Lead Dioxide Electrode Research Articles

Influence of duty cycle on the structure and electrocatalytic properties of pulse electrodeposited lead dioxide electrodes

In this work, PbO2 electrodes were prepared by pulse electrodeposition in the lead nitrate plating bath. Effects of duty cycle on the morphology and phase structure were investigated by scanning electronic microscopy (SEM) and X-ray diffraction (XRD), respectively. The SEM and XRD results show that the decrease of duty cycles decreases the grain size of PbO2 electrodes. The steady-state polarization curves and accelerated life tests demonstrate that the oxygen evolution overpotential and service life of PbO2 electrodes increase with the decrease of duty cycle, the PbO2 electrodes prepared at 20 % duty cycle possess highest oxygen evolution overpotential and service life, and the service life of PbO2 electrodes prepared at 20 % duty cycle reaches 71 h which is almost two times longer than that of the PbO2 electrodes prepared by direct electrodeposition. The bulk electrolysis shows that the methyl orange (MO) degradation on the PbO2 electrodes prepared by pulse electrodeposition is the pseudo-first-order reaction and the chemical oxygen demand and MO removal on PbO2 electrodes increase with the decrease of duty cycle, which can be attributed to the higher oxygen evolution overpotentials and electrochemical active surface area of PbO2 electrodes.

Novel phosphorus-doped lead oxide electrode for oxygen evolution reaction

A facile and cost-effective electrochemical approach was proposed for the first time to prepare a phosphorus-doped lead dioxide (P-PbO2) electrode on a lead substrate. This was achieved by introducing a pyrophosphate solution containing Cu2+, F− and peptone as essential additives. Such a novel P-PbO2 electrode exhibits a significantly improved electrocatalytic activity for the oxygen evolution reaction as compared to a traditional Pb/PbO2 electrode.

Preparation and Application of Lead Dioxide Electrode for Zinc Electrolysis

According to the process of anodic oxygen evolution in sulfate system for zinc electrolysis,Ti-base lead dioxide electrode can be prepared to use in this case.The surface characterization of the electrode was studied by Scanning electron microscopy(SEM) and X-ray diffraction(XRD).The electrode lifetime was tested in 1mol/L H2SO4solution at 60°C,and the electro-catalytic properties was examined by polarization curves.Then these samples was enlarged and simulation test was conducted at Mengzi marriage zinc smelter in Yunnan.The results show that the electro-catalytic properties is better and the electrodes lifetime is longer compared to the traditional lead electrode.Moreover,it has a significant effect in reducing energy consumption, manufacturing cost and improving the production and grade of zinc.

Electrodeposition of Ce-doped PbO2

An investigation is reported on lead dioxide electrodeposition from methanesulfonate electrolytes, that additionally containing Сe3+ ions. It is shown, that ion additive influences on kinetics of PbO2 formation without changing of process mechanism. During the deposition are formed lead dioxide electrodes micromodified by cerium that have different physico-chemical properties vs. traditional PbO2-anodes. Electrocatalytical reactivity of electrodes involved in respect to oxygen evolution was investigated.

Electrochemical fabrication and preliminary examination of modified lead dioxide bulk and analytical electrodes

The article describes the electrochemical fabrication of modified lead dioxide (PbO2) electrodes through a simple but efficient electrodeposition method. One of the goals was to assess the properties of the modified PbO2 as an electroanalytical electrode. A second objective was its use in bulk electrolysis against persistent organic pollutants in water. PbO2 was deposited galvanostatically at a current density of 10 mA cm−2 over the as-obtained and anodized Pd/Ag alloy substrate at 10 V. The electroanalytical studies of the modified PbO2 showed satisfactory electrochemical activity for ferrocene compared to that on commercial glassy carbon. The modified PbO2 electrode having an area of 4 cm2 was employed to eradicate phenol and 2-nitrophenol from water samples. 2-Nitrophenol was completely removed (99 %) and phenol (>50 %) was partially removed by bulk electrolysis at the optimized current density of 20 mA cm−2 for 3 h. Incomplete degradation in the latter case was due to the adsorption of electrochemically generated intermediates. The degradation monitoring was performed by cyclic voltammetry, UV–vis spectroscopy, and HPLC methods and the results were in good agreement with each other. The assays and morphological studies by SEM revealed the role of Nafion in the modified PbO2 electrode for efficient degradation of phenols through the bulk electrolysis.

Study on Preparation of Modified Ti-Based Lead Dioxide Electrode and Degraded Methylene Blue

A modified electrode was prepared by the electrodeposition of a lead oxide layer on a titanium substrate. Characterize the electrochemical performance of electrode by adopting CHI860D electrochemistry workstation while evaluating the electro-catalytic performance of electrode with Methylene Blue (MB for short) solution as target degradation product. The results show that the interlayer proportion of SnCl4:SbCl3 is 6:1 when the thermal decomposition temperature is 550°C, the electrode material prepared in plating solution with a concentration of 0.15mol/L has excellent electrocatalytic performance against MB, and the degradation rate could reach above 98%.

Potential Response of Lead Dioxide/Lead(II) Galvanostatic Cycling in Methanesulfonic Acid: A Morphologico-Kinetics Interpretation

In the light of electrochemical quartz crystal microbalance (EQCM), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and Potential vs. Time responses analysis, a new interpretation of the evolution of a lead dioxide (PbO2) electrode potential during PbO2(s)/Pb2+(aq) galvanostatic cycling in methanesulfonic acid is proposed. This interpretation relies on the morphological changes of the PbO2 surface highlighted by SEM images and the double layer capacitance evaluation. It is likely that these surface changes alter the specific surface area of the layer and therefore the local current density of the PbO2 deposition/dissolution reactions. In particular, it has been found that a high porosity is created during the first part of the second deposition step and in the subsequent deposition steps of cycling, which can explain the low polarization associated with these periods. This porosity most probably remains encapsulated in the layer when more PbO2 is deposited. It is then released during the following dissolution periods, which again affects the electrode potential by decreasing the polarization.

Typical Rare Earth Doped Lead Dioxide Electrode: Preparation and Application

Typical Rare Earth Doped Lead Dioxide Electrode: Preparation and Application

Effect of SnO2‐Sb2O5 Interlayer on Electrochemical Performances of a Ti‐Substrate Lead Dioxide Electrode

AbstractThe Ti/SnO2‐Sb2O5/PbO2 electrode was prepared by electrodeposition method onto Ti substrate with SnO2‐Sb2O5 interlayer. Microstructure information of SnO2‐Sb2O5 interlayer and PbO2 coating was characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). Our study shows that the titanium substrate is completely covered by the SnO2‐Sb2O5 solid solution interlayer and the interlayer combines the Ti substrate closely with the PbO2 coating. The electrochemical performance of the Ti/SnO2‐Sb2O5/PbO2 electrode was studied by cyclic voltammogram (CV), electrochemical impedance spectroscopy (EIS) and accelerated life test. The results show the electrochemical activity, electrical conductivity and stability of Ti‐substrate lead dioxide electrode are increased. The deactivation process of the Ti/SnO2‐Sb2O5/PbO2 electrode was also studied by the EIS. The SnO2‐Sb2O5 interlayer can effectively prevent the growth of a TiO2 insulating layer between the substrate and the PbO2 coating during the lifetime tests, thus maintain high activity of Ti/SnO2‐Sb2O5/PbO2 electrode for 10 times longer than Ti/PbO2 electrode without interlayer.

Influence of F‐ doping on the microstructure, surface morphology and electrochemical properties of the lead dioxide electrode

The lead dioxide electrode (PbO2) with Ti substrate and SnO2‐Sb2O5 intermediate layer was doped by F‐ ion through the potentiostatic anode co‐deposition method. The content of F in the coating can be controlled by adjusting deposition potential. The effect of F‐ doping on the composition, surface morphology and electrochemical properties of the PbO2 electrode was characterized by X‐ray diffraction, scanning electron microscope, X‐ray photoelectron spectroscopy and electrochemical measurement methods. The results have confirmed that the content of β‐PbO2 increases with increasing that of F, and the doping can make the β‐PbO2 grains become fine and the electrode surface become smooth; the specific surface areas and conductivity increase, and the initial potential of oxygen evolution shifts toward positive direction compared with the free‐doped PbO2 electrode; the oxygen evolution potential increases with the increasing of the F‐content in the PbO2 film electrode. The bulk electrolysis result demonstrated that the performances of the F‐PbO2 electrode for anodic oxidation aniline have been improved to some extent. Copyright © 2012 John Wiley & Sons, Ltd.

Kinetics of surface reactions on rotating disk electrodes

The diffusive–convective equation under the hydrodynamic conditions of rotating disk electrodes was solved for electrochemical reactions following the Langmuir–Hinshelwood kinetic mechanism, and an expression has been obtained for the current (reaction rate) as a function of the rotation rate, considering adsorption–desorption equilibrium and slow reaction of adsorbed species on the electrode surface. This expression has been applied to the experimental evaluation of electrochemical oxygen transfer to p-methoxyphenol and p-nitrophenol on lead dioxide electrodes. The Langmuir equilibrium constants and kinetic reaction rate constants obtained with the rotating disk electrode compare well with the corresponding values determined from independent adsorption isotherm and electrolysis studies, respectively, demonstrating that the approach presented appropriately describes the kinetic couplings between mass transport, adsorption–desorption equilibrium, and surface reactions, occurring in processes following the Langmuir–Hinshelwood mechanism.

Performance characterization of Ti substrate lead dioxide electrode with different solid solution interlayers

In this study, Ti substrate was coated by three different mixed oxides (SnO2–Sb2O5, RuO2–TiO2, IrO2–Ta2O5), then PbO2 was electrodeposited on them to prepare PbO2 electrode. The microstructure of the solid solution interlayers and PbO2 coatings was characterized by scanning electronic microscopy and X-ray diffraction. The results indicated that the above oxides interlayer exited in the form of solid solution and the interlayer covered the Ti substrate largely. Accelerated life test proved that the presence of solid solution interlayer can increase the stability of PbO2 electrodes in electrolysis. Cyclic voltammogram indicated that the PbO2 electrode with the solid solution interlayer have more active surface area in sulfuric acid solution. Linear scanning voltammograms showed that the over potentials of the oxygen evolution are decreased with the addition of the solid solution interlayer. Electrochemical impedance spectroscopy showed that the presence of interlayer can increase the electrochemical activity of oxygen evolution reaction and electrical conductivity.

Research on PEG modified Bi-doping lead dioxide electrode and mechanism

Bi-doping PbO2 electrode, which is called Bi–PbO2 for short, modified with different concentrations of polyethylene glycol (PEG) was prepared by electrodeposition method in this paper. The microstructure and electrochemical properties of the different modified electrodes were investigated using scanning electron microscopy, X-ray diffraction, Mott–Schottky, electrochemical impedance spectroscopy and linear sweep voltammetry techniques. The results show that adulteration of PEG has a noticeable improvement in the morphology of Bi–PbO2 electrode which can greatly decrease its particle size and enlarge its active surface area. Phenol degradation experiments reveal that the modified electrodes have excellent electro-catalytic activity and stability, and the optimal adulterate concentration of PEG is 8gL−1. Electrochemical performance tests show that the modified electrodes exhibit more negative flatband potential (Efb), larger adsorption pseudo capacitance, lower adsorption resistance and higher oxygen evolution potential, and these characteristics promote the electro-catalytic activity of the Bi–PbO2 electrode. Finally, accelerated lifetime tests demonstrate that PEG modification can highly lengthen the service life of Bi–PbO2 electrode in its practical application.

