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In this study, a zeolite-doped PbO 2 (Zeo-PbO 2) anode was fabricated via electrodeposition technology for electrochemical oxidation of m -nitrophenol (m -NP). The results of characterization revealed that doping zeolite efficiently promoted the oxygen evolution potential and active sites of PbO 2 anode, thereby higher performance to generate •OH radical and degrade the m -NP. The •OH radical was confirmed to be the primary contributor to the electrochemical oxidation of m -NP by scavenging tests. Thus, the effect mechanism of current density, supporting electrolyte, and initial pH on the removal of m -NP in the electrochemical oxidation process was explored by the generation of •OH radicals at different conditions. Based on the vulnerable sites of m -NP to the attack of •OH radical supposed by the theoretical calculation and degradation intermediates identified by GC-MS and IC, the degradation pathways of m -NP in the electrochemical oxidation process were speculated. Besides, the good recyclability and stability of Zeo-PbO 2 anode were exhibited in consecutive m -NP degradation, •OH generation experiments, and accelerated life tests. [Display omitted] • Doping Zeolite boosted the electroatalytic activity of PbO 2 anode. • Current, pH and supporting electrolyte influenced the yield of •OH. • Theoretical calculation and experimental analyses revealed the degradation pathway of m-NP. • The Zeo-PbO 2 anode offered higher stability compared to pure PbO 2 anode. [ABSTRACT FROM AUTHOR]

Coking reverse osmosis concentrated water contains refractory organic pollutants. If not treated, it will generate hazardous solid waste that cannot be utilized in the subsequent evaporation and crystallization process. In order to effectively remove organic substances from coking reverse osmosis concentrated water, Ti/PbO 2 electrode, Ti/Ce,Nd-PbO 2 electrode, and Ti/P(ANI-co-Py)/Ce,Nd-PbO 2 electrode were prepared. The electrodes were characterized by scanning electron microscopy, X-ray diffraction spectroscopy, and X-ray photoelectron spectroscopy, revealing that the average crystal grain size of lead dioxide on the surface of the Ti/P(ANI-co-Py)/Ce,Nd-PbO 2 electrode is 29.58 nm. The electrochemical performance of the electrodes was tested using cyclic voltammetry and electrochemical impedance spectroscopy, which showed oxidation peaks at 1.37 V, 1.81 V, and 2.1 V for the Ti/P(ANI-co-Py)/Ce,Nd-PbO 2 electrode, with a charge transfer resistance of 56.34 Ω. Accelerated life test indicated that the Ti/P(ANI-co-Py)/Ce,Nd-PbO 2 electrode has an accelerated lifespan of 1050 min. The effects of interelectrode distance, pH value, current density, and other factors on the electrocatalytic oxidation of 3,5-di-tert-butylphenol by the Ti/P(ANI-co-Py)/Ce,Nd-PbO 2 electrode were investigated, achieving a removal efficiency of 98.67 % under optimal conditions. Performance analysis of the Ti/P(ANI-co-Py)/Ce,Nd-PbO 2 electrode demonstrated good stability. Treatment of actual coking reverse osmosis concentrated water using the Ti/P(ANI-co-Py)/Ce,Nd-PbO 2 electrode resulted in removal efficiencies of 87.76 %, 47.92 %, and 77.42 % for COD, TOC, and UV 254 , respectively. The current efficiency and energy consumption of electrocatalytic degradation of coking reverse osmosis concentrated water were 9.38 % and 0.15 kWh/g COD. This study provides a better treatment solution for the degradation of organic matter in coking reverse osmosis concentrated water. [Display omitted] • The intermediate layer P(ANI-co-Py) has improved the lifespan and the stability of the lead dioxide electrode. • Doping Ce and Nd into the PbO 2 layer improves the electrocatalytic performance of the lead dioxide electrode. • The conditions for degradation of 3,5-di-tert-butylphenol were optimized on the Ti/P(ANI-co-Py)/Ce,Nd-PbO 2 electrode. • The mechanism of 3,5-di-tert-butylphenol degradation on the Ti/P(ANI-co-Py)/Ce,Nd-PbO 2 electrode was investigated. • An analysis was conducted on the electrode's reusability and practical application potential. [ABSTRACT FROM AUTHOR]

