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  • Voltammetric determination of bilirubin on disposable screen printed carbon electrode
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-12
    Jeethu Raveendran, John Stanley, T.G. Satheesh Babu

    Disposable screen printed carbon electrodes have been developed for the quantitative determination of free bilirubin. The electrodes were fabricated using graphite carbon ink and characterized with microscopy, spectroscopy and diffraction studies. The carbon ink for printing is made of graphite nanoparticles of size around 50 nm. Electrochemical oxidation of bilirubin was carried out voltammetrically in Trizma buffer of pH 8.5. The sensor showed a dynamic detection range of 5–600 μM and a sensitivity of 95 μAμM−1 cm−2. The SPCE showed superior performance than many of the reported sensors in terms of dynamic range, sensitivity and oxidation potential. Molecules such as ascorbic acid, uric acid, dopamine, glucose, creatinine and ethanol were tested using SPCE and found to be non interfering with the detection of creatinine in the physiological conditions. The sensor was tested using bilirubin spiked serum samples and found that it is giving response to free bilirubin. The sensor was also used to study the affinity of free bilirubin to albumin and displacement of bilirubin from albumin by ibuprofen.

    更新日期:2018-04-17
  • Electrochemical synthesis of polyaniline-exfoliated graphene composite films and their capacitance properties
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-12
    Abdelfetteh Sayah, Farid Habelhames, Ahmed Bahloul, Belkacem Nessark, Yvan Bonnassieux, Denis Tendelier, Mohamed El Jouad

    In this work, the graphene was synthesized by electrochemical exfoliation method, which was used to prepare the polyaniline-graphene composite film (PANI-GR) onto fluorine doped tin oxide (FTO) electrode by chronoamperometry technic at monomer oxidation potential 0.8 V vs. SCE. During the electropolymerization, the incorporation of the synthetized graphene into polyaniline matrix was assured by agitation of the electrolyte (10−2 M Ani/1 M H2SO4) containing different mass of graphene (1, 2 and 3 mg). By taking the advantages of the high conductivity of GR and the pseudocapacitance of PANI, the FTO/PANI-GR composite film was taken as an example for the application to the supercapacitor electrode materials. The morphology and structure of FTO/PANI and FTO/PANI-GR were characterized by different technics SEM, XRD, FTIR, Raman spectroscopy and UV–visible spectroscopy. The electrochemical performance was evaluated by cyclic voltammetry, galvanostatic charge-discharge tests and electrochemical impedance spectroscopy (EIS). The obtained specific capacitance for the PANI material alone is about 176.29 F g−1 this value was increased up to 305.57 F g−1 for the composite film PANI-GR 3 mg at 5 mV s−1.

    更新日期:2018-04-17
  • In situ encapsulation of tin oxide and cobalt oxide composite in porous carbon for high-performance energy storage applications
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-11
    Bhupender Pal, Syam G. Krishnan, Bincy Lathakumary Vijayan, Midhun Harilal, Chun-Chen Yang, Fabian I. Ezema, Mashitah Mohd Yusoff, Rajan Jose

    Herein, we report the preparation of porous carbon from palm kernel shell and loading of tin oxide‑cobalt oxide in its pores using a facile in-situ encapsulation synthesis strategy. The as-synthesized SnO2/Co3O4@C composite was characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy and field-emission scanning electron microscopy techniques. Electrochemical charge storage capabilities of the composite were measured using cyclic voltammetry, charge-discharge cycling and electrochemical impedance spectroscopy in aqueous 6 M KOH and 1 M Na2SO4 electrolytes. The SnO2/Co3O4@C composite showed over 70% higher specific capacitance (177 F g−1) than the pure porous carbon (106 F g−1) in 6 M KOH. Among these electrolytes, the composite exhibited an enhanced electrochemical performance in KOH electrolyte due to its smaller hydrated ion radius, high ionic mobility and lower equivalent series resistance than Na2SO4.

    更新日期:2018-04-11
  • Biomineralization-mimetic preparation of robust metal-organic frameworks biocomposites film with high enzyme load for electrochemical biosensing
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-10
    Qi Zhang, Lin Zhang, Huang Dai, Zhishang Li, Yingchun Fu, Yanbin Li

    Inspired by biomineralization, we propose robust enzyme-metal-organic-frameworks (MOFs) biocomposites to fabricate ultra-stable modified-electrode for electrochemical biosensing. Glucose oxidase (GOx) and zeolitic imidazolate framework-8 (ZIF-8) were adopted as model enzyme and MOFs to illustrate and examine the proposed concept. The biocomposites could be readily prepared by mixing GOx and precursors of MOFs. The biomineralization-assisted in-situ entrapment method facilitated the formation of the biocomposites and endowed the biocomposites with high load of enzyme of 89%. The biocomposite film on the Au electrode also benefited the mass transfer efficiency due to its superior porosity. Accordingly, the modified electrodes worked well both at the first and second generation biosensing modes for the detection of glucose, exhibited satisfactory sensitivity, as well as detection limit down to micromolar level, which is comparable with or better than analogues. More specially, taking advantages of the biomineralization-mimetic effect, the in-situ encapsulation method, and the rigid frameworks of MOFs, the biocomposite film-modified electrode presented superior stability towards repeated electrochemical scanning (200 cycles), high temperature of 90 °C, organic solvents (acetone), and storage (almost no response lost for >50 days). The biosensor also presented satisfactory selectivity and feasibility for detection in red wine. The proposed modified-electrode might be promising as robust detection tool in different conditions, and the proposed biomineralization-inspired method should contribute to the development of multi-functional composite materials.

    更新日期:2018-04-10
  • Electrochemical behavior of lithium ion capacitor under low temperature
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-10
    Jin Zhang, Jing Wang, Zhiqiang Shi, Zhiwei Xu

    Lithium-ion capacitor (LIC) is a novel electrochemical energy storage device that bridges the performance gap between the electrical double-layer capacitor and lithium ion battery. In this work, we fabricated lithium-ion capacitors (LICs) with activated carbon (AC) positive electrode and pre-lithiated hard carbon (HC) negative electrode. The effect of low temperature on the electrochemical performance of LIC is investigated by the galvanostatic charging-discharging, electrochemical impedance tests, rate performance and cycle performance testing. The electrolyte viscosity increases, the ionic conductivity decreases and ionic migration becomes slow in the charge-discharge process with the decrease of temperature, causing the increase of resistance and the electrochemical polarization, which is responsible for the attenuation of LIC electrochemical performance. LIC at the temperature of −20 °C exhibits the optimal low temperature electrochemical performance, high energy density up to 76.6 Wh kg−1 and power density as high as 5.8 kW kg−1 (based on active material mass of two electrodes), excellent capacity retention of 80.1% after 5000 cycles.

    更新日期:2018-04-10
  • A facile horseradish peroxidase electrochemical biosensor with surface molecular imprinting based on polyaniline nanotubes
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-09
    Qin Wang, R. Xue, Hao Guo, Yuli Wei, Wu Yang

    A green, highly sensitive and selective electrochemical imprinted biosensor for horseradish peroxidase (HRP) was designed and prepared based on the combination of polyaniline nanotubes (PANTs) and self-assembly surface molecular imprinting technique. PANI nanotubes, as supporting material, could effectively enhance imprinting efficiency and the electrode conductivity and facilitate electron transfer. The imprinted biosensor was characterized by electrochemical methods, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). It showed a very highly electrocatalytical activity for reduction of hydrogen peroxide and could be used in amperometric determination of H2O2 in the ranges of 0–10 μM and 10–90 μM with a detection limit of 0.01 μM (S / N = 3). The imprinted sensor showed still an excellent selectivity for HRP and was successfully employed to detect different concentration levels of HRP from 1.0 × 10−9 to 0.10 mg/mL with a detection limit of 3.56 × 10−10 mg/mL(8.1fM) (S / N = 3) with Fe(CN)63/4− probe by differential pulse voltammetry(DPV). The developed method was successfully used in determination of H2O2 in human urine sample.