Electrochemical oxidation of 1,3,5-trimethoxybenzene in aqueous solutions at gold oxide and lead dioxide electrodes

A kinetic study of the electrochemical oxidation of 1,3,5-trimethoxybenzene (TMB) by direct electron transfer at treated gold disk was combined with results of electrolysis in order to produce total degradation into CO 2 and H 2O at Ta/PbO 2 anode. The oxidation of TMB at gold electrode was studied by cyclic voltammetry. The cyclic voltammogram shows one irreversible anodic peak (I) corresponding to the oxidation of adsorbed TMB molecules. The proposed mechanism is based on the hypothesis of two-electron oxidation of TMB molecule leading, via intermediate of a radical cation, to the formation of the 2,4,6-trimethoxyphenol (TMP) and an adsorbed polymeric film. The TMP molecule undergoes a rapid oxidation leading to the formation of 2,6-dimethoxy-p-benzoquinone (DMBQ) as a major product. Degradation of TMB was studied by galvanostatic electrolysis using Ta/PbO 2 anode. The influence of initial TMB concentration and applied current density was investigated. Measurement of total organic carbon (TOC) and analysis by HPLC were used to follow this degradation. The experimental data indicated that the removal of TMB follows a pseudo first-order kinetic. The efficiency of the electrochemical process increases at lower current density and higher TMB initial concentration while it decreases with the TOC removal progress.

Investigation on electrochemical properties of cerium doped lead dioxide anode and application for elimination of nitrophenol

The present work focused on the investigation of electrochemical properties of cerium doped lead dioxide anode, i.e. Ti/Ce–PbO 2. SEM, AFM, XRD and XPS were used to characterize the morphology, crystal structure and elemental states of the modified anode. Electrochemical impedance spectroscopy (EIS) was also utilized to study the electrochemical property of Ti/Ce–PbO 2. The electrochemical activity of the Ti/Ce–PbO 2 anode was investigated by means of bulk electrolysis and compared with that of a PbO 2 anode. The accelerated life test and oxidants determination were also conducted. The results indicated that the incorporation of cerium improved the electrocatalytic activity and stability of PbO 2 anode. The service life of Ti/Ce–PbO 2 electrode was much longer than that of traditional lead dioxide electrode. The electrochemical activity obtained from degradation of o-nitrophenol ( o-NP) outperformed the traditional lead dioxide electrode as well. The Ti/Ce–PbO 2 electrode is considered a promising anode for the treatment of organic pollutants.

Anodic oxidation of chlorpyrifos in aqueous solution at lead dioxide electrodes

The aim of this work is the use of electrochemical process for the total mineralization of water contaminated with organophosphorus pesticides like chlorpyrifos. This pesticide is widely used both for agricultural pest control and in households as a termiticide. The process was studied under galvanostatic polarization mode using Nb/PbO 2 anodes and graphite carbon bar as cathode. The kinetic of organic matter decay and the mineralization efficiency were evaluated by means of the chemical oxygen demand (COD) measurement. The influence of the experimental parameters such as the initial concentration of chlorpyrifos, the apparent current density and the temperature, on the electrochemical process performance was investigated. The experimental results showed that COD removal always follows a pseudo-second-order kinetics. The degradation rate increased significantly with increasing the apparent current density and temperature. However, it decreased with the increase of the initial pollutant concentrations. The best COD removal (76%) was obtained when using an apparent density of 50 mA cm −2, initial COD = 450 mg O 2 L −1 and at 70 °C in 10 h electrolysis time.

Preparation and Performance of Ti-based Lead Dioxide Electrode Modified with Polyethylene Glycol

PbO2 electrodes modified with different concentrations of polyethylene glycol (PEG) were prepared by electrodeposition. SEM and XRD were employed to investigate the surface morphology and crystal structure of PbO2 electrodes, and its electrocatalytic acitivity was analyzed through degradation experiments of phenol. Fur- thermore, electrochemical impedance spectroscope (EIS) and liner sweep voltammetry (VA) were carried out to get a better understanding of its electrochemical properties. SEM images and XRD patterns show that PEG can de- crease the partical size of PbO2 and improve the crystal purity of β-PbO2. The modified electrodes exhibite better electrocatalytic activity, lower charge transfer resistance and higher oxygen evolution potential compared with un- modified electrodes in the electrochemical experiments. Additionally, five times degradation experiments of phenol and accelerated lifetime tests reveal that the optimal electrode modified with 6g/L PEG has excellent electrocata-

