Papers by Keyword: Electrocatalysis

Abstract: The anodic coating of α-PbO2-Co3O4-CeO2 on stainless steel was prepared by DC deposition in this paper. The effect of different conditions and solid particles on the binding, appearance and deposition rate of the composite was researched. The optimum conditions for electrode preparations were obtained as follows: the current density 1.5 A/dm2, electroplating time 2 h, temperature 40 °C, Co3O4 30 g/L and CeO2 15 g/L. On this condition, the α-PbO2-5.43wt% Co3O4-4.64wt%CeO2 composite coating can be obtained. SEM and linear sweep voltammeter were used for the analysis of the surface structure and oxygen evolution potential. The results showed that the doping particles can not only improve electrode surface area but also reduce the granularity of pellet. The α-PbO2-5.43wt%Co3O4-4.64wt%CeO2 electrode has a lower oxygen evolution potential and higher electrocatalytic activity than pure α-PbO2 electrode.

Abstract: Ag/graphene nanocomposites were prepared by the reduction of silver acetate (CH3COOAg)/graphene oxide with hydrazine gas. The samples were characterized by X-ray diffraction and scanning electron microscopy. The electrocatalytic activities of the synthesized samples for hydrazine and formaldehyde oxidation were also investigated by cyclic voltammetry. The results show that Ag/graphene nanocomposites can be prepared by this novel and simple process. The samples present high electrocatalytic activity for hydrazine and formaldehyde oxidation.

Abstract: A new ascorbic acid electrochemical sensor was made by electrostatic assembly of ferrocene polymer monolayer on the surface of gold electrode which modified with negatively charged alkanethiol. Cyclic voltammetry and current-time curve were employed to investigate the electrochemical characteristics of the sensor. The ferrocene monolayer modified electrode exhibit excellent electrocatalytic response to the oxidation of ascorbic acid. The anodic overpotential was reduced by about 180 mV compared with that obtained at a bare gold electrode in cyclic voltammetry. Under the optimal conditions, the linear range of the sensor response to ascorbic acid was from 0.05 to 1 mM and the detection limit was 2.710-5 M. The sensor possesses simple preparation, fast response and good electrochemical stability.

Abstract: By one-step co-electrodeposition Hemoglobin (Hb) and Au nanoparticles-chitosan (Au NPS-Chi) nanocomposite film on carbon ionic liquid electrode(CILE), the Hb immobilized with Au NPS-Chi nanocomposite film was stable and retained its functional activity. The results of cyclic voltammetrys showed a pair of well-defined and quasireversible redox peak of Hb with the formal potentials of −0.545V (vs.SCE) in 0.1 mol/L pH 7.0 PBS; a linearity range for determination of H2O2 is from 0.4 to 208.4μmol/L with a detection limit of 0.12 μmol/L (S/N=3). As a results, the one-step co-electrodeposition and the promising feature of nanocomposite could serve as a versatile platform for the fabrication of electrochemical biosensors.

Abstract: The PbO₂ film electrodes have been prepared by different electrodeposition process onto aluminum substrate.The electrochemical activity of the electrode for oxygen evolution reaction in 50g•L^-1Zn²⁺+150g•L^-1H₂SO₄ solutions have been studied. The results show that the best activity of the electrodes obtained A1/conductive coating was electrodepositing PbO₂ in alkaline lead solutions firstly, then plating PbO₂ in acidic lead nitrate solutions. This can be attributed to the conductivity of the substrate, the crystal phase structure and property of PbO₂. SEM-EDX analysis shows the beta-form, deposited from acidic solutions of Pb(II), has a distorted rutite structure, and the alpha-form, deposited from alkaline solutions, has the spherical cell. The high non- stoichiometry of PbO2 was obtained in alkaline lead solutions.

Abstract: Boron-doped diamond (BDD) electro- catalysis is one of the advanced oxidation processes (AOPs) can be widely applied in water treatment, because the unique physical and chemical properties enable BDD to be an ideal anode material in electrochemical oxidation of aqueous organic pollutants. In this work, electrocatalysis is conducted in research of treating isopropyl alcohol model wastewater and real wastewater of low molecular organics on BDD electrode. Experiments are performed both in static and dynamic mode with a batch reactor and a circulation cell, and the effect of current density is investigated. The results reveal the superiority of dynamic mode in treating model wastewater and real wastewater. And the optimum working currency density of dynamic electrocatalysis for model wastewater and real wastewater are 1.29mA/cm2 and 3.84mA/cm2, respectively.

Abstract: Homogeneous nano-CuS were synthesized by phase-transfer method, and the preparatory conditions were studied in detail. The synthesized nano-CuS was characterized by transmission electron microscopy (TEM) and UV–vis absorption spectroscopy. The results indicated that the as-prepared nano-CuS showed a willow-like structure with average diameter of 30-40 nm. Then a novel carbon paste electrode (CPE) based on these nano-CuS was prepared, and its chemical characteristics were researched. The modified CPE based on nano-CuS was used to detect of H₂O₂, and a satisfactory result was achieved.

Abstract: Ni-P alloy electrode was prepared by electroless plating on the Cu-Zn substrate. The surface morphology and textural properties of electrode were characterized by Scanning electron microscope(SEM), Energy dispersive spectroscopy(EDS) and X-ray diffraction(XRD). The performance of Ni-P alloy electrode was tested by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy.The results of cyclic voltammetry showed that: At room temperature, Ni-P alloy electrode had significant catalytic effect on the electrocatalytic oxidation of ethanol in alkaline solution. Results of chronoamperometry and electrochemical impedance spectroscopy further confirmed the catalytic effect of Ni-P alloy electrode on the electrochemical oxidation of ethanol.

Abstract: During electrodepositing pure lead dioxide, the electrocatalytic activity of PbO₂ electrodes, as well as their stability, can often be considerably enhanced by the incorporation of some fine particles added to the electrodeposition. The morphology, crystal phase, surface composition, microstructure, of the electrode were characterized by means of SEM, XRD and EDS. SEM-EDS analysis showed the addition of solid particles could inhibit the growth of α-PbO₂ unit cells, improving the specific surface areas of coating surface.Under all condition, the matrix was highly oriented α-PbO₂. The electrocatalytic activity of the prepared materials has been tested in Zn2+ 50g L-1, H2SO4 150g L-1 solution. It showed that the electrocatalytic activity of the A1/conductive coating/α-PbO₂-3.71 wt.% TiO₂-2.12 wt.% CeO₂ anode is the best.

Abstract: In this paper, we have successfully synthesized polyaniline nanotubes by using chemical oxidation polymerization. This synthesis is simple and an effective way to prepare one-dimensional polymer nanotubes. By transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectrum (FTIR), the morphology and physical structures of the as-prepared products were characterized. By cyclic voltammetry we studied the electrocatalytic activity of polyaniline nanotube modified glassy carbon electrode on ascorbic acid. The results show that the polyaniline nanotube modified electrode has excellent electrocatalytic activity on ascorbic acid. Compared with those of the bare glassy carbon electrode, the anodic peak potential of ascorbic acid shifts negatively 0.212 V on the modified electrode, and the anodic peak current increases 43 %. And the concentration of ascorbic acid shows a good linear relation at the range of 1.0×10^-5 ~ 0.1 M with the minimum detection limit of 1.0 × 10^-6 M.