    更新日期:2018-04-09
  • CeO2-modified LaNi0.6Fe0.4O3 perovskite and MWCNT nanocomposite for electrocatalytic oxidation and detection of urea
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-06
    Thao Quynh Ngan Tran, Suk Won Yoon, Bang Ju Park, Hyon Hee Yoon

    A perovskite-type oxide (LaNi0.6Fe0.4O3-CeO2, LNF-C) and multiwalled carbon nanotube (MWCNT) composite was employed as a novel catalyst material for the electrochemical oxidation of urea in an amperometric urea sensor. The structural and morphological properties of the LNF-C/MWCNT nanocomposite were studied by X-ray diffraction and scanning electron microscopy. The Ni-based pervoskite exhibited higher electrocatalytic activity than a single NiO compound, and CeO2 further improved the activity and stability. The reaction of urea electrooxidation on LNF-C occurred via 6-electrons, and was a half-order reaction with respect to urea concentrations in alkaline solution, as observed by cyclic voltammetry studies. The LNF-C/MWCNT modified electrodes exhibited a sensitivity of 195.6 μAmM−1 cm−2 in a linear range from 25 to 670 μM of urea with a low detection limit (1 μM), fast response time (5 s), and good stability. In addition, the urea sensor demonstrated feasibility for urea analysis in real urine samples. The results indicated that the LNF-C/MWCNT composite could be used as an effient catalyst for the electro-oxidation of urea and electrode material for non-enzymatic urea sensors.

    更新日期:2018-04-06
  • Trace level detection of guanine and adenine and evaluation of damage to DNA using electro-synthesised ZnS@CdS core-shell quantum dots decorated graphene oxide nanocomposite
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-05
    Majid Arvand, Zahra Khoshkholgh, Shiva Hemmati

    Quantum dots owing to their unique properties have been the subject of extensive investigations in different areas of science and technology in the past two decades. In this study, preparation of the electrochemical sensor for the selective and sensitive determination of guanine (G) and adenine (A), two of the most important components of DNA and RNA, were investigated by modifying a glassy carbon electrode (GCE) with ZnS@CdS quantum dots and graphene oxide (GO). This sensor shows separated and well-defined peaks for A and G, by which one can determine these biological bases individually or simultaneously. The novel electrode showed linear responses towards G and A over the concentration range of 0.01 μM to 50 μM. Detection limit was determined as 1.45 and 1.81 nM according to signal to noise ratio (S/N = 3). Furthermore, the measurements of thermally denatured single-stranded DNA were carried out and the value of (G + C) / (A + T) of DNA was calculated as about 0.77 for various DNA samples. The proposed electrochemical sensor exhibited some advantages in terms of simplicity, rapidity, high sensitivity, good reproducibility and long-term stability. The relative standard deviation of the proposed system, obtained using A and G standards, were 2.7% and 1.5% for intra-day and 4.3% and 4.1% for inter-day precisions, respectively. The results demonstrated that the proposed electrochemical sensor not only provides a novel and sensitive approach to detecting purine bases, but also ascertained that the proposed electrochemical sensor can be profitable to evaluate DNA bases damage.

    更新日期:2018-04-06
  • Removal of nitrate from water by the electrocatalytic denitrification on the Cu-Bi electrode
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-05
    Weichun Gao, Lulu Gao, Dan Li, Kaituo Huang, Li Cui, Jing Meng, Jiyan Liang

    The Cu-Bi cathode was a new type of electrode in the field of electrocatalytic denitrification. The Cu-Bi electrode prepared by electrodeposition at the current density of 6 mA cm−2 was better. The Cu-Bi coating was compact and crystalline by the characterization of SEM, EDS and XRD. Reduction of nitrate was investigated on Cu-Bi cathodes and Ti/Ru-IrO2 anodes. For 100 mg L−1 NO3−-N, the highest NO3−-N removal rate of 87.5% was obtained at the current density of 6 mA cm−2 and in neutral electrolyte at 4 h. The removal of nitrate on Cu-Bi electrodes was better in neutral electrolyte, which didn't require additional acid or alkali to adjust pH. When the initial concentration of NO3−-N was 50 mg L−1, the effluent concentration of NO3−-N at 4 h was 7.175 mg L−1 lower than the level of drinking water on the standard of the World Health Organization (WHO, 10 mg L−1). The kinetic investigation showed that the reduction of nitrate on Cu-Bi displayed pseudo first-order kinetic behavior. The results of Cyclic Voltammetric (CV) measurements indicated that nitrate was reduced on the Cu-Bi electrode with the occurrence of the hydrogen evolution.

    更新日期:2018-04-06
  • Sodium-rich iron hexacyanoferrate with nickel doping as a high performance cathode for aqueous sodium ion batteries
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-05
    Jie Wang, Changhuan Mi, Ping Nie, Shengyang Dong, Shengyang Tang, Xiaogang Zhang

    Na-rich NaxFeFe(CN)6 (NFF) in terms of low cost and high theoretical capacity has been considered to be a potential cathode material for aqueous sodium ion batteries (SIBs). However, low sodium content, poor Columbic efficiency (CE) and rapid capacity degradation impede their practical application. Herein, the effect of low-level Ni doping in NFF as cathode materials in 1 M NaNO3 electrolyte has been investigated, which were synthesized via a citrate-assisted co-precipitation route. NFF substituted with 23% Ni2+ exhibited the best electrochemical behaviors, which delivers a discharge capacity of 105.9 mAh g−1 at 200 mA g−1 and 73.1% capacity retention over 1000 cycles with an average CE of 99.8% at 1000 mA g−1. A reversible capacity of 55.5 mAh g−1 can be obtained even at a high current density of 2000 mA g−1. The Ni substitution strategy was evidenced to be a scalable method to prepare promising cathode materials with excellent cycling stability for high-performance aqueous SIBs.

    更新日期:2018-04-06
  • Conditions for a nearly perfect match between pulse voltammetry and linear scan voltammetry
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-04
    Nicolas Fatouros, Denise Krulic

    It is formally shown that linear scan voltammetry for a reversible charge-transfer on redox and metal/metal-ion electrodes can be approximated with great precision using the forward individual current in differential pulse voltammetry with a ratio of 0.4 between the pulse duration and the period of the waveform. For redox electrodes the same is also possible using the forward current in square wave voltammetry. In each case, there is coincidence with the linear scan voltammogram for a constant pulse-to-step height ratio. The relevance of this new approach is discussed and an experimental application with the Ti(IV)/Ti(III) couple in 0.25 M H2C2O4 solution at the mercury drop electrode is presented.