Model Simulation and Analysis of Proton Incorporation into the Positive Active Mass of a Lead/Acid Battery

In this theoretical work, a mathematical model of the positive active mass of a lead/acid battery considering the effect of proton incorporation into the solid material of the lead dioxide electrode is presented. It can be regarded as an extension of a classic isothermal description, well known from literature. The influence of the proton incorporation reaction on the transient behavior as well as on the steady-state profiles has been analyzed and compared to the classical model. A significant influence of the process of proton incorporation on the transients of the model quantities was found, which reflects a pseudocapacitive behavior of the positive active material. This effect stabilizes the positive electrode potential, especially at a short-time high rate current flow. It could be shown that the transport of protons through the active mass is also present in steady-state conditions. This allows the protons two alternative ways of transportation, liquid and solid phases, in both transient and steady-state situations. Proton transport in the solid phase has not been considered before and may explain the high pseudocapacity of lead dioxide positive active material.

Influence of lead dioxide electrodes morphology on kinetics and current efficiency of oxygen-ozone evolution reactions

AbstractInfluence of electrode morphology on electrochemical properties of lead dioxide electrodes (β-PbO2) for oxygen-ozone evolution reactions in acid medium was investigated using scanning electronic microscopy (SEM), cyclic voltammetry (CV), polarization curves (PC), and determination of the current efficiency (Φ). Experimental findings revealed that application of high electrodeposition current densities furnishes more rough β-PbO2 films. Surface characteristics were verified by SEM images and the analysis of interfacial pseudo-capacitances and morphology factor (φ). Kinetic study of the overall electrode process (O2 + O3) based on the analysis of the Tafel slope revealed that the electrode morphology and electrolyte composition considerably affect the electrode kinetics. In most cases, the existence of two Tafel slopes distributed in the low and high overpotential domains was observed. Abnormal Tafel slopes (b ≠ 120 mV) obtained for the primary water discharge step during water electrolysis were interpreted considering the apparent charge transfer coefficient (α apa). Optimum conditions for the ozone production were obtained for the less rough β-PbO2 electrode immersed in a sulfuric acid solution (1.0 mol dm−3) containing KPF6 (30 × 10−3 mol dm−3), where the current efficiency of 15 mass % for the ozone production was obtained.

Comparison of degradation mechanism of electrochemical oxidation of di- and tri-nitrophenols on Bi-doped lead dioxide electrode: Effect of the molecular structure

In the present work, the effect of molecular structures of di- and tri- nitrophenols on electrochemical degradation has been investigated on Bi-doped lead dioxide electrodes in terms of cyclic voltammetry and bulk electrolysis. The results of SEM and AFM displayed a porous structure with small-sized crystal particles and compact crystalline structure of Ti/Bi-PbO2. These nitrophenols were believed to be mainly degraded by means of indirect oxidation due to the low anodic oxidation currents observed in cyclic voltammetries and large amount of oxidants. And the absence of polymeric adhesive compounds formed and deposited on the surface of electrodes indicated the high electrocatalytic activity of Ti/Bi-PbO2 for decomposing organics. Within the present experimental conditions used, almost complete elimination of nitrophenols was achieved. The electrochemical oxidation of them followed in the order: 2,6-dinitrophenol>2,5-dinitrophenol>2,4-dinitrophenol>2,4,6-trinitrophenol. The relationship between electrochemical oxidation rate and the molecular structure of nitrophenols was discussed. The results of LC/MS and HPLC suggested that three kinds of intermediates were generated, i.e., polyhydroxylated intermediates, reduction products of nitrophenols and carboxylic acids. The possible degradation pathways of nitrophenols were proposed. The denitration and substitution by hydroxyl radicals on aromatic rings seemed to be the first stage. As a consequence, the formation of polyhydroxylated intermediates took place. These compounds were successively oxidized into catechol, resorcinol and hydroquinone, as well as reduced to aminophenols, followed by the opening of aromatic rings and the formation of a series of carboxylic acids. Finally, these carboxylic acids were oxidized into CO2 and H2O.