Cathode Area Research Articles

Mariculture wastewater treatment using electrochemically assisted submerged fixed bed bioreactor (E-SFBBR): Potential performance and pathways of nitrogen removal

Nitrogen discharged from mariculture industry leads to adjacent aquatic pollution. This study utilized an electrochemically assisted submerged fixed bed bioreactor (E-SFBBR) to treat carbon-limited saline mariculture wastewater and aimed to evaluate the performance and pathways of nitrogen removal by testing the effects of electrical stimulation and different current densities (CD). Electro-stimulation increased nitrogen removal performance of E-SFBBR from 1.1 to 2.2 g N m−2 d−1 to 3.0–3.4 g N m−2 d−1; CD of 0.10 mA cm−2 resulted in the highest N removal rate. Results of water quality at different depths and the batch experiment revealed the N removal pathways in E-SFBBR: in the cathode area, nitrogen removal was mainly attributed to the processes of denitrification and dissimilatory nitrate reduction to ammonia; and in the anode area, nitrification and autotrophic denitrification driven by sulfur or iron contributed to nitrogen elimination. These findings provided a promising method for enhancing N removal from carbon-limited mariculture effluents.

Understanding the Influence of Nanocarbon Conducting Modes on the Rate Performance of Lifepo4 Cathode in Lithium Ion Batteries

We report on an efficient and practical conducting mode built up by ternary conductive additive for boosting the electrochemical performance of LiFePO4 cathode in lithium ion batteries. The influence on the conductivity, rate capability as well as the continuous conductive paths of the resulting electrode is investigated. Carbon nanotubes (CNTs) with long-range electronic conduction are ultimately homogeneously dispersed (mono-dispersed) in electrode slurry, which connect the short-range conductive regions together formed by graphene sheets. Importantly, CNTs could provide more open channels for electrons and ions transportation, compared with the blocking function of graphene sheets. Herein, it is found that low contents of graphene sheet are unable to build up continuous conductive networks thus causing degraded rate capability compared with higher contents of them. Low-content graphene regions are then bridged by mono-dispersed CNTs to construct a complete conductive network, enable the hybrids having both an improved electrically conductivity and an electrons/ions open channels. Furthermore, combining a small number of carbon black as supplementary conducive point, an efficient and practical conducting mode called plane-to-line-to-point is demonstrated. Such conducting mode can construct both short-range/long-range electronic conduction and open ions channels, while also having conductive points all over the uncovered area of LiFePO4 cathode.

Influence of the interelectrode distance and the ratio of the cathode and anode areas on the formation rate and properties of MAO coatings

Influence of the interelectrode distance and the ratio of the cathode and anode areas on the formation rate and properties of MAO coatings

Study of a Dual-Mode Multibeam Interaction Circuit With Coaxial Structure for Ka-Band High-Power EIK

A dual-mode five-beam extended interaction klystron (EIK) with a coaxial structure is proposed that can stably obtain high output power. The TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\textit {mn}}$ </tex-math></inline-formula> mode with uniform angular distribution in the coaxial cavity can effectively interact with beams located at the peaks of the axial electric field. However, when the center radius of the cavity is enlarged to meet the cathode area requirements of high-power devices at high frequency, the interval between adjacent modes will rapidly decrease. Especially when combined with a multigap structure, the circuit will suffer from mode competition. This article describes a study of the beam–wave interaction characteristics of the multigap coaxial cavity driven by multiple beams, contributing to a stable circuit design. The results show that the appropriate mode selection for each cavity can increase the stability and efficiency of this device. A <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -band EIK with four cavities has been designed to show the circuit capability. The output cavity operates in the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">51</sub> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\pi $ </tex-math></inline-formula> mode, but the other cavities operate in the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\pi $ </tex-math></inline-formula> mode. The 3-D particle-in-cell (PIC) simulation predicts a power of 211.6 kW at 35.19 GHz with the beam parameters of a voltage of 42 kV and a total current of 15 A (3 A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times5$ </tex-math></inline-formula> ). The corresponding gain, electronic efficiency, and 3-dB bandwidth are 53.26 dB, 33.5%, and 50 MHz.