    更新日期:2018-04-04
  • Square wave voltammetric quantitative determination of flavonoid luteolin in peanut hulls and Perilla based on Au NPs loaded boron nitride nanosheets
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-04
    Li Fu, Zhong Liu, Yong Huang, Guosong Lai, Huaiwei Zhang, Weitao Su, Jinhong Yu, Aiwu Wang, Cheng-Te Lin, Aimin Yu
    更新日期:2018-04-04
  • Electrochemical characterizations and reverse electrodialysis performance of hybrid anion exchange membranes for salinity gradient energy
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-04
    Jin Gi Hong, Tae-Won Park

    Reverse electrodialysis (RED) is a technique that utilizes the salinity gradient through ion exchange membranes to generate electrical power. In order to make this technology feasible, innovation is required to improve a critical subcomponent, the ion exchange membrane, especially in the selection of appropriate membrane materials and the design of proper RED membranes. This study presents a novel and cost-competitive method for the design of anion exchange membranes (AEMs) by organic-organic hybridization. The low-cost and charge-possessing polymer, poly (diallyldimethylammonium chloride) and poly (vinyl alcohol) (abbreviated as PDDA and PVA, respectively) are blended in different mass ratios to form an AEM. The effect of various PDDA loadings on the electrochemical characterizations of the membranes was investigated. The key properties such as electrical resistance, permselectivity and ion exchange capacity were found to be improved with increasing the mass blend ratio of PDDA. Specifically, the increase of PDDA mass ratio significantly decreased the level of membrane resistance, which majorly contributed to the performance of RED power generation: reached the maximum power density of 0.58 W/m2. Such fabrication method of AEMs may provide the feasible design strategy of potential ion exchange membranes for a viable RED energy conversion.

    更新日期:2018-04-04
  • Mechanism studies of hydrazine electro-oxidation by a platinum ultramicroelectrode: Effects of supporting electrolytes
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-04
    Guoqing Yue, Qiang Zeng, Jianzhi Huang, Lishi Wang

    The effects of the supporting electrolyte on electro-catalytic reaction of hydrazine hydrate (HH) were studied by a platinum ultramicroelectrode. We found that the H+ electric field generated during the catalytic process can partly hinder the reactants from participating in the catalytic reaction by using low concentration supporting electrolytes. It results in the final steady current value is less than the theoretical value. On the other hand, supporting electrolyte has a regulatory effect on both concentrations of N2H4 and N2H5+ (protonated HH) involved in catalytic reaction, which in turn affects the number of steady state currents and the value of each steady state current generated in the reaction. In this case, the effect of neutral salts did not change with concentration variations. By contrast, when different concentrations of sulfuric acid or sodium hydroxide are used as the electrolytes, the number of steady state currents and the value of each steady state current are mainly determined by the original and the later produced H+ concentration around the electrode; while the number of steady state current and the value of each steady state current are co-determined by the thermodynamic equilibrium and the thermodynamics of catalytic reaction of HH, and the H+ absorbability of solution with different concentrations and types of sodium phosphate buffer. Moreover, this work can also provide useful information for the choice of supporting electrolyte and catalytic potential in determination of HH concentration by amperometric method and in catalytic reaction with HH as the redox medium.

    更新日期:2018-04-04
  • Mesoporous spinel manganese zinc ferrite for high-performance supercapacitors
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-04
    Fatma M. Ismail, Mohamed Ramadan, Ahmed M. Abdellah, Ibrahim Ismail, Nageh K. Allam
    更新日期:2018-04-04
  • Electrochemical surface plasmon resonance as a probe of redox reactions at the ionic liquid|gold interface
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-04
    Naoya Nishi, Yoichi Ikeda, Tetsuo Sakka

    Electrochemical surface plasmon resonance (ESPR) has been employed as a probe of redox reactions at the interface between gold (Au) and ionic liquid (IL). Two redox couples, ferrocene (Fc)/Fc+ and (ferrocenylmethyl)trimethylammonium (FTA+)/FTA2+, and two ILs, trioctylmethylammonium bis(trifluoromethanesulfonyl)amide ([TOMA+][C1C1N−]) and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C4mim+][C1C1N−]) have been studied. In the ESPR measurements, the shift of the SPR angle has been recorded simultaneously with cyclic voltammogram (CV). It has been revealed that the SPR angle shift reproduces CV when the former is semi-differentiated or the latter is semi-integrated, and, therefore, that the ESPR response probes the surface concentration of redox couples at the IL|Au interface. Among the four combination of the two redox couples and the two ILs, the case for Fc/Fc+ in [TOMA+][C1C1N−] shows significantly greater ESPR response than the other three cases. A model has been established for the relationship between the SPR angle shift and the surface concentration of redox species. The model predicts that the SPR angle shift becomes pronounced with increasing DR/DO, the diffusion coefficient ratio of the reduced (R) and oxidized (O) species when the reduced species is initially dissolved in the IL as is the case for the present study. Significantly greater DR/DO for Fc/Fc+ in [TOMA+][C1C1N−] than the three other cases has been confirmed from the DR and DO measurements by CV with a microdisk electrode. The trend of the measured DR and DO values agrees with recent findings by researchers that small neutral solutes in ILs composed of large ions diffuse fast beyond the prediction of the Stokes-Einstein relation.

    更新日期:2018-04-04
  • A novel electrochemical ascorbic acid sensor based on branch-trunk Ag hierarchical nanostructures electrode
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-04
    Yan Zhang, Zhiquan Cai, Meiqiong Chen, Min Zhang, Peng Liu, Faliang Cheng

    A novel branch-trunk Ag hierarchical nanostructure was synthesized by hydrothermal synthesis combined with microwave-assisted synthesis with Te nanowire as template. The Te nanowire was synthesized via hydrothermal process. The branch-truck Ag hierarchical nanostructures were constructed on Te nanowires through via galvanic replacement reaction with Te nanowire as the sacrifice temple with microwave-assisted synthesis method. We further investigated the potential application of the obtained hierarchical nanostructures for ascorbic acid electrochemical sensor analysis. The results showed the as-prepared sensor exhibited a wide liner range with 0.17 μM to 1.80 mM (R = 0.999) and the detection limit was estimated to be 0.06 μM (S/N = 3). These results indicated the branch-truck Ag hierarchical nanostructures were an excellent candidate material for sensing application.

    更新日期:2018-04-04
  • 更新日期:2018-04-04
  • Fabrication of Pt-ZnO composite nanotube modified electrodes for the detection of H2O2
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-04-03
    Xiaolin Ke, Guodong Zhu, Yong Dai, Yuqing Shen, Jianmao Yang, Jianyun Liu

    Pt-ZnO nanotubes were synthesized by one-pot electrospinning polyacrylonitrile (PAN) and polyvinyl pyrrolidone (PVP) bipolymer in the presence of zinc acetate and chloroplatinic acid, followed by the calcination of nanofibers. The tubular structure of Pt-ZnO composite and the homogeneous distribution of Pt nanoparticles were confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray diffraction (XRD) characterization demonstrates that ZnO exhibits the hexagonal wurtzite structure, while Pt particles exist mainly in the form of cubic Pt. Zero valence Pt is confirmed by X-ray photo spectroscopy (XPS). Pt-ZnO drop-coated glassy carbon electrode (Pt-ZnO/GCE) was employed for the measurement of H2O2. The Pt/Zn molar ratio affects the catalytic activity to H2O2 reduction. Pt-ZnO/GCE with the Pt/Zn ratio of 1:3 displayed the best catalytic performance, and a corresponding linear relationship was obtained with H2O2 concentrations ranging from 2 × 10−5 M to 5 × 10−3 M (R2 = 0.9969). The limit of detection is 1.5 × 10−6 M (S/N ≥ 3). The electrospun-based Pt-ZnO nanotubes have a great potential for electrochemical sensing.

    更新日期:2018-04-04
  • l-Cysteine oxidation studied by rotating ring disk electrodes: Verification of reaction intermediates
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-30
    André H.B. Dourado, Rodrigo Queiroz, Paulo T.A. Sumodjo

    l-Cysteine (l-Cys) is an amino acid of high interest in the electrochemical field since it is one of the five electrochemically active amino acids. Due to the S atom on its side chain, this molecule presents the highest amount of possible oxidation states. The rotating ring disk electrode (RRDE) technique is a very useful method for the investigation of complex mechanisms, such as l-Cys oxidation, as it allows the identification of some intermediates. By rotating disk electrode (RDE), it was possible to observe that the adsorption of l-Cys onto Pt electrodes is influenced by mass transport. The chemical reaction was found to be reversible, while the charge transfer irreversible. The RRDE study facilitated the proposal of an electrochemical-chemical-electrochemical mechanism. The ring current was observed to be dependent on the quadratic of the potential applied to the disk electrode combined with the value of the rotation rate in a soft-model algorithm. The product of this chemical step was oxidized in two steps on the ring, with the first one including the generation of an adsorbed intermediate as the rate-limiting step.

    更新日期:2018-03-31
  • Surface and electrochemical characterization of aryl films grafted on polycrystalline copper from the diazonium compounds using the rotating disk electrode method
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-30
    Marek Mooste, Elo Kibena-Põldsepp, Margus Marandi, Leonard Matisen, Väino Sammelselg, Fetah I. Podvorica, Kaido Tammeveski
    更新日期:2018-03-30
  • Development of a novel electrochemical sensor based on electropolymerized molecularly imprinted polymer for selective detection of sodium lauryl sulfate in environmental waters and cosmetic products
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-29
    Soukaina Motia, Ioan Albert Tudor, L. Madalina Popescu, Roxana Mioara Piticescu, Benachir Bouchikhi, Nezha El Bari
    更新日期:2018-03-30
  • A novel and high sensitive MWCNTs-nickel carbide/hollow fiber-pencil graphite modified electrode for in situ ultra-trace analysis of bisphenol A
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-29
    Mohammad-Bagher Gholivand, Arezoo Akbari

    In this study a modified electrode based on hollow fiber-pencil graphite electrode (HF-PGE) was introduced for extraction and in-situ determination of low concentrations of bisphenol A (BPA) as a typical endocrine disruptor (ED) and cancer promoter using differential pulse voltammetry (DPV). Nickel carbide nanoparticle (Ni3C) and multi-walled carbon nanotube (MWCNTs) were used for HF modification. The fundamental factors affecting the extraction of analyte, including pH of aqueous phase, extraction time, and stirring speed were investigated. The relationship between the DPV signal and concentration was linear in the ranges of 0.6 nM to 0.01 μM and 0.01 to 4 μM (R2 = 0.9958, 0.9972) with limit of detection 0.13 nM. The applicability of the developed technique was tested by determination of BPA in real samples such as plastic drinking bottle and food package samples.

    更新日期:2018-03-30
  • 更新日期:2018-03-30
  • Synthesis of Au@Pt nanoflowers supported on graphene oxide for enhanced electrochemical sensing of dopamine
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-29
    Ziyin Yang, Xiaoli Liu, Xiaohui Zheng, Jianbin Zheng

    Au@Pt nanoflowers supported on graphene oxide (Au@Pt/GO) nanocomposites were synthesized for enhanced electrochemical sensing of dopamine (DA). Au@Pt/GO nanocomposites were synthesized through a facile wet-chemical co-reduction method and the nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrum (EDS), X-ray diffraction spectroscopy (XRD) and electrochemical techniques. SEM and TEM results showed that large numbers of Au@Pt nanoflowers with Au cores and Pt dendritic shells were distributed on the surface of GO sheets, which made Au@Pt/GO modified electrode exhibit an excellent performance toward DA detection with a wide linear range of 0.5 μM to 0.1775 mM, a high sensitivity of 329.0 μA mM−1 cm−2 and a low detection limit of 0.11 μM (S/N = 3). Moreover, the sensor also displayed good selectivity, accepted reproducibility and stability. Therefore, these results indicated that Au@Pt/GO nanocomposite was a promising sensing material for DA detection.

    更新日期:2018-03-30
  • Electrodeposition of copper oxides (CuxOy) from acetate bath
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-29
    Z. Mezine, A. Kadri, L. Hamadou, N. Benbrahim, A. Chaouchi

    Herein, we report the study of the electrodeposition of copper oxides mainly Cuprite (Cu2O), paramelaconite Cu4O3 and tenorite (CuO) from a slightly acidic Cu(II) acetate solution on indium-doped tin oxide (ITO) substrate. A formation mechanism was proposed based on the observation of a series of reaction intermediates. The potential domain where the electrodeposition of copper oxides (CuxOy) is possible was investigated. The nucleation mechanism of (Cu2O) during electrodeposition was studied as a function of Cu2+ concentrations and deposition potential by exploiting the electrochemical techniques such as cyclic voltammetry and chronoamperometry. This study enabled us to demonstrate that the nucleation process and the growth of dendrites obey the model of Scharifker and Hills 3D instantaneous under diffusion control. Morphological and structural characterizations of the electrodeposit are performed by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

    更新日期:2018-03-29
  • Electrochemical determination of nepafenac topically applied nonsteroidal anti-inflammatory drug using graphene nanoplatelets-carbon nanofibers modified glassy carbon electrode
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-29
    Biljana Nigović, Sandra Jurić, Ana Mornar

    Nepafenac is novel ophthalmic agents with a unique prodrug structure and superior corneal permeability to other currently available topical nonsteroidal anti-inflammatory drugs. A graphene nanoplatelets and carbon nanofibers modified glassy carbon electrode was developed and used as first electrochemical sensor for the determination of nepafenac. The effective combination of graphene and carbon nanofibers resulted in electrochemical sensor with large surface area, high sensitivity, good stability and selectivity. After method optimization, the square wave voltammograms, at a preconcentration time of 60 s, display two linear ranges of 4.0 × 10−6–1.5 × 10−5 M and 2.5 × 10−7–4.0 × 10−6 M for drug quantification with a detection limit of 6.3 × 10−8 M. The modified electrode was employed for fast assay of nepafenac in ophthalmic solution with satisfactory results and rapid run time of 66 s in comparison with previously reported analytical methods.

    更新日期:2018-03-29
  • Self-assembly of Fe2O3/ordered mesoporous carbons for high-performance lithium-ion batteries
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-29
    Liying Kang, Zhenglong Yang, Yanbin Xu, Wei Jiang, Feng Wang, Yanfeng Meng, Na Liu, Fenghua Liu, Shujiang Ding

    Fe2O3/ordered mesoporous carbons (OMCs) have been synthesized by a facile one-pot hydrothermal method via self-assembly process. The combination of OMCs and anchored Fe2O3 nanoparticles shows a synergistic effect which results in a kind of anode materials with enhanced electrochemical performance for lithium ion batteries. OMCs with highly porous mesostructure and good conductivity not only alleviate the problem of volume variation and agglomeration of Fe2O3, but shorten the diffusion pathway of Li+ ions, which efficiently overcomes the problem of rapid capacity loss of iron oxide. Moreover, appropriate loading amount of Fe2O3 nanoparticles is believed to be a key factor to enhance the capacity of anode materials. The materials deliver an excellent reversible capacity of 789 mAh g−1 at a current density of 100 mA g−1 after 120 cycles.

