A novel nickel oxide nanoparticles modified glassy carbon electrode was fabricated and used as a non enzymatic sensor for glucose determination. Aimed as promising alternative to conventional chemical methods, NiO-NPs were synthesized via a green synthetic approach using Nigella sativa Extract. NiO NPs were characterized using Fourier transfer infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy with EDS profile. Electrochemical measurements were performed using cyclic voltammetry (CV) and Chrono-ammperometry (CA) in 0.1 M NaOH solutions, revealing a well defined redox couple of Ni-III/Ni-II. The electrogenerated NiIII species on the electrode surface act as an excellent catalyst toward the glucose oxidation reaction. Our modified electrode presents good stability, short response time < 3 s, low detection limit around 3.2 mu M, and two linear ranges of detection from 50 mu M to 600 mu M, and from 1 mM to 10 mM with sensitivity equal to 987.85 mA cm(-2)mM(-1) and 170.85 mA cm(-2)mM(-1) respectively.

The effects of different parameters on the electric output of air-cathode microbial fuel cells were investigated in this work. The single microbial fuel cell was equipped by modifying Proton Exchange Membranes (PEM). Two membrane types were prepared: first by using the combination of Poly Vinyl Alcohol (PVA) with Polystyrene Sulfonate (PSSNa), while the second membrane was elaborated by mixing Poly Vinyl Chloride (PVC) with Methyl Tri-Octyl Ammonium (MTOA) chloride. The PEMs were incorporated into the air-cathode to form a Membrane Electrode Assembly (MEA) to promote electricity generation. PVA/PSSNa and PVC-MTOA membranes were synthesized by solution casting method. Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet (UV) Visible spectroscopy, Scanning Electronique Microscope (SEM), Differential Scanning Calorimetry (DSC), and water Contact Angle (CA) were used as characterization techniques to explore the membrane structure and properties. The performance and the electric capacity of the microbial fuel cell in real time were operated using an external resistance of 5kΩ. Impedance and resistance capacity were determined using the polarization method. It was found that the internal resistance of the PVA/PSSNa and PVC-MTOA membranes were 50 and 350Ω respectively. The voltage values at open circuit of the cells using PVA/PSSNa and PVC-MTOA membranes were 600mV and 150mV respectively. The values of power, current, and power density, are quite interesting. Cells with PVA/PSSNa and PVC-MTOA membranes gave values of 18.24 and 9.64mW.cm-2 respectively.

In this paper, we report on the electrochemical behavior of zinc (Zn) anode in Zn–MnO2 battery tested in aqueous NH4Cl electrolyte with a concentration ranging from 0.01 to 1 M without any additives. The Zn electrode shows the lowest corrosion behavior for the 0.1 M concentration. Such corrosion decrease was attributed to a shielding effect due to the formation of a corrosion layer expressed by a higher charge transfer resistance (Rct) of 270 Ω. The X-ray diffraction (XRD) analysis shows that it constitutes by ZnO, Zn(OH)2 and Zn(NH3)2Cl2. The Zn was successfully assembled with MnO2 to form a Zn/MnO2 cell using 0.1 M NH4Cl electrolyte. Two types of MnO2 powders were experimented as cathode namely nanostructured MnO2 (NMD) and commercial MnO2 (EMD). It was found that NMD gives the best performance in terms of output voltage and specific energy. Indeed, the Zn/NMD cell has a voltage of 1.743 V which is higher than that of Zn/EMD (1.674 V) at a current of 1 mA. It was found that the cells voltage decreased after 4 h of continuous discharge to 1.712 V and 1.660 V, respectively. Moreover, the Zn/NMD cell can reach a highest specific energy of 228.30 mWh/g. Therefore, our Zn/NMD cell can be used for a high-performance primary battery and take over Zn/MnO2 battery market.

A Nickel Schiff base complex, insoluble in water, was synthesized and used as modifier. A Nickel Schiff base modified carbon paste electrode MCPE was build. The electrodes were characterized by scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDXS), cyclic voltammetry and chronoamperometry. The modifier is elctroactive, a well defined redox couple of NiIII/NiII in alkaline medium was made in evidence. It presents a quasi-reversible system with electron transfer coefficient (0.38) and electron transfer rate of 4.5 s−1. The electrogenerated NiIII species on the surface of the electrode act as an excellent catalyst toward thiosulfate oxidation reaction with a chemical rate constant Kh equal to 23,6 M−1s−1. The different techniques involved in this study qualify our modified electrode as sensitive, reliable and very stable for thiosulfate analysis.

The electrochemical behavior of PbO2/PbSO4 electrode is investigated in 4.5 M H2SO4 in presence of three surfactants, Sodium Dodecyl Sulfate (SDS), Cetyltrimethylammonium bromide (CTAB) and Sodium tripolyphosphate (STPP), using cyclic voltametry, electrochemical spectroscopy impedance and galvanostatic discharge as techniques. The micro morphology of the surface of the modified PbO2 electrodes is examined by scanning electron microscopy. The results show that SDS and CTAB when added in the electrolyte could refine the coating particles and change the roughness of the surface of the electrode leading to a thin film of PbO2 with amorphous character. In addition, SDS and CTAB shift the hydrogen evolution potential towards more negative values, improve the discharge capacity of the anodic layer and accelerate the charge transfer. Under cathodic polarization, CTAB presents the lowest value of the charge transfer resistance Rct. In the contrary, STPP shifts the oxygen evolution potential towards more positive values, passivates the surface of the electrode and inhibits completely the reaction of PbO2 formation.

In this work, manganese metal and its nanostructured dioxide (MnO2) were applied as electrodes for the development of a new Mn/MnO2 battery. The MnO2 was deposited onto platinum substrate using electrode-position technique and collected as powder cathode in the new battery. The influences of temperature and precursor pH on the MnO2 film properties were investigated. Scanning electron microscopy, X-ray diffraction (XRD), energy dispersive X-ray analysis and transmission electron microscopy (TEM) were used to characterize the MnO2 deposit. The XRD and TEM demonstrate that the MnO2 was deposited in its gamma-MnO2 phase with a particle size less than 15 nm. In addition, the pH solution plays a key role in the electrochemical performance of the MnO2 as a cathode. Indeed, the gamma-MnO2 deposited at pH = 2 provides a high discharge performance in KOH and NH4Cl aqueous electrolytes. This led to a new Mn/MnO2 cell with better performance compared to the classical Zn/MnO2 cell in terms of discharge in NH4Cl electrolyte. During the discharge process, co-insertion of Mn2+ and H+ promotes the transformation of MnO2 into MnxMnO4, MnOOH, and Mn2O3. In addition, the Mn/MnO2 cells exhibits a high output voltage >2 V in NH4Cl. It reach a high voltage at around 1.89 V after 3 h of continuous discharge. The cells can achieve a discharge capacity of 1000 mA h.g(-1) at a current density of 330 mA g(-1) with the highest specific energy of 1890 mWh.g(-1). Moreover, Mn/MnO2 cells are more stable in NH4Cl electrolyte which exhibits a voltage drop of 6% after 3 h of continuous discharge. Such results demonstrate that the assembled Mn/MnO2 battery can occupy an important place in the energy storage field as a low cost and high performance device

Lead dioxide was prepared by chemical and electrochemical routes. The chemical samples were obtained by dissolving lead tetra-acetate in distilled water at room temperature. The electrochemical samples were obtained by oxidizing cured plates in sulfuric acid containing different concentrations of surfactant. The discharge of the different samples in sulfuric acid showed that the capacity of the chemical electrodes is independent of the crystallite size. In contrast the capacity of the electrochemical powders decreases with the increase of the crystallite size. Thermal analyses of the different samples were investigated to show the difference between the two methods.

A solid polymer electrolyte with a polyvinyl alcohol (PVA) matrix and a mixture of ethylene glycol (EG) and phosphoric acid as proton conductor has been developed. These complexes have been studied by X-ray diffraction (XRD), infrared Fourier transform spectrometry (FTIR) and electrochemical impedance spectrometry (EIS). The optimum ionic conductivity value of the ternary PVA-EG(45 wt%)-H3PO4(5 wt%) complex film has been achieved to be 5.2 10(-3)S cm(-1) at RH = 100% with adequate mechanical properties (especially flexibility) and with a low activation energy of 9 kJ mol(-1). Due to its good electrical and mechanical properties, this material has been successfully used as solid state proton electrolyte in Zn/MnO2 cell delivering a capacity of 220 Ah kg(-1) and an energy density of up to 286 Wh kg(-1).

Intermediate oxides are synthesized by heating fresh lead dioxide obtained from commercial positive plates of lead-acid batteries. These oxides are soaked in sulfuric acid with 1.28 s g under stirring for 1 h. The obtained powders are analyzed using X-ray diffraction and chemical analysis. The samples are discharged with a cathodic current of 1 mA in sulfuric acid with 1.28 s g, and the capacity is determined. It is found that lead dioxide obtained from PbO1.55 is more active than the fresh sample. It shows an increase in capacity of 17%. This is due to the increase in the quantity of structural water as given by the chemical and thermal analyses.

In this work, we report the results of the electrodeposition of MnO2 film on stainless steel (SS) electrode in aqueous MnSO4 solution which was used as photocatalyst to degrade the Rhodamine B (RhB). Different techniques such as field emission gun scanning electron microscopy (FEG-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), Braunauer Emett and Teller (BET), and UV-visible diffuse reflectance spectroscopy (UV-vis DRS) were used to characterize the deposited MnO2 film. It was found that MnO2 is electrodeposited as a gamma-MnO2 nanoparticle film with a low rate of crystallinity and high specific surface area of about 140 m(2) g(-1). The particle size is less than 20 nm. In addition, the diffuse reflectance measurements show that the gamma-MnO2 presents a direct band gap of about 1.41 eV. The Mott-Schottky plot confirms that gamma-MnO2 is a n-type semiconductor with the flat band potential V (FB) = 0.016 V vs. Ag/AgCl and the electron concentration N (D) = 0.8 x 10(20) cm(-3). The conduction and valence energy band values were estimated at Ec = 4.498 eV and Ev = 5.908 eV, respectively. It was shown also that these films exhibit good ability for the degradation of RhB especially under visible light irradiation. Indeed, degradation rates of about 90 and 55% were obtained after 60 min of visible and UV light irradiation, respectively. Finally, the degradation process mechanism of RhB is discussed.

β-Lead dioxide is prepared by chemical and electrochemical routes. The chemical sample is obtained by dissolving lead tetra-acetate in distilled water at room temperature. The electrochemical sample is prepared by oxidizing cured plates in sulfuric acid with 1.05 g cm−3 specific gravity. The two powders are indexed as β-PbO2. The sample prepared by chemical route presents smaller crystallite size. When cycling the two powders up to 100 cycles between 0.5 and 1.5 V versus Hg/Hg2SO4 reference electrode, the electrochemical sample presents higher values of anodic and cathodic peak current densities and higher discharge capacity. Thermal analysis and electrochemical techniques are used to explain this difference in activity between the two samples.

Pb, Pb-Sb and Pb-Sb-Se alloys were investigated in 4.5 M H2SO4 in presence of SDS, C19 and STPP as surfactants using cyclic voltammetry and electrochemical spectroscopy impedance as techniques. The three additives show a positive effect when pure Pb is considered. Similar voltammograms to that of the blank test are obtained on Pb-Sb alloys. C19 seems to improve the discharge capacity of the anodic layer whereas STPP inhibits almost completely the oxidation of the substrate. Under cathodic polarization, C19 presents the lowest value of the charge transfer resistance R-ct,

Nickel(II)-DHS complex was obtained from N,N′-bis(2,5-dihydroxybenzylidene)-1,2-diaminoethane (H2DHS) ligand and nickel acetate tetrahydrated in ethanolic solution with stirring under reflux. This complex, dissolved in an alkaline solution, was oxidized to form electroactive films strongly adhered on the ITO (indium tin oxide) electrode surface. In this alkaline solution, the poly-[NiII-DHS]/ITO films showed the typical voltammetric response of (Ni2+/Ni3+) redox couple centers which are immobilized in the polymer-film. The modified electrodes (MEs) obtained were also characterized by several techniques such as scanning electronic microscopy, atomic force microscopy and electrochemical methods. The electrocatalytic behavior of these MEs toward the oxidation reaction of some aliphatic alcohols such as methanol, ethanol, 2-Methyl-1-propanol and isopropanol was investigated. The voltammograms recorded with these alcohols showed good electrocatalytic efficiency. The electrocatalytic currents were at least 80 times higher than those obtained for the oxidation of methanol on electrodes modified with nickel hydroxide films in alkaline solutions. We noticed that these electrocatalytic currents are proportional to the concentration of methanol (0.050–0.30μM). In contrast, those recorded for the oxidation of other aliphatic short chain alcohols such as ethanol, 2-methyl-1-propanol and isopropanol are rather moderately weaker. In all cases the electrocatalytic currents presented a linear dependence with the concentration of alcohol. These modified electrodes could be applied as alcohol sensors.

The organo-acid-activated bentonite (OAB) was prepared and characterized by SEM, XRD, FTIR, pH(PZC) and BET. Then the OAB was employed as adsorbent for the removal of bisphenol A (BPA) and 2,4,5-trichlorophenol (TCP) from aqueous solutions. The adsorption performances of OAB were investigated by batch mode experiments with respect to pH, temperature, initial concentration, contact time and competitive adsorption. The Langmuir model describes better the results of BPA adsorption while the results of TCP are best fitted to Freundlich model. The maximum adsorption capacities are found to be 127.7 and 244.6 mg/g for BPA and TCP, respectively. The kinetic properties were well described by the pseudo-second-order equation. Thermodynamic parameters suggest that the adsorption process of BPA and TCP onto organoclay (OAB) are physisorption, spontaneous and exothermic. In binary solutions, BPA and TCP show competitive adsorption. Hydrophobic interaction play an important role during the sorption process. In addition, OAB could be regenerated and reused for adsorption of BPA/TCP again.

To obtain new materials, we modified Algerian halloysite by thermal activation (HalC), acid activation (HalA), combined thermal-acid activation (HalCA) and acid-thermal activation. X-ray diffraction, Fourier Transform infrared and BET textural analysis were used to characterize changes. After the HalC of halloysite at 600 degrees C, no XRD peaks were shown and a total disappearance of the absorption bandsranging from 3,700 to 3,600cm(-1). The treatment of halloysite by sulphuric acid increases the surface area from 185.4 to 321.0m(2)/g. Halloysite is first calcined and then activated by acid, its surface area increases from 74.3 to 538.6m(2)/g. The effect of initial pH, adsorbent dose, contact time and temperature on the removal of 2,4,5-trichlorophenol (TCP) by modified halloysite samples was investigated. Equilibrium data were fitted to the Langmuir, Freundlich and Toth models. The best fit of the cited models was the Freundlich model, which suggested infinite adsorption onto heterogeneous surface. The pseudo-first-order, pseudo-second-order and intraparticle diffusion models were applied to the experimental kinetic data. The results showed that the pseudo-second-order is the best model to describe the process. The study of thermodynamic parameters shows that the process of adsorption of TCP onto the prepared samples was spontaneous, endothermic and physical in nature.

This study attempts to discuss the influence of Bi alone and its combination with Sb and Sn on the electrochemical performance of the PAM of lead acid batteries. The different additives were added in the electrolyte as cations. PAMs were prepared by electro formation of cured battery plates in the presence and absence of a dopant (non-doped sample ND). The results from different analyses showed that bismuth alone gives a remarkable improvement of the capacity. The highest performance of PAM is obtained when bismuth is mixed with tin together as dopants. The incorporation of bismuth and tin cations leads to an increase of the quantity of structural water in PAM. This increases the hydrated and amorphous zones within the PbO2 particles and leads to an improvement of the electrochemical capacity.

The nanostructured MnO2 powder was successfully synthesized by electrodeposition on stainless steel (SS) substrate from hot 0.3 M MnSO4·H2O aqueous solution with pH value adjusted to 2. The electrochemical behavior of synthesized MnO2 was compared to that of the commercial electrolytic manganese dioxide (EMD). The investigation was conducted using a new cell which is manufactured in our laboratory. This gave us the possibility to present a new contribution and an improvement in the study of MnO2 electrochemical behavior. The analysis of the synthesized MnO2 and EMD powders by different techniques: FEG-SEM, EDS, TEM, XRD, and BET revealed the presence of electrodeposited nanostructured γ-MnO2 with high specific surface area of 139.59 m2 g−1 for the nanostructured MnO2 and 46.60 m2 g−1 for EMD. The electrochemical study of these powders conducted by linear voltammetry, electrochemical impedance spectroscopy (EIS) measurements, and Zn/MnO2 battery tests in 0.1 M NH4Cl electrolyte showed that the performance of the synthesized nanostructured MnO2 powder was higher than that of the commercial EMD powder.

The objective of this work is to improve the performance of the positive electrode of lead-acid battery. The use of the additive in the positive paste is to increase the capacity and cycle life of the positive active material. Mineral porous additives, dispersed uniformly in the PAM, may act as acid reservoirs and favor the ionic diffusion. The results show that the addition of mineral additive in the paste before oxidation influences the composition and the crystal size of the PAM after oxidation. We observe a remarkable improvement of the discharge capacity of the PAM for an amount of additive ranging between 1 and 5%. Nano-sized particles of PbO2 with amorphous character are obtained. XRD, TG and DSC, SEM, and galvanostatic discharge were used as techniques of investigation.

We prepared MnO2 by electrolysis of manganese sulfate solution recovered from used batteries and commercial manganese sulfate solution. The comparative study of the two samples using electrochemical techniques in alkaline solution shows that the two samples exhibit the same behavior. From XRD, we identified and indexed both samples by γMnO2 orthorhombic structure. We estimated the proton diffusion coefficient using galvanostatic intermittent titration technique (GITT). Our calculated data are in good agreement with theoretical values for both samples. In addition TG analysis shows the same thermal profile for both samples.

A new SOFC cathode material, La1.98NiO4±δ, was tested in presence of two electrolytes, yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC). XRD analysis showed the absence of undesirable phases at the La1.98NiO4±δ/GDC interface, whereas lanthanum zirconate (La2Zr2O7), an insulating phase, is present between electrode La1.98NiO4±δ and YSZ electrolyte. XPS analysis showed that the oxygen lattice can be present in form of LaO and LaNiO3, which explains the high conductivity for these materials. At temperatures lower than 650°C, the area specific resistance of the electrodes, measured by electrochemical impedance spectroscopy is significantly inferior when associated to GDC rather than YSZ electrolyte. In addition, in the case of GDC, a lower activation energy of about 0.7eV was obtained, which could be explained by a higher mobility of oxide ions at the La1.98NiO4±δ/GDC interface compared to the La1.98NiO4±δ/YSZ one.