Research on the Metal Corrosion Process in the Sea Mud/Seawater/Atmosphere Interface Zone

Corrosion in the interface zone is a complicated local corrosion phenomenon. The conventional single-electrode method finds it difficult to obtain the kinetic information of corrosion occurrence and development process. In this paper, metal corrosion was studied by Wire Beam Electrode (WBE) technology on the interfaces of sea mud/seawater and seawater/atmosphere. The study found that the metal corrosion in the interface is a process of coupling a dual corrosion cell into a single corrosion cell. Initially, a corrosion cell is formed with the seawater/atmosphere interface acting as the cathode and the upper part of the metal in the seawater area as the anode. This is due to the oxygen concentration cell caused by the waterline effect. The cathode area is always enriched near the seawater/atmosphere interface. The lower part of the metal in the seawater area and the metal in the sea mud area are the anode and the cathode, respectively, of another corrosion cell. Along with the immersion time, the anodic area of the first corrosion cell gradually extends to the lower part of the metal in the seawater zone and finally the sea mud zone, resulting in the disappearance of the second corrosion cell. In the single corrosion cell stage, the seawater/atmosphere interface is the cathode area; the seawater area and the sea mud area are the anode areas, and the electrode adjacent to the cathode area becomes the anode area with the largest current density. During the whole experiment, the sea mud zone is a process of polarity transition from the cathode zone to the anode zone, and finally forms the anode zone of the whole electrode together with the anode zone in the sea zone.

Biochar-Terracotta Conductive Composites: New Design for Bioelectrochemical Systems

Research in the field of bioelectrochemical systems is addressing the need to improve components and reduce their costs in the perspective of their large-scale application. In this view, innovative solid separators of electrodes, made of biochar and terracotta, are investigated. Biochar-based composites are produced from giant cane (Arundo Donax L.). Two different types of composite are used in this experiment: composite A, produced by pyrolysis of crushed chipping of A.donax L. mixed clay; and composite B, produced by pyrolysis of already-pyrolyzed giant cane (biochar) mixed with clay. Electrical resistivity, electrical capacity, porosity, water retention, and water leaching of the two composites types (A and B) with 1, 5, 10, 15, 20, and 30 mass percentages of carbon (w/w) are characterized and compared. Less than 1 kΩ cm of electrical resistance is obtained for composite A with a carbon content greater than 10%, while physical and electrical performances of composite B do not significantly change. SEM micrographs and 3D microcomputed tomography of different composite materials are provided, demonstrating a different matrix structure of carbon in the terracotta matrix. The possibility of suitably decreasing electric resistance and increasing water retention/leaching of composite A opens the way for a new class of resistive materials that can be simultaneously used as electrolytic separators and as external electric circuits, allowing a compact microbial fuel cell design. A proof of concept of such an MFC design was provided for different tested composites. Although all the anolytes become anaerobic, only the MFCs equipped with the composite A30% were able to produce power, reaching the maximum power peak in correspondence to resistance of about 1 kΩ. The low, but significant, produced power (about 40 mW m−2, cathode area) confirm that the proposed solution is particularly suitable for nutrient recovery and environment pollution bioremediation, where energy harvesting is not requested.

Effects of Cathodic Process on Corrosion Fatigue of Type 316L Stainless Steel in 0.9 % NaCl Solution

Type 316L stainless steel exhibits superior corrosion resistance in aqueous environments, due to a protective passive film formed on the surface. Therefore, the stainless steel is used in diverse fields. However, during cyclic deformation of the steel in environments that contain chloride ions, the breakdown of the passive film on the steel surface occurs around stress concentration zones, causing the anodic dissolution of underlying steel. On the other locations, oxygen reduction reaction mainly occurs as cathodic reaction. Therefore, both anodic and cathodic reactions have to be taken into consideration to examine corrosion related phenomena. However, effects of cathodic reaction still remain unclear. In the present work, cyclic deformation test of Type 316L stainless steel with different cathode areas was performed to clarify effects of cathodic process on corrosion fatigue of the stainless steel.