    更新日期:2018-03-29
  • Bisphenol A electrochemiluminescence sensor based on reduced graphene oxide-Bi2ZnS4 nanocomposite
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-28
    Yaoyu Wu, Zengyao Zheng, Jianying Yang, Yuejuan Lin, Xiaoshan Zhang, Yaowen Chen, Wenhua Gao
    更新日期:2018-03-29
  • 更新日期:2018-03-29
  • Non-enzymatic glucose sensing based on hierarchical platinum micro-/nanostructures
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-28
    Tobias Unmüssig, Andreas Weltin, Sebastian Urban, Patrick Daubinger, Gerald A. Urban, Jochen Kieninger

    Non-enzymatic glucose monitoring for biomedical applications asks for long-term stable and selective sensors at neutral pH. A hierarchical platinum micro-/nanostructured electrode along with a novel measurement scheme leads to increased sensitivity, selectivity and stability compared to state-of-the-art. The hierarchical electrode coating was applied by a scalable two-step process, which combined electrochemical deposition and colloidal synthesis to obtain a hierarchical structure with high surface roughness. This three-dimensional structure consists of a cauliflower-like platinum deposition, which is coated by a platinum nanowire network. Amperometric glucose measurements showed a 10,000-fold increase in sensitivity (473 μA cm−2 mM−1) compared to unmodified electrodes and linear behavior in the physiological range. The obtained sensitivities are among the highest values reported for non-enzymatic glucose sensors in neutral pH media. The hierarchical morphology provides a selectivity mechanism depending on the reaction kinetics, improving the selectivity for glucose in the presence of the interferent ascorbic acid 2000-fold. Selectivity was further enhanced by low-frequency electrochemical impedance spectroscopy (EIS). Chronoamperometric protocols were developed to achieve long-term stability and overcome the loss of sensitivity due to electrode poisoning. Using chronoamperometric protocols for both the amperometry and the EIS measurements improved stability significantly. The presented results make hierarchical platinum micro-/nanostructured electrodes a promising candidate for continuous glucose monitoring.

    更新日期:2018-03-28
  • A conventional symmetric biosupercapacitor based on rusticyanin modified gold electrodes
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-28
    Elena González-Arribas, Magnus Falk, Olga Aleksejeva, Sergey Bushnev, Paula Sebastián, Juan M. Feliu, Sergey Shleev
    更新日期:2018-03-28
  • Time and calcination temperature influence on the electrocatalytic efficiency of Ti/SnO2:Sb(5%),Gd(2%) electrodes towards the electrochemical oxidation of naphthalene
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-27
    Carlos F.C. Machado, Maria A. Gomes, Ronaldo S. Silva, Giancarlo R. Salazar-Banda, Katlin I.B. Eguiluz

    Produced water is the largest volume wastewater associated with petroleum and gas production. Due to its diverse composition and large volume, produced water treatment is very challenging in order to avoid permanent or significant damages to the environment. On the other hand, the anodic material stability and the electrocatalytic properties are crucial for improved pollutant degradation efficiencies in electrochemical wastewater treatment. Here, we report the development of Ti/SnO2:Sb(5%),Gd(2%) electrodes by the polymeric precursor method, also known as Pechini method, for use in naphthalene electro-oxidation. The influence of the calcination time and temperature in the electrodes synthesis was investigated focusing on obtain an enhanced material with improved efficiencies in naphthalene oxidation. Thus, the Ti/SnO2:Sb(5%),Gd(2%) electrodes were calcined at 350, 400 and 450 °C during 1, 2 and 3 h for each temperature. Both temperature and time presented influence on the electrode electrocatalytic efficiency during naphthalene degradation, with emphasis on the calcination temperature influence. The most efficient electrodes are those calcined at 400 °C for 2 h, which degrade around 97% of the pollutant and reduce 86% of total organic carbon after 2 h of electrolysis at 2.0 V versus reversible hydrogen electrode. Besides that, they present the greatest rate constant coefficient of k = 1.41 mol−1 L min−1 and the greatest voltammetric charge density (13.75 mC cm−2) according to cyclic voltammetry measurements. Additionally, all the synthetized electrodes show high physical and electrochemical stability.

    更新日期:2018-03-28
  • Oxidative dissolution of NiO in aqueous electrolyte: An impedance study
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-27
    Matteo Bonomo, Gaia Naponiello, Danilo Dini

    The present contribution reports on the analysis of the electrochemical properties of screen-printed nickel oxide (NiO) in aqueous electrolyte when NiO is in the configuration of thin film (thickness, l ≤ 7 μm). This type of NiO samples presents mesoscopic morphology. The latter characteristic combined to the intrinsic electroactivity of the oxide leads to the observation of proportionality between NiO thickness and current density. In particular, NiO undergoes two distinct processes of oxidation with reversible features in aqueous media. These redox processes occur in the solid state and, as such, involve mass/charge transfer between the NiO electrode and the electrolyte. On the other hand, the electrochemical oxidation of NiO is accompanied by the progressive chemical dissolution of the oxide when the latter is in the oxidized state. This is a consequence of the elevated content of stored charge on NiO surface when it interfaces a high polarity solvent like water. In the present work we have considered electrochemical impedance spectroscopy (EIS) for the investigation of the charge transfer/transport properties of NiO during the simultaneous occurrence of chemical and electrochemical processes. The study proposes models of electrical circuits for analyzing the interfacial phenomena involved in the aqueous oxidation of NiO.

    更新日期:2018-03-28
  • High-performance glucose biosensor based on green synthesized zinc oxide nanoparticle embedded nitrogen-doped carbon sheet
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-27
    Nallal Muthuchamy, Raji Atchudan, Thomas Nesakumar Jebakumar Immanuel Edison, Suguna Perumal, Yong Rok Lee
    更新日期:2018-03-28
  • Applicability of electrochemical technologies for removing and monitoring Pb2+ from soil and water
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-27
    Karyn N.O. Silva, Suelya S.M. Paiva, Fernanda L. Souza, D.R. Silva, Carlos A. Martínez-Huitle, Elisama V. Santos

    This work examines electrokinetic remediation (ER) processes for removing Pb2+ in contaminated soils. For this purpose, different cathodic supporting electrolytes (NaNO3 0.1 M, EDTA 0.1 M and citric acid 0.1 M) were used into the catholyte reservoir, while in the anodic compartment, a solution of NaNO3 0.1 M was used. Additionally, the application of direct current (DC) and reverse polarity (RP) for removing of Pb2+ from the soil was also evaluated. Regarding to results obtained in this study indicated that RP and citric acid favored an efficient electromigration of Pb2+, favoring its elimination from the soil. This behavior can be explained because the elimination of Pb2+ depended on the dissolution/precipitation ionic species as well as the pH in the soil, which were maintaining in different sections in the soil, contributing to maintain the pH conditions, by using RP and citric acid, promoting the lead elimination. In order to use a feasible approach for monitoring Pb2+ concentration, adsorptive stripping voltammetry (AdSV) technique was used, obtaining acceptable confidence and good sensitivity for the concentration of Pb2+ with LOD about 0.1 mg L−1. Phytotoxicity tests showed that the ER process could be useful as a treatment technique for reducing hazardous soil toxicity polluted with Pb2+. The results confirmed the significant reduction of the germination in the anodic and cathodic regions for ER by applying DC with NaNO3 and EDTA as cathodic solutions. However, high germination (60–80%) was obtained for ER by using NaNO3 and citric acid solutions in cathodic compartments by applying RP or DC, respectively. Finally, the effluent generated by ER technology, in each one of experiments, was treated by electrocoagulation with Al electrodes, obtaining complete removal of Pb2+ from liquid after 60 min.

    更新日期:2018-03-27
  • Thermodynamic aspects of bis(3‑sulfopropyl) disulfide and 3‑mercapto‑1‑propanesulfonic acid in Cu electrodeposition
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-27
    Huizi Shen, Hoe Chul Kim, Minjae Sung, Taeho Lim, Jae Jeong Kim

    Organic additives play an important role in regulating film growth and properties in Cu electrodeposition. 3‑Mercapto‑1‑propane sulfonate (MPS) and its dimer bis(3‑sulfopropyl) disulfide (SPS) are representative accelerators that promote Cu electrodeposition rate. In this study, the formal reduction potential of SPS to MPS was determined by measuring the equilibrium constants of thiol–disulfide interchange reactions with the reference thiol/disulfide pairs by 1H nuclear magnetic resonance (1H NMR) spectroscopy. The calculated formal reduction potential of SPS to MPS was 0.153 V (vs. standard hydrogen electrode). Based on this calculation, the cell potentials of Cu(I)(thiolate) formation reaction with either SPS or MPS, which is a key reaction in accelerating mechanism, were also estimated by ultraviolet–visible absorption and 1H NMR spectroscopies: they were found to be 0.202 V and 0.214 V for SPS and MPS, respectively. The positive cell potential indicates that the formation of Cu(I)(thiolate) complexes is thermodynamically favorable in the presence of additives.

    更新日期:2018-03-27
  • Redox commuting properties of polyaniline in hydrochloric, sulphuric and perchloric acid solutions
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-27
    Juliana Scotto, M. Inés Florit, Dionisio Posadas

    In the present work we have studied the pH dependence of the voltammetric response of polyaniline (Pani) in three different electrolytic media: HCl, H2SO4 and HClO4 at constant ionic strength. The electrochemical stability of Pani as a function of the pH is different for the three electrolytes. As the pH increases, the stability limit decreases in the order HCl > HClO4 > H2SO4. The voltammetric data were analyzed based on a theoretical expression for the redox potential as a function of the oxidation degree of the polymer. This analysis allows obtaining the acid dissociation constant for the three electrolytes, and an interaction parameter that reflects the change in the interaction energy between the redox centres of the polymer as the pH is increased. Particularly interesting is the HCl system, in which the pH can be increased up to about 5.0 without loss of the electrochemical activity. A further proof that the current vs. potential response may be represented by a reversible confined redox couple with interactions comes from the pH dependence of the peak current for the three electrolytes. As expected, the acid dissociation constants of the reduced and oxidized polymer do not depend much on the nature of the anions studied here.

    更新日期:2018-03-27
  • Monitoring of glucose and ethanol during wine fermentation by bienzymatic biosensor
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-27
    Anchalee Samphao, Preeyanut Butmee, Pranom Saejueng, Charida Pukahuta, Ľubomír Švorc, Kurt Kalcher
    更新日期:2018-03-27
  • Further investigation of the equivalence of staircase and linear sweep voltammograms. IV - Averaged-current staircase voltammetry applied to electrochemical reactions involving soluble species
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-27
    C. Montella

    This article focuses on the sampled-current and averaged-current staircase voltammetry techniques compared to linear potential sweep/cyclic voltammetry for the investigation of electrochemical reactions involving soluble species. First, based on analytical solutions of the relevant voltammetric models, theoretical investigation is carried out assuming reversible electron transfer reactions and different mass transport conditions in the electrolyte, i.e. semi-infinite or finite-length planar diffusion, and diffusion to an inlaid disk electrode. Next, solving numerically the appropriate integral-equation-based model, further investigation takes into account the electron transfer kinetics, the uncompensated resistance of the electrolyte, and the interfacial double-layer charging, under one-dimensional mass transport conditions. Main conclusion is that the averaged-current staircase voltammetry technique should provide nearly the same current data as the linear potential sweep/cyclic voltammetry technique under a variety of experimental conditions.

    更新日期:2018-03-27
  • 更新日期:2018-03-27
  • Synthesis of MXene/DNA/Pd/Pt nanocomposite for sensitive detection of dopamine
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-27
    Jiushang Zheng, Bin Wang, Ailing Ding, Bo Weng, Jiucun Chen
    更新日期:2018-03-27
  • A novel way for analysis of calycosin via polyaniline functionalized graphene quantum dots fabricated electrochemical sensor
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-24
    Jinying Cai, Bolu Sun, Xiaodan Gou, Yuqiang Gou, Wen Li, Fangdi Hu

    In this study, polyaniline functionalized graphene quantum dots composite with excellent performance was successfully prepared by situ polymerized, and it was applied to fabricate electrochemical sensor for analysis of calycosin in the complex samples of traditional Chinese medicine. The polyaniline functionalized graphene quantum dots composite was characterized by Fourier transform infrared spectroscopy and Raman analysis, to indicate that polyaniline functionalized graphene quantum dots composite was successfully synthesized. The morphology and microstructure of the modified electrodes were characterized by Scanning electron microscope and Transmission electron microscope. According to the results of cyclic voltammetry and electrochemical impedance spectroscope, the glassy carbon electrode modified with polyaniline functionalized graphene quantum dots composite significantly increased the electron transfer rate on the surface of sensor. Under the optimized conditions, the fabricated sensor was used for the analysis of calycosin in Radix Hedysari and Radix Astragali by differential pulse voltammetry, which displayed acceptable reproducibility, long-term stability, good selectivity and sensitivity. The proposed sensor exhibited a wide detection range (1.1 × 10−5–3.52 × 10−4 mol/L) with a detection limit of 9.8 × 10−6 mol/L (S/N = 3). This study provided a novel and convenient method for rapid evaluation of the quality of Radix Hedysari and Radix Astragali.

    更新日期:2018-03-24
  • One step growth of electro-assisted BSA functionalized screen-printed carbon interface with improved antifouling characteristics
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-24
    Mian Hasnain Nawaz, Gaelle Catanante, Jean Louis Marty, Akhtar Hayat
    更新日期:2018-03-24
  • Phenylamide-oxime and phenylamide nanolayer covalently grafted carbon via electroreduction of the corresponding diazonium salts for detection of nickel ions
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-22
    David Pally, Valérie Bertagna, Benoît Cagnon, Moslem Alaaeddine, Roland Benoit, Fetah I. Podvorica, Christine Vautrin-Ul

    This study focuses on the covalent grafting of thin organic layers on a glassy carbon electrode by aryl diazonium salts containing functional groups capable of complexing Ni(II) ions. The goal was to develop a modified electrode for the detection of Ni(II) ions in aqueous media. The glassy carbon electrode (GCE) surface was modified by electrochemical reduction of diazonium salts synthesized in-situ in aqueous acid medium from 4-amino-benzamide (4-AB) and 4-amino-benzamide-oxime (4-ABO). XPS, AFM, ellipsometry and cyclic voltammetry were used for surface characterization of the grafted GCE. The barrier properties of the grafted layer were determined and compared by cyclic voltammetry, using Fe(CN)63−/4−, Ru(NH3)63+/2+ and dopamine redox probes in different pH media. The adsorptive properties of the grafted glassy carbon were compared for Pb(II), Cu(II) and Ni(II) cations. The ability of these modified GCE to detect Ni(II) ions was then explored using a two-step method: i) complexation of Ni(II) by the grafted layer, followed by ii) electroreduction of the complexed Ni(II) and then its analysis by anodic square wave voltammetry. The 4-ABO grafted glassy carbon electrodes were able to detect Ni(II) in micro-molar concentration. The presence of ions such as Pb2+, Mg2+, Ca2+, K+ and Na+ did not interfere with the Ni(II) quantification. The phenyl-oxime functionalized electrodes showed good robustness during more than fifty electroanalysis.

    更新日期:2018-03-23
  • Nano-perovskite decorated carbon nanotubes composite for ultrasensitive determination of a cardio-stimulator drug
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-22
    Ekram H. El-Ads, Nada F. Atta, Ahmed Galal, Asmaa R.M. El-Gohary

    In this work, a new electrochemical sensor was fabricated based on Sr2PdO3 nano-perovskite manually mixed with carbon nanotubes (CNTs) and casted on glassy carbon (GC) electrode surface; GC/(CNTs-Sr2PdO3). Enhanced sensitivity, selectivity, stability and electron transfer kinetics were realized by the application of nano-perovskite modified carbon nanotubes composite for determination of dobutamine (DB). The proposed sensor showed high electro-catalytic activity in the linear dynamic range of 0.03 μmol L−1 to 50 μmol L−1 with sensitivity of 20.91 μA/μmol L−1, detection limit of 0.012 nmol L−1 and a quantification limit of 0.04 nmol L−1. The proposed method was successfully applied for DB detection in blood serum samples with good recovery results. The sensor showed anti-interfering ability in presence of common interferences as ascorbic acid, uric acid, acetaminophen, serotonin and morphine.

    更新日期:2018-03-23
  • Effect of polyphenol-polyamine treated polyethylene separator on the ionic conduction and interface properties for lithium-metal anode batteries
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-22
    You-Zhi Song, Jia-Jia Yuan, Xue Yin, Yin Zhang, Chun-Er Lin, Chuang-chao Sun, Li-Feng Fang, Baoku Zhu, Li-Ping Zhu
    更新日期:2018-03-23
  • An electrochemical investigation of the electrodeposition of non-intact tri-nuclear clusters on platinum working electrodes
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-22
    Edward Kennedy, Vladimir Katovic, Suzanne Lunsford

    The goal of this research was to study the electrochemical behavior of tri-nuclear clusters of molybdenum and tungsten - first in the ionic liquid EMIBF4, and then in the polar-aprotic solvent DMSO. Four tri-nuclear cluster compounds were studied: Hexa-μ2-acetatotriaquadi-μ3-oxotrimolybdenum (IV, IV, IV) trifluoromethanesulfonate [Mo₃O₂(O₂CCH₃)₆(H₂O)₃](CF₃SO₃)₂, Hexa-μ2-acetatotriaquadi-μ3-oxodimolybdenum (IV, IV) tungsten (IV) trifluoromethanesulfonate [Mo₂WO₂(O₂CCH₃)₆(H₂O)₃](CF₃SO₃)₂, Hexa-μ2-acetatotriaquadi-μ3-oxomolybdenum (IV) ditungsten (IV, IV) trifluoromethanesulfonate [MoW₂O₂(O₂CCH₃)₆(H₂O)₃](CF₃SO₃)₂, and Hexa-μ2-acetatotriaquadi-μ3-oxotritungsten (IV, IV, IV) trifluoromethanesulfonate [W₃O₂(O₂CCH₃)₆(H₂O)₃](CF₃SO₃)₂. All information gathered from CV data on tri-nuclear clusters will be discussed. The study of the electrodeposition efforts with molybdenum- and tungsten-based tri-nuclear clusters onto Pt electrodes in EMIBF4, and DMSO, will be compared to past investigations by Katovic et al. In addition, the electrochemical properties of these four trinuclear clusters in the DMSO-based solvent system were explored and are novel findings.

    更新日期:2018-03-22
  • Electrodeposition of gold on oxidized and reduced graphite surfaces and its influence on glucose oxidation
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-21
    R.A. Escalona-Villalpando, M.P. Gurrola, G. Trejo, M. Guerra-Balcázar, J. Ledesma-García, L.G. Arriaga
    更新日期:2018-03-22
  • Electrocatalytic properties of manganese and cobalt polyporphine films toward oxygen reduction reaction
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-21
    Dmitry V. Konev, Olga I. Istakova, Beata Dembinska, Magdalena Skunik-Nuckowska, Charles H. Devillers, Olivier Heintz, Pawel J. Kulesza, Mikhail A. Vorotyntsev

    Novel member of polymetalloporphines, namely manganese polymetalloporphine of type I (pMnP-I) obtained by ion exchange from magnesium polyporphine of type I (pMgP-I) is reported for the first time and compared to its cobalt analogue (pCoP-I). Both polymer films have been obtained via two-step procedure: demetalation of the pMgP-I electrode film via its exposure to trifluoroacetic acid solution, resulting in formation of the metal-free polyporphine of type I (pH2P-I) followed by electrochemically induced incorporation of Co or Mn ions from the acetonitrile solution of cobalt and manganese perchlorates. A further oxidative transformation of pCoP-I, pMnP-I polymer films has led to the corresponding polyporphines of type II, pCoP-II and pMnP-II, possessing such unique features as condensed polymer structure with a very high density of active sites and high electronic conductivity within a very broad potential range including the one corresponding to the neutral (uncharged) state of the polymer matrix. Both polymers of type II also exhibit interesting electrocatalytic activity toward oxygen electroreduction in aqueous neutral (pH 6.7) and alkaline (pH 13) media which was evaluated under cyclic voltammetric and steady-state conditions. The results demonstrate that the efficiency (regardless of the electrolyte) of both polymetalloporphines is comparable to bare platinum electrode. The effect of annealing of polymer-modified electrodes on their catalytic properties has also been considered.

    更新日期:2018-03-22
  • Simple and low price of monodispersed rice-like Fe2O3 supported by modified bamboo charcoal with enhanced lithium storage
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-21
    Congcong Zhang, Yonghang Xu, Wenyan Chen, Luyi Sun, Donghui Xu, Yun Yan, Xiaoyuan Yu

    Bamboo charcoal (BC) shows similar structure and property to the onion fullerene carbon and carbon nanotubes with hierarchical porous, microporous tunnel structure and good electrical conductivity. By simple treatment, a carbon substrate material with good electrochemical properties can be obtained. Monodispersed rice-like Fe2O3 supported by modified bamboo charcoal (MBC) are prepared via a facile precipitation of FeOOH anchored on carbon charcoal substrate combined with a high temperature calcination. The SEM results show that rice-like Fe2O3 uniformly anchored on hierarchical porous carbon-based microscopic structure with a size distribution between 80 and 100 nm. In addition, the hybrids exhibit good lithium storage property as anode materials. MBC shows stable cycle performance and the reversible capacity can still be maintained at 327 mAh g−1 after 150 cycles under 200 mA g−1. When incorporated with rice-like Fe2O3, the composite delivered a specific capacity of 1094 mAh g−1 after150 cycles at 200 mA g−1 and a high capacity of 765 mAh g−1 even at 1600 mA g−1.

    更新日期:2018-03-22
  • Electrochemical measurement of antibody-antigen recognition biophysics: Thermodynamics and kinetics of human chorionic gonadotropin (hCG) binding to redox-tagged antibodies
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-21
    Lee I. Partington, Stephen L. Atkin, Eric S. Kilpatrick, Samuel H. Morris, Mark Piper, Nathan S. Lawrence, Jay D. Wadhawan
    更新日期:2018-03-22
  • A protease-free and signal-on electrochemical biosensor for ultrasensitive detection of lead ion based on GR-5 DNAzyme and catalytic hairpin assembly
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-21
    Xinyi Huang, Junlong Li, Qiongyuan Zhang, Shuai Chen, Wei Xu, Jiayi Wu, Wuceng Niu, Jianjiang Xue, Chaorui Li

    A simple protease-free and signal-on electrochemical biosensor based on GR-5 DNAzyme and catalytic hairpin assembly (CHA) for sensitive lead ion (Pb2+) assay was constructed in this work. In the presence of Pb2+, GR-5 DNAzyme specifically reacted with Pb2+ and cleaved the substrate strand into two free DNA fragments, and one of the two fragments then opened the hairpin capture DNA (Hc) that was assembled on the Au electrode surface and triggered the CHA reaction. Exploiting the CHA strategy, a large number of the hairpin signal DNA (Hs) labeled with two methylene blues (Mbs) were captured on the Au electrode surface and generated an efficient electron transfer, resulting in the dramatic increase of methylene blue current. In this method, Pb2+ could be detected quantitatively in the range of 4 × 10−11–3 × 10−6 M, and the detection limit was as low as 2.7 × 10−11 M (S/N = 3). Experimental results demonstrated that the biosensor was highly specific for Pb2+ and exhibited remarkable improvements of electrochemical analytical performance. This biosensor was also used for the analysis of Pb2+ in the serum sample spiked with Pb2+, and the obtained result in good agreement with the correct values. The excellent performance of the biosensor shows its promising potential for the clinical diagnosis of lead poisoning.