To lengthen the lifetime and extend the potential commercial applications of lead dioxide electrode. Herein, PbO 2 –TiO 2 heterostructured electrodes were fabricated via direct current electrodeposition and the surface of the electrode was characterized by electron microscopy (EDS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The PbO 2 –TiO 2 heterostructure electrode could produce an obvious photocurrent under UV irradiation, indicating a photoelectrocatalytic reaction. The PbO 2 –TiO 2 heterostructured electrode was examined using density functional theory calculations(DFT). Work function(WF) confirmed that the applied electric field is conducive to the movement of photoelectrons, which promotes the photoelectrocatalysis effect. The nudged elastic band(NEB) results showed that the PbO 2 –TiO 2 heterostructure electrode can promote the formation of •OH by reducing the activation barrier. The PbO 2 –TiO 2 electrode was used as an anode to treat P-aminophenol (PAP) wastewater simulated wastewater and real PAP wastewater via photoelectrocatalytic degradation. The PbO 2 –TiO 2 electrode effectively removes chemical oxygen demand (COD) from actual wastewater was 54.93 %,The after-treated Pb2+ concentration (0.037 mg·L−1) was lower than China's wastewater discharge standard (1 mg·L−1). Finally, the degradation pathway of PAP was determined based on the intermediates detected using gas chromatography–mass spectrometry and the reactive sites of PAP were predicted using the Fukui function.These results suggest that the photoelectrocatalysis degradation of PAP using electrodes is feasible. • PbO 2 –TiO 2 electrode can improve the photoelectrocatalysis performance. • The applied electric field is conducive to the movement of photoelectrons. • The degradation pathway of P-aminophenol wastewater was determined. • Reduce the electrode activation barrier to promote the formation of •OH. [ABSTRACT FROM AUTHOR]

The PbO 2 /Co 3 O 4 composite electrodes were synthesized using the composite co-deposition method, which involved the incorporation of Co 3 O 4 nanoparticles into a PbO 2 coating. These composite electrodes were employed as anodes for phenol electrooxidation in wastewater treatment. The results demonstrate that the PbO 2 /Co 3 O 4 composite electrode exhibits a three-dimensional porous structure, leading to a significant increase in the electrochemically active surface area. Electrochemical measurements indicate that the composite electrode achieves a minimum oxygen evolution potential of 526.5 mV. Moreover, the electrode facilitates the indirect degradation of phenol, even at low voltage (0.45 V). The unique structure, improved conductivity, and enhanced surface area of the electrode contribute to its exceptional performance in phenol degradation. Additionally, this approach offers the potential for synergistic integration with other treatment methods, providing a sustainable and energy-efficient solution for removing persistent organic compounds from wastewater. [Display omitted] • The PbO 2 /Co 3 O 4 has a high electrochemically active surface area. • PbO 2 is served as a conductive platform for Co 3 O 4. • The PbO 2 /Co 3 O 4 composite has low evolution potential. • The oxidation of phenol at 450 mV using PbO 2 /Co 3 O 4 anode. • This approach reduces energy in a hybrid treatment process. [ABSTRACT FROM AUTHOR]

The impact of deposition process parameters (temperature, current density, Pb2+ concentration, and time of deposition) on morphology, electrical resistance, and discharge performance of a graphite/PbO2 cathode in a PbO2/zinc primary battery was investigated. The morphology, architecture, and phase composition of the PbO2 deposits were studied by FESEM, EDX, and XRD. The AC impedance and discharge tests were utilized for the exploration of the interfacial process and discharge performance of PbO2 deposits. The results indicate that the increment in temperature and decrease in current density leads to increased growth of PbO2 deposits with mainly ß phase, formation of porous architecture, and a decrease in the charge transfer resistance (Rct). Also, with an increase in the deposition time to 30 min the Rct is increased due to the formation of PbO2 deposit with more uniform and compact structure. The deposition from 0.1 mol l1 Pb2+ solutions results in the formation of flower-like grains, a more porous surface, and lower Rct. However, because of concentration polarization, the PbO2 deposit prepared from 0.5 mol l1 of Pb2+ solutions, 55 °C temperature, 40 mA cm2 current density, and 15 min deposition time shows the best discharge performance. [ABSTRACT FROM AUTHOR]

The electrochemical oxidation of nitrofurazone with SnO2, doped by platinum group metals, and pure PbO2 has been investigated. The oxidation rate of nitrofurazone with PbO2-anode is 5.3 times higher compared to doped SnO2 anodes. It was found that the presence of 1; 2 and 3 g l-1 NaCl in electrolyte affects the efficiency of the electrooxidation process in the case of doped SnO2 anodes, the oxidation rate of nitrofurazone increases by 2.3; 3.7; 5.8 times, respectively. Using of doped SnO2 in chloridecontaining media allows one to achieve the same rate of destruction of nitrofurazone as when using lead dioxide. Moreover, SnO2 doped electrodes are characterized by the production of a large number of hypochlorous acid and have a higher service life compared to PbO2 in such harsh conditions. [ABSTRACT FROM AUTHOR]

A study on the influence of sulphuric acid (H2SO4) concentration on the electrochemical activity, phase composition, structure and morphology of the lead dioxide (PbO2) particle thereby its impact on performance of battery was carried out. For the formation process, cells made up of two positive and two negative plates with graphite powder/acetylene carbon and H2SO4 with different concentrations (1.05, 1.15 and 1.25 specific gravity (SG) are used. During the soaking period, lead oxide (PbO) and basic lead sulphate (PbO.PbSO4) react with H2SO4, and sulfation of the plate starts. These processes changes the structure and morphology of the crystals in the cured paste. The results showed that the concentration of H2SO4 decreases gradually during soaking indicating that H2SO4 is reacting with PbO present in the paste. After the formation process the phase composition and morphology of active material are characterized using X-ray powder diffraction (XRD) and Scanning Electron Microscope (SEM) studies respectively. After formation, the concentration of H2SO4 is altered to 1.24 SG. The simulated 2 V lead-acid cells are subjected to capacity and service life measurement. The results proved indeed the acid SG in formation alters the structure of active material and life of battery. [ABSTRACT FROM AUTHOR]

Pulsed and constant direct current electrodepositions were applied to synthesize PbO 2 -IrO 2 nano-composites on Ti substrate. By compositing PbO 2 with nano-sized IrO 2 particles, a suitable anode was prepared for zinc electrowinning that decreases the electrocatalytic activity for oxygen evolution reaction overpotential (OER) while increasing the electrochemical active surface area and the electrocatalytic activity for OER. To provide PbO 2 -IrO 2 nano-composites on Ti substrate with Sb 2 O 3 interlayer, current density, temperature, and time of anodization are optimized using the one-at-the-time method. The optimal condition for the anode involves a DC time of 1 h, incorporating 2 g L-1 of IrO 2 nanoparticles, maintaining a current density of 50 mA cm− 2 for the DC mode, and setting the pulse off-time (t off) to 770 ms. Based on the electrochemical evaluations in a simulated zinc electrowinning electrolyte, the effect of IrO 2 nanoparticles on the catalytic activity of Ti/β-PbO 2 anode for OER was determined. Anodic polarization curves showed that the OER overpotential of PbO 2 -IrO 2 micro-composite and PbO 2 -IrO 2 nano-composites at a current density of 10 mA cm-2 decreased to 0.471 V, respectively, compared to 0.711 V for pure PbO 2. The Nyquist plots in the OER zone confirm that the PbO 2 -IrO 2 nano-composite anode exhibits the lowest Rct 2.79 Ω compared to 6.0 Ω and 9.46 Ω for PbO 2 -IrO 2 micro-composite and pure PbO 2 , which can be attributed to the presence of electro-catalytic IrO 2 nanoparticles. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel Ti/PbO2-Bi-PTh composite electrode was successfully prepared by electrodeposition and applied in electrochemical degradation of phenol. The Ti/PbO2-Bi-PTh electrode was characterized by XRD, SEM, AFM, LSV, CV and EIS. Results showd that the electrode has a fine and compact surface structure, higher oxygen evolution potential (OEP, 2.42 V) and low charge transfer resistance (51.00 Ω). The electrode also exhibited excellent electrochemical oxidation activity on the degradation of phenol (1000 mg l−1) with degradation efficiency of 100% and TOC removal rate of 93.58% achieved in 60 min and 180 min, respectively. In addition, possible mechanism of phenol degradation on the electrode was proposed by analyzing the intermediate products with GC-MS. Noticeably, the Ti/PbO2-Bi-PTh electrode displayed excellent stability and high electrocatalytic performance after 10 cycles, indicating its promising application in the phenolic wastewater treatment. [ABSTRACT FROM AUTHOR]

• Graphite/β-PbO2 anode was used to improve the biodegradability of textile wastewater. • Process optimization by genetic algorithm. • Electrochemical degradation mechanism of methylene blue. • Reusability and stability of graphite/β-PbO 2 anode was investigated. An anodic oxidation process with graphite anode coated with lead dioxide (G/β-PbO 2) was optimized for the degradation of methylene blue (MB) and the treatment of real textile wastewater. The G/β-PbO 2 anode was prepared by the electrochemical precipitation method. The scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses confirmed the successful coating of graphite substrate with the β-PbO 2 film. The effect of four independent variables including pH, reaction time, current density, and electrolyte concentration of Na 2 SO 4 on the performance of the electrochemical oxidation system was modeled by using a complete central composite design and was then optimized by genetic algorithm method. The accuracy of the proposed quadratic model by CCD was confirmed with p-value <0.0001 and adj-R2 > 0.9. The optimum conditions for solution pH, reaction time, current density, and Na 2 SO 4 electrolyte concentration were obtained to be 5.75, 50 min, 10 mA/cm2, and 78.8 mg/L, respectively. In these conditions, the experimental removal efficiencies of MB using G/β-PbO 2 and graphite anodes were 96.2% and 68.3%, respectively. The electrochemical removal of MB using both G/β-PbO 2 and graphite anodes well followed the pseudo-first-order reaction (R2 > 0.9). Cyclohexane, cyclohexa-2,5-dien-1-ylium, and N-(sec -butyl) aniline were the most abundant intermediates identified by LC-MS analysis. However, the complete mineralization of MB was achieved in 60 min. The optimized anodic oxidation process successfully improved the biodegradability of real textile wastewater (B O D / C O D > 0.4). [ABSTRACT FROM AUTHOR]

The electrochemical behavior of PbO 2 /PbSO 4 electrode is investigated in 4.5 M H 2 SO 4 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 PbO 2 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 PbO 2 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 R ct. 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 PbO 2 formation. [ABSTRACT FROM AUTHOR]

PbO2-polyelectrolyte composite materials with a content of polyelectrolyte up to 13 wt% are formed by electrochemical deposition of PbO2, depending on the solution composition and the deposition conditions. Several assumptions concerning the mechanism of the formation of composites that taking into account the oxygen-containing species of lead non-fixed on the surface, located in the near-electrode zone have been proposed. The shape and size of the PbO2 crystals is altered by the presence of polyelectrolyte. The surface is more uniform and the crystals are smaller, there is not a pronounced crystallographic orientation, however the phase content remains practically the same as in the undoped sample. When using composite materials based on lead dioxide containing polyelectrolyte, selective changes in the overvoltage of oxygen evolution and electrochemical conversion of organic substances into aliphatic non-toxic compounds are observed. In this case, the electrocatalytic activity of composite materials depends on the nature and content of the polyelectrolyte additive in the oxide. [ABSTRACT FROM AUTHOR]

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Present study proposed the preparation, characterization and application of cobalt (Co), neodymium (Nd), and cerium (Ce) modified lead (PbO 2 ) electrodes. Morphological and structural properties of as-prepared electrodes were determined by SEM, XRD, and XPS. Linear sweep voltammetry (LSV) and accelerated life test were used to determine the electrocatalytic activity and stability of as-prepared electrodes. Higher oxygen evolution potentials (OEP) and longer service life were used to confirm the maximum electrocatalytic activity of Nd and Ce PbO 2 electrodes. The electro-oxidation ability was examined with Acid Orange 7 (AO 7) treatments. Cyclic voltammetry (CV), UV–visible, and fluorescence spectrophotometric analysis of AO 7 treatment were confirmed that Nd and Ce PbO 2 have excellent oxidation ability, higher AO 7 removal efficiency and higher total organic carbon (TOC) with a good correlation of instantaneous current efficiency (ε inst ) and higher hydroxyl radical ( • OH) generation rate, respectively. The effect of removal parameters was optimized with Ce PbO 2 electrode. Results of AO 7 and TOC removal were reached up to 100% and 93.7%, respectively, after 180 min of electrolysis at the optimum condition of 0.2 M Na 2 SO 4 concentration, 100 mg L –1 initial dye concentration, solution pH 7.0 and 20 mA cm –2 applied current density. Reusability and safety test analysis were used to detect the best results of AO 7 degradation with Ce PbO 2 electrode. Mass spectroscopy and ion chromatography (IC) were used to detect the formation of intermediates by-products. Finally, based on the detection of reaction by-products, a plausible degradation pathway including radical reactions, ring opening and de-nitrification was proposed. [ABSTRACT FROM AUTHOR]

Shape-controlled nanomaterials of PbO 2 have attracted considerable attention in designing highly efficient electrocatalyst, since the physicochemical properties of PbO 2 vary from their structure and morphology. PbO 2 materials demonstrating promising ability in electrochemical ozone production (EOP) have attracted the focus of research recently, and therefore boost the strategical improvement in their key performance, such as electroactivity, current efficiency and space-time yield. In this work, the PbO 2 crystals with controllable structures of rod-like, sphere-like as well as star-like PbO 2 were acquired to explore their physicochemical properties and EOP performance systemically. Among the samples, PbO 2 nanorods, benefitting from their abundant active surface chemisorbed oxygen, exhibit relatively high electrocatalytic activity towards EOP. Such structural feature is beneficial for triggering the generation of a rapid charge, improving mass transfer, and subsequently enhancing the corresponding electrocatalytic reactions. A maximum EOP current efficiency of 14% was achieved by the PbO 2 nanorod electrode at a cell potential of 4.0 V corresponding to a specific electric energy consumption of 101.53 kWh·(kg·O 3)−1. Overall, an in-depth understanding of the nanostructure–performance relationship of PbO 2 and EOP performance is demonstrated in this work, which can provide an insight into the rational design of PbO 2 for the EOP. • PbO 2 with rod-, sphere-, and star-like morphologies were prepared. • Physicochemical properties and EOP performance of PbO 2 are systemically explored. • PbO 2 nanorods exhibit relatively high electrocatalytic activity towards EOP. [ABSTRACT FROM AUTHOR]

A novel porous PbO2-ZrO2 nanocomposite electrode was successfully prepared by bubbles template composite electrodeposition methods for the first time. Scanning electronic microscopy (SEM) and X-ray diffraction (XRD) results show that the novel porous PbO2-ZrO2 nanocomposite electrodes have the three-dimensional porous structure and smaller crystal sizes than planar PbO2-ZrO2 nanocomposite electrodes. ZrO2 nanoparticles can be observed on the electrodes. The cyclic voltammetry measurement show that the electrochemical active surface area of porous PbO2-ZrO2 nanocomposite electrodes is 3 times than that of planar PbO2-ZrO2 electrodes. In the electrocatalytic oxidization process of crystal violet, the color and COD removal efficiency on the porous composite electrodes is 99.8% and 69.2% after 90 min. The degradation process follows pseudo-first-order kinetics. The rate constant for porous composite electrodes can reach 0.04916 min-1, which is 4.5 times than that for planar composite electrodes (0.01188 min-1). Moreover, the three-dimensional porous structure can enhance the generation capacity of hydroxyl radicals. The experiment results illustrate that the porous PbO2-ZrO2 nanocomposite electrodes have a great application potential in the pollutant degradation fields. [ABSTRACT FROM AUTHOR]

Modified PbO 2 electrodes were prepared by electrodeposition in the presence of ionic liquid 1-ethyl-3-methyl-imidazolium tetrafluoroborate ([Emim]BF 4 ). The electro-catalytic performance of the prepared electrodes for the electrochemical degradation of phenol in aqueous solution was investigated. The COD removal of phenol simulated wastewater followed pseudo-first-order rate kinetics. The rate constant with [Emim]BF 4 -modified PbO 2 electrodes was 0.007 39 min −1 , higher than 0.003 83 min −1 obtained with non-modified PbO 2 electrodes. The microstructure of the electrodes was characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical properties were investigated by Mott-Schottky, steady-state polarization and linear sweep voltammetry techniques. Results indicate that PbO 2 coatings with compact and regular morphology, a higher degree of crystallinity and higher content of oxygen in crystal lattice are anodically grown on Ti substrate from electrolyte containing [Emim]BF 4 . Steady-state polarization tests show that oxygen evolution overpotential on modified electrodes is significantly higher than that on non-modified ones. Mott-Schottky tests reveal a markedly lower content of oxygen vacancy in modified PbO 2 samples as compared with the non-modified ones. It is suggested that the enhanced electro-catalytic activity of the [Emim]BF 4 -modified PbO 2 electrodes towards phenol degradation arises largely from its lower content of oxygen vacancy, which decreases the probability of oxygen transferring from more effective •OH into less desirable O lat at the electrode surface. [ABSTRACT FROM AUTHOR]

The three-dimensional porous structure PbO2 electrodes (3D-PbO2) were successfully prepared in the lead nitrate solution by potentiostatically electrodeposition methods using oxygen bubbles as dynamic template. The morphology and structure of 3D-PbO2 electrodes were investigated by scanning electronic microscopy (SEM) and X-ray diffraction (XRD). Compared with the traditional PbO2 electrodes (Flat-PbO2), 3D-PbO2 electrodes possess the three-dimensional porous structure and finer grain size. The electrochemical properties of 3D-PbO2 electrodes were investigated by linear sweep voltammetry (LSV), cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). The 3D-PbO2 electrodes show larger electrochemical active surface area, lower charge transfer resistance and higher oxygen evolution overpotential than Flat-PbO2 electrodes. In the electrocatalytic degradation process of malachite green, the degradation rate constant of 3D-PbO2 electrodes (0.05189 min-1) was 5.8 times than that of Flat-PbO2 electrodes (0.00889 min-1). [ABSTRACT FROM AUTHOR]

Lead acid battery has been one of the most important secondary battery for industrial use. It has been revealed that the corrosion of current collector (CC) is a critical factor to determine the battery life. In this study, focusing on the local cell reaction (LCR) between the cathode active material and CC during the rest time period, we investigate the capacity fading mechanism of the lead acid battery. Only when the lower potential material in comparison with the cathode active material is employed as CC, formation of α-PbO2 is detected accompanied by the capacity degradation. We clarified that LCR of CC results in the α-PbO2 formation, which correlates with the degradation of the cell performance. [ABSTRACT FROM AUTHOR]

Hydrometallurgical route has been widely studied for its clean and controllability in recovering waste lead-acid battery. However, the current challenges are to reduce chemicals consumption and enhance the economic benefit. Therefore, we presented a sustainable approach for preparing lead oxide from the spent lead grid and lead paste based on sodium nitrate reusing. Results showed that the process indirectly and mildly completed the atomic economic reaction between lead and lead dioxide by sodium nitrate, dramatically reducing the reagents consumption. The reaction rate of the process was depended on the interfacial chemical reaction between lead grid and sodium nitrate. Through controlling the thermodynamic conditions, 99.53% of zero-valent lead (lead grid) was transformed into the layered orthogonal β-lead oxide with merely 0.0494% impurities, and 99.79% of tetravalent lead (lead dioxide in the lead paste) was converted into divalent lead (lead sulfate) in sulfuric acid solution. Afterwards, the lead sulfate was desulfurated followed by thermal decomposition, generating the rod-shaped tetragonal α-lead oxide with only 0.0233% impurities. Moreover, the products β-lead oxide and α-lead oxide used in batteries as anode materials showed excellent electrochemical performance with 482 and 518 charge/discharge cycles, respectively. Additionally, the pilot experiments proved the technological and economic feasibility of the process with a profit of $667.81/ton lead oxide. These results provide an economical and eco-friendly method for synergistically recycling waste lead grid and lead paste. [Display omitted] • NaNO 3 can promote the coupling reaction between Pb and PbO 2 without consumption. • PbO with excellent electrochemical properties is obtained based on NaNO 3 recycling. • A co-treatment way of lead paste and lead grid with low cost is developed. [ABSTRACT FROM AUTHOR]

In this paper the results are presented of a study on the use of electro-catalytic coating of PbO2 on Ti/SnO2 substrate. The experiments were conducted using continuous and pulse DC electrodeposition in a nitrate type electrolyte. Electrodeposition parameters, such as current density and electrolyte temperature were changed to produce a coating with a high surface roughness, small crystal size and high active surface area. The samples were studied using a number of techniques that included scanning electron microscopy (SEM), roughness measurement and cyclic voltammetry (CV). The results showed that a combination of 65°C and 33 mA cm−2 are the optimum temperature and current density that yield a good coating of pure β-phase. The morphology of coating under these electrodeposition conditions included fine flakes with a length about 0·75-10 μm and compact crystallites. Scanning tunnelling microscopy (STM) observation of the surface revealed that the coating also included PbO2 nano-particles with an average diameter in the range of 7-21 nm. [ABSTRACT FROM AUTHOR]

The influence of cerium on lead dioxide electrodeposition process on a glass carbon electrode (GCE) from lead nitrate solution was studied by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Cerium exhibit an inhibition effect on the lead dioxide electrodeposition process. Instantaneous nucleation mechanism can be found for lead dioxide electrodeposition according to Scharifker-Hills' model with three-dimensional growth, which is not influenced by the addition of cerium. The morphology and structure of Ce-doped PbO2 electrodes were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the adulteration of cerium can greatly decrease grain size and make the films more compact. Accelerated lifetime tests demonstrate that the adulteration of cerium can highly lengthen the service life of Ce-doped PbO2 electrode in its practical application. Methylene blue degradation experiments reveal that the Ce-doped PbO2 electrodes possess excellent electrocatalytic activity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Carbon nanotube and Bi co-doped PbO2 electrode (CNT-Bi-PbO2) was prepared. [•] The oxygen evolution overpotential of PbO2 electrode was increased by co-doping. [•] CNT-Bi-PbO2 electrode showed obviously higher activity than pure PbO2 electrode. [•] The service life of CNT-Bi-PbO2 electrode was 4.16 times that of pure PbO2 electrode. [ABSTRACT FROM AUTHOR]

A type of redox flow battery, based on lead (II) dissolved in the electrolyte, has emerged as possible system for energy storage. However, the formation of lead dendrite and the evolution of hydrogen in the last stage of charge have limited the application of soluble lead flow batteries. A comparison study on electrochemical behavior of polyaniline (PANI) suspension indicates that the electrochemical response of PANI suspension in flowing mode significantly differs from that in static state, exhibiting good charge transfer property due to continuous renewal of PANI microparticles by the flow of suspension. Therefore, PANI microparticle suspension is used as anode material to fabricate the lead dioxide flow battery. The cycle performance of the lead dioxide flow battery has been improved by replacing the lead electrode with the flowable PANI, and the average of discharge capacity loss is only 0.05% per cycle during 60 cycles. The coulombic efficiency shows no significant change with the number of cycles over the experiment. Furthermore, the working current density of 20 mA cm-2 in the proposed battery system has been achieved, which is greatly enhanced compared with the conventional PANI film batteries. [ABSTRACT FROM AUTHOR]

Abstract: The electrochemical degradation of the Disperse Orange 29 azo dye in a filter-press flow cell using a Ti–Pt/β-PbO2 as anode was investigated by experimental design for the variables current density, pH, [NaCl], and temperature. The electrochemical system was modeled by the charge required to attain 90% decolorization (Q 90) and the chemical oxygen demand removal after 120min of electrolysis (COD 120). The best conditions for Q 90 were neutral to slightly alkaline solutions with low values of [NaCl] (<1.0gL−1). On the other hand, slightly acidic to neutral conditions with higher values of [NaCl] (1.2–1.7gL−1) yielded the highest COD 120 values. These differences were ascribed to the possible formation of organochloride compounds that may lead to erroneous COD values. A total mass loss of only 0.1% was obtained during an accelerated life test of the Ti–Pt/PbO2 anode. Low levels of [Pb2+] were attained in neutral to alkaline conditions [Copyright &y& Elsevier]

The electrochemical characteristics of a soluble lead flow battery are key factors for the improvement of its cyclic lifetime and efficiency. In this work, we suggested aqueous solution of Pb(BF 4) 2 and HBF 4 as the electrolytes of soluble lead flow battery and observed the kinetic behavior of the electrode by cyclic voltammetry of the cyclic lifetime, quantum efficiency and voltage efficiency of the SLFB with respect to concentration of the electrolyte. Both the density and viscosity of the electrolyte increase with an increasing [Pb(BF 4) 2 ]. The conductivity exhibits a peak at 1.5 mol/L Pb(BF 4) 2 when [HBF 4 ] is below 1.0 mol/L. According to the cyclic voltammetry, the electrode process is fast with a low overvoltage and no additional reactions for the aqueous solution with 1.5 mol/L Pb(BF 4) 2 and 0.25 mol/L HBF 4. Overall, for the aqueous solution of 1.5 mol/L Pb(BF 4) 2 and 0.25 mol/L HBF 4 , the battery showed a best performance with the cyclic lifetime being 48 times, the average quantum efficiency 88%, the voltage efficiency 70% and the battery efficiency 62%. These results are promising for fresh parameters of the electrolyte that could play a major role for the improvement of SLFBs. [ABSTRACT FROM AUTHOR]

A lead dioxide anode doped with the praseodymium was prepared by a simple method of cyclic voltammetry (CV). Then the major work focused on the investigation of the different electrochemical performance of praseodymium doped lead dioxide anode by CV method and coelectrodeposition (CD) method. The spectral methods and electrochemical measurements were applied to analyze the physicochemical properties of the Ti/PbO2-Pr2O3 anodes prepared by the two methods. The XRD and XPS showed the Pr2O3 was successfully doped into the PbO2 film by CV method. Comparative studies between the two doped anodes indicated that the Ti/PbO2-Pr2O3 (CV) anode had a larger surface, a better stability and exhibited a longer service life. The experiments of degradation methyl orange as a model dye wastewater suggested that comparing with Ti/PbO2-Pr2O3 (CD) anode, Ti/PbO2-Pr2O3 (CV) anode had excellent electrocatalytic performance and low energy consumption. Thus, the CV modification method should be considered as a simple and promising modification method for the rare earth elements doped on the surface of many other anodes [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A simplified profile imitating the micro-hybrid driving mode is performed on the lead acid batteries to evaluate the effect of the modified negative electrode design with half carbon paste as part of negative plate under high rate partial-state-of-charge operation (HRPSoC). In this work, we report that the half side carbon paste replacing half of the spongy lead negative paste in negative plate has significantly improved the cyclability of lead-acid batteries under high rate partial-state-of-charge operation. This is mainly attributed to the high specific surface area and conductivity of the carbon black. In addition it minimises the formation of irreversible lead sulfate at the negative plate. Thus, half carbon black on negative plate in lead acid battery eventually improves the performance characteristics of lead-acid cells under HRPSoC cycling. [ABSTRACT FROM AUTHOR]

High energy ball-milling (HEBM) of pure PbO2 and of mixtures of PbO2 with BaSO4 was performed as a function of time. The powders were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy, while the intrinsic electrochemical properties of the powders were assessed in IM H2SO4 using a cavity microelectrode (CME). During milling, there is a transition from a tetragonal structure (β-PbO2) to an orthorhombic structure (α-PbO2) and, after 1 h, the powder is composed of ∼80 wt% α-PbO2. The addition of BaSO4 doesn't influence the kinetics of the β- to α-PbO2 transition. Also, during milling, the crystallite size of β-PbO2 decreases from 25 to 8 nm, while the crystallite size of α-PbO2 is constant at 14 nm. During the first few hours of milling, there is a 50 mV shift of the potential corresponding to the maximum reduction and oxidation peak current towards less negative and positive values, respectively. This effect is emphasized by the addition of BaSO4, indicating that the reversibility of the PbSO4/PbO2 system is increased. This is thought to arise as a consequence of a reduction of the crystallite size and the presence of BaSO4. [ABSTRACT FROM AUTHOR]

In this study, the electrocatalytic synergy of the graphite/β-PbO 2 anode and granular activated carbon (GAC) particles electrodes for bisphenol A (BPA) degradation are investigated in a three-dimensional electrochemical reactor (3DER). The graphite/β-PbO 2 anode was prepared by anodic deposition method and the electrocatalytic properties of lead oxide film were studied by FESEM, XRD, EDX-mapping, linear sweep voltammetry and accelerated lifetime test techniques. The effect of five independent variables including pH, Na 2 SO 4 concentration, current density, GAC amount, and reaction time on the system response was optimized by an orthogonal central composite-genetic algorithm (OCCD-GA). The results showed that β-PbO 2 crystals were deposited as completely compact pyramidal clusters on the graphite surface. In addition, the service life and oxygen evolution potential (OEP) for the electrocatalytic layer of β-PbO 2 were 90 h and 2 V, respectively. Based on the developed quadratic model (R2 > 0.99 and p-value < 0.0001), the optimal points for pH, Na 2 SO 4 concentration, current density, GAC amount, and reaction time were predicted to be 4.6, 0.074 mol L−1, 35.7 mA cm−2, 25 g, and 80 min, respectively. Under optimal conditions, BPA removal efficiency in 3DER system and separate application of electrocatalytic degradation and GAC were obtained 98.8%, 72.2% and 9.75%, respectively. Thus, the electrocatalytic synergy of 3DER system due to lead oxide layer and GAC particle electrodes in BPA degradation was calculated to be 35.5%. LC-MS analysis was used to identity the intermediates formed during BPA degradation. The final degradation intermediates were short-chain acids including adipic acid, malonic acid and, acetic acid. [Display omitted] • A 3DER system with Graphite/β-PbO 2 and GAC particle electrode was optimized for mineralization of Bisphenol A. • Process modeling and optimization by full orthogonal CCD-Genetic algorithm method. • Graphite/β-PbO 2 anode was prepared by anodic deposition method. • A noticeable electrocatalytic synergy was observed during Bisphenol A degradation. • Possible pathways of electrochemical degradation of Bisphenol A were proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Interaction of sulfur dioxide with superalkalis, FLi 2 , OLi 3 and NLi 4 has been investigated. • All the superalkalis are able to reduce SO 2. • High binding energy values elucidate the stability of the complexes formed between the superalkalis and SO 2. • The size of superalkalis plays an important role in SO 2 -reduction. Sulfur dioxide (SO 2) is considered to be one of the major air pollutants. It causes damages to the environment and human health. Thus, removal of sulfur dioxide from the atmosphere is a necessary task. Herein, we report a systematic study on the reduction of SO 2 using three typical superalkalis, FLi 2 , OLi 3 and NLi 4 at density functional theory level. The interaction between superalkali (SA) molecules and sulfur dioxide leads to the formation of SA-SO 2 complexes. High binding energy values dictate the stability of the formed complexes. Accumulation of negative charge on SO 2 molecule in the SA-SO 2 complexes indicates that sulfur dioxide can be reduced with the aforesaid superalkalis. We have also observed that the size of the superalkalis plays more important role than their ionization energies in the reduction of sulfur dioxide. [ABSTRACT FROM AUTHOR]

• Introducing a new catex polymer-gold nano particles composite modified electrode. • Very sensitive in determination of paraquat in water and soil samples. • Large range of linearity and low LOQ. • No necessity for renewing the electrode surface. • Chemical and mechanical stability during analysis. A new catex polymeric-gold nanoparticle composite modified electrode for the determination of paraquat (PQ) in various samples is introduced. Fabrication of the electrode is based on casting a poly carboxylic polymer on a glassy carbon electrode, which was prepared separately in an electrochemical system; after which electrodeposition of the gold particles on the surface of electrode took place. The morphology of the electrode surface was investigated by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrometry (EDS) and mapping. Chemical structure of prepared composite was studied by differential scanning calorimetry (DSC), Fourier-transform infrared spectrometry (FTIR), and H NMR spectrometry. The obtained results show that the prepared polymer is a weak catex with carboxylate groups. The presence of the gold particles in the composite enhanced the sensitivity of the electrode for the determination of paraqaut. The application of this electrode for determination of paraquat is based on the redox property of paraquat. The fabricated electrode shows a wide range of linearity (1.9 × 10−8−7.8 × 10-7 mol L-1) and LOQ (7.78 × 10-10). The mean, standard deviation and RSD for five repetitive determinations of paraquat (3.20 × 10-7 mol L-1) are 3.15 × 10-7 mol L-1, ±1.40 × 10−8 mol L-1 and 4.28 % respectively. This electrode was successfully applied for determination of paraquat in natural waters and soils. The obtained results were compared with the results of standard methods. The characteristic parameters of the offered method were compared with other electrochemical methods. [ABSTRACT FROM AUTHOR]