Electrochemical Reduction of ZrO2 in Molten Electrolytes

The results of the electrochemical reduction of zirconium dioxide in molten electrolytes based on calcium or magnesium chloride on a liquid gallium cathode, bypassing the stage of granulation and sintering with carbohydrates, are presented. The liquid gallium cathode provides not only reliable contact with zirconium dioxide, but also favourable conditions for its reduction. The contact area of the gallium cathode with fine oxide powder is much larger than the contact area of the granulated and sintered zirconium dioxide with a solid conductor. This ensures a more uniform cathode polarization. Due to the lower specific mass, zirconium dioxide is located on the surface of gallium cathode, the convective movement of which provides more intense mass transfer at the interface of the phases and removal of recovery products from the zone of electrode reaction. Products of electrolysis under such conditions do not block neither the surface of zirconium dioxide nor the surface of the cathode. Zirconium, which is formed during the renewal, due to a larger specific mass, precipitates to the bottom of the electrolyser, and the layer of gallium protects it from interaction with the components of the molten electrolyte. In addition, due to the formation of alloys, the reduction of metal cations on liquid cathodes proceeds at more positive potentials than on solid indifferent cathodes, which reduces the specific energy consumption by electrolysis. The results of voltammetric studies confirm this conclusion.The reduction product is fine-grained zirconium powder with an average particle size of 1—3 microns, and purity of 99.9 %. As the density of the current increases, the value of the specific surface of the powder, the specific volume of the micropore and their average radius decrease. The degree of extraction depends on the composition of the electrolyte mixture and naturally decreases when replacing cations in the melts both on the basis of calcium chloride and on the basis of magnesium chloride in the following sequence Na+ > K+ > Li+. The melt based on compounds of calcium and sodium chloride provides the best performance. The removal degree of zirconium from such melt reaches 77 %.

Multidimensional Operando Analysis of Li/S Batteries with Neutrons and Photons

Lithium/sulfur (Li/S) batteries have a fivefold higher theoretical gravimetric energy density (2680 Wh/kg) than state-of-the-art lithium-ion batteries [1]. Furthermore, the abundance and environmental friendliness of sulfur qualify this system as a promising candidate for the post-lithium-ion era. However, the strong capacity fading with increasing cycle number is still a major obstacle to a broad technical utilization despite decades of research. Operando techniques [2] are very suitable tools to gain a mechanistic understanding of degradation processes. Especially the simultaneous combination of several independent measurements (multidimensional) while the Li/S cell is in operation allows deep insights into the degradation mechanisms and provides a further mechanistic understanding of the complex Li/S chemistry.Here we present results where up to five independent measurements are simultaneously performed with one setup (see image). Electrochemical impedance spectroscopy (EIS), UV-vis spectroscopy, temperature measurement, and X-ray imaging [3,4] or neutron small-angle scattering [5] were performed over several cycles while the cell was galvanostatically or potentiostatically charged and discharged. Structural changes on the macroscopic and microscopic scale can be correlated to characteristic signals in the EIS, charge-discharge curve, and UV-vis spectroscopy.The first part of the presentation focuses on X-ray imaging studies [3,4] that allow for valuable insights into operating Li/S cells. This method is a suitable tool for the investigation of the formation/dissolution processes of the charge product sulfur. The correlation of image analysis and impedance spectra enables a better mechanistic understanding of this system. Major observations are the formation of macroscopic alpha and beta-sulfur crystals, the formation of non-wetted cathode areas, and voltage-dependent electrolyte movement within the Li/S cell.The second part of the presentation deals with the formation and dissolution process of the discharge product, lithium sulfide. Here operando small-angle neutron scattering (SANS) is the weapon of choice to monitor nanoscopic lithium sulfide particles [5]. The SANS curves are correlated to the distribution of relaxation times calculated from impedance spectra. Furthermore, SANS gives information about the position of sulfur aggregation. In an ether-based electrolyte, neither lithium sulfide nor sulfur precipitate in the micropores.The last part of this presentation will give an outlook over the next experiments and discusses open questions in this field.

Analysis of the Impact of Fast Charging on Aging for Smartphone Cells: A Case Study Using Synchrotron Based Techniques

With the rapid market increase of consumer electronic devices such as smartphones and tablets, the performance of lithium-ion batteries (LIBs) in such devices becomes an important factor. In particular, fast charging, longer lasting batteries and safety are primary concerns for consumers. Lithium cobalt oxide (LCO) is a common cathode material for these applications, and in smartphone applications with 1-2 cycles a day, LCO has been proven to be a good cathode with its high cycle life.1,2 However, besides offering high cycling stability and power density for mobile consumer applications, another requirement for LIBs utilized in smartphones and other portable electronic devices is the capability of fast charging, without a detrimental impact on the cycling stability. Different fast charging profiles can lead to various extents of degradation within the full cell. Consequently, strategