium, m-NP was irreversibly oxidized on glassy carbon electrode, Pt electrode, SnO2 electrode, and graphite electrode at 1.23, 1.26, 1.26 and 1.27 V, respectively, while there was no any oxidation peak for PbO2 electrode. In a neutral medium, m-NP yielded well-defined oxidation peaks on all electrodes, although the height and potential of the peaks depended on the material of electrodes. In the alkaline medium, the m-NP could be directly oxidized only on glassy carbon electrode and graphite electrode, but their peaks were not well defined because the oxidation of m-NP occurs closer to oxygen evolution potential region. In addition, the oxidation peaks appeared at the lower potential value in the alkaline medium than in neutral and acidic media. Under all conditions, except in the alkaline solution and on glassy carbon electrode, the passivation of electrodes occurred during continual scans.

Facile electrochemical synthesis of three dimensional flowerlike gold microstructure for electrochemical oxidation of hydrogen peroxide

In the present work, we report a simple and facile templateless electrodeposition of hierarchical flowerlike gold microstructure which was synthesized by using a chronoamperometric (CA) i–t curve technique at a constant applied potential of E = 0.5 V with respect to sat Ag/AgCl (KCl) on indium tin oxide electrode (ITO) substrate. The surface morphology, elemental composition and the preferred orientation of gold microflowers (AuMFs) were characterized using scanning electron microscopy (SEM) and X–ray photoelectron spectroscopy (XPS) analyses. The SEM images of the as-prepared AuMFs resembled nanoflakes which are building block for the formation of a three dimensional hierarchical flower–like morphology. Surface elemental composition and valence state of AuMFs is further examined by X–ray photoelectron spectroscopy (XPS). The electrochemical oxidation behavior of AuMFs was investigated by using Cyclic Voltammetry (CV) and chronoamperometric CA techniques with the H2O2 analyst in 0.1 M phosphate buffer solution (pH 7.4). The AuMFs deposited ITO electrodes exhibited excellent electrocatalytic reactivity towards H2O2 oxidation due to the increase of in adsorption of H2O2 on gold–oxide surfaces and it was enhancing the amperometric sensing of H2O2 in neutral solutions.

Determination of the Anti‐HIV Drug Nevirapine Using Electroactive 2D Material Pd@rGO Decorated with MoS2 Quantum Dots

AbstractHerein we report the detection of an anti‐HIV drug Nevirapine (NVP) through a sensitive electrochemical method using efficient electro‐active 2D materials; Palladium nanoparticles supported reduced graphene oxide (rGO), i.e., Pd@rGO, MoS2 quantum dots (QDs) and Pd@rGO decorated with MoS2 QDs modified electrodes. We have shown an interaction between Pd@rGO and MoS2 QDs in the composite based on FT‐IR and UV‐Vis. absorption studies. The interaction between Pd@rGO and MoS2 QDs in designed material leads to highly efficient electro‐activity that is actually responsible for the broad spectrum quantification of frequently used anti‐HIV drug Nevirapine. The electrochemical oxidation behaviour of NVP is studied using cyclic voltammetry (CV) over bare glassy carbon electrode and modified electrodes with alone Pd@rGO and MoS2 QDs and finally over designed material Pd@rGO/ MoS2 QDs. The excellent catalytic effect is observed over designed material as evident from oxidation at relatively lower potential of 0.65 V vs. Ag/AgCl and large peak current in comparison with others. Pd@rGO/ MoS2 QDs modified electrode exhibits a linear increase in oxidation peak current with an increase in NVP concentration in the range of 0.1 – 80 μM with limit of detection (LOD) of 50 nM at signal‐to‐noise ratio (S/N): 3. The developed sensing platform shows excellent stability and sensitivity to make it suitable for the determination of NVP in the complex system.

An Innovative Electrochemical Sensor Ground on NiO Nanoparticles and Multi-Walled Carbon Nanotubes for Quantitative Determination of Nitrite.

An electrochemical sensor ground on nickel oxide (NiO) nanoparticles and multi-walled carbon nanotubes (MWCNTs) was exploited for the detection of nitrite. Scanning electron microscopy (SEM) ensure the morphology of the nanocomposite consisted of NiO nanoparticle and MWCNTs. High Resolution Transmission electron microscopy (HR-TEM) reveals that the structure of NiO nanoparticles and MWCNTs. Scanning transmission electron microscopy (STEM) persuasively verified presence of the C, Ni and O element. The electrochemical character of the nanocomposite were researched by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and the behavior of electrochemical oxidation to nitrite on NiO/MWCNTs/CP was explored by chronoamperometry. In tests, the NiO/MWCNTs/CP shown a sensitive current response toward nitrite, the oxidation peak current are linearly related to nitrite concentration in the range from 10-6 M to 10-4 M (R = 0.997) with a sensitivity of 3.53 μA μM-1 and a detection limit of 0.25 μM (S/N = 3). The validity of utilizing the proposed electrode to determine nitrite in tap water was also demonstrated.