    更新日期:2018-03-22
  • Electrochemical detection of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone using a cytochrome P450 2E1 decorated biosensor
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-21
    Hongli Zhao, Haiyan He, Libo Shi, Xuan Cai, Hong Li, Minbo Lan, Qian Zhang

    In this work, a novel electrochemical biosensor for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) was developed based on cytochrome P450 2E1 (CYP2E1). The biosensor was fabricated by immobilization of CYP2E1 with poly (diallyldimethylammonium chloride) (PDDA) - poly (sodium-p-styrenesulfonate) (PSS) electrolyte film on a screen-printed carbon electrode (SPCE) electrodeposited with gold nanoparticles (AuNPs). The procedures of electrode modification were characterized by using scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). With the good conductivity of AuNPs as well as the immobilized CYP2E1, the electrochemical performances of the proposed biosensor for the detection of NNK showed a wide linear range of 0–386 μM with a sensitivity of 79 μA cm−2 mM−1 and a low detection limit of 7.71 μM. Additionally, excellent selectivity and reproducibility were also obtained. The fabricated NNK electrochemical biosensor was successfully employed in urine sample determination, exhibiting great potential in the real sample analysis.

    更新日期:2018-03-22
  • Use of interelectrode material transfer of nickel and copper‑nickel alloy to carbon fibers to assemble miniature glucose sensors
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-21
    Jan Rozsypal, Daniel Riman, Vladimir Halouzka, Tomas Opletal, David Jirovsky, Mamas Prodromidis, Jan Hrbac
    更新日期:2018-03-22
  • High capacity surface route discharge at the potassium-O2 electrode
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-21
    Yuhui Chen, Zarko P. Jovanov, Xiangwen Gao, Jingyuan Liu, Conrad Holc, Lee R. Johnson, Peter G. Bruce

    Discharge by a surface route at the cathode of an aprotic metal-O2 battery typically results in surface passivation by the non-conducting oxide product. This leads to low capacity and early cell death. Here we investigate the cathode discharge reaction in the potassium-O2 battery and demonstrate that discharge by a surface route is not limited to growth of thin (<10 nm) metal oxide layers. Electrochemical analysis and in situ Raman confirmed that the product of the cathode reaction is a combination of KO2 and K2O2, depending on the applied potential. Use of the low donor number solvent, acetonitrile, allows us to directly probe the surface route. Rotating ring-disk electrode, electrochemical quartz crystal microbalance and scanning electron microscope characterisations clearly demonstrate the formation of a thick >1 μm product layer, far in excess of that possible in the related lithium-O2 battery. These results demonstrate a high-capacity surface route in a metal-O2 battery for the first time and the insights revealed here have significant implications for the design of the K-O2 battery.

    更新日期:2018-03-22
  • Electrochemical detection of hydroquinone based on MoS2/reduced graphene oxide nanocomposites
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-19
    Ying Peng, ZhaoRong Tang, YongPing Dong, Guang Che, ZhiFeng Xin

    Layered molybdenum disulfide/reduced graphene oxide (MoS2/RGO) nanocomposites were synthesized by solvothermal method, and were characterized by high-resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-rayphotoelectron spectroscopy (XPS), and Raman spectroscopy. The electrochemical properties of the nanocomposites were studied by cyclic voltammetry and electrochemical impedance spectroscopy. Hydroquinone was selected as model molecular to investigate the electrochemical responses of the modified electrode. The results found that the synergetic effect of nanomaterials endowed the nanocomposite excellent electrocatalytic behavior towards the electrochemical reaction of hydroquinone. Under the optimal condition, hydroquinone can be sensitively detected in the range of 1–9 nM with the detection limit of 0.3 nM (S/N = 3). The obtained results revealed MoS2/GRO composites exhibited superior electrochemical performance in the detection of hydroquinone, and it may have promising potential for electrochemical sensors.

    更新日期:2018-03-20
  • Hydrothermal preparation of CoO/Ti3C2 composite material for lithium-ion batteries with enhanced electrochemical performance
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-17
    Xuelin Li, Jianfeng Zhu, Yuan Fang, Wenjing Lv, Fen Wang, Yi Liu, Hui Liu

    The CoO/Ti3C2 composite is prepared via a facile hydrothermal route followed by calcination, of which the morphology and the microstructure are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). CoO nanoparticles with the diameter of 10–20 nm are uniformly coated on the surface of Ti3C2 nanosheets, which increases the surface areas and prevents the aggregation of CoO. In addition, the CoO/Ti3C2 composite as an anode material for lithium-ion batteries (LIBs) demonstrates a higher initial discharge capacity of 1389 mAh g−1 with a columbic efficiency of 61% at 100 mAh g−1. The reversible capacity can remain about 313 mAh g−1 after 100 cycles, which is much higher than that of the pure Ti3C2. The present results indicate that CoO/Ti3C2 composite has a potential application in the anode of LIB.

    更新日期:2018-03-18
  • Facile green synthesis of reduced graphene oxide/tin oxide composite for highly selective and ultra-sensitive detection of ascorbic acid
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-17
    Rinky Sha, Sushmee Badhulika

    In this work, we report a novel, cost effective and environmental-friendly green synthesis method of reduced graphene oxide (rGO) – tin oxide (SnO2) composite using lemon extract by hydrothermal process for selective and ultra-sensitive electrochemical detection of ascorbic acid. The electrochemical behavior of ascorbic acid at the surface of rGO-SnO2 composite modified glassy carbon electrode (GCE) was investigated by cyclic voltammetry (CV) technique whilst ascorbic acid sensing was performed by using differential pulse voltammetry (DPV) technique. An excellent sensitivity of 1200 μA mM−1 cm−2 (R2 = 0.990) towards ascorbic acid in the wide dynamic range of 400 μM −1600 μM without any surface fouling effect was observed which is, to the best of our knowledge, ~1.6 folds higher than previously reported ascorbic acid sensors. The as-fabricated sensor exhibited lower limit of detection (38.7 μM), superior reproducibility and selectivity towards interfering species such as glucose, urea, uric acid and Na+ ions. This enhanced sensing ability was studied and discussed in terms of forward biased nano-Schottky barriers at the rGO-SnO2 interface. The sensor was successfully evaluated for the detection of ascorbic acid in the vitamin C tablets and to predict unknown concentrations of ascorbic acid in PBS solution. This ultrasensitive, binder free rGO–SnO2 composite based sensor can be used for a simple, low cost and voltammetric detection of ascorbic acid in clinical diagnostics, pharmaceutical and food industries.

    更新日期:2018-03-17
  • Hopping mode SECM imaging of redox activity in ionic liquid with glass-coated inlaid platinum nanoelectrodes prepared using a heating coil puller
    J. Electroanal. Chem. (IF 3.012) Pub Date : 2018-03-17
    Justyna Jedraszko, Magdalena Michalak, Martin Jönsson-Niedziolka, Wojciech Nogala
    更新日期:2018-03-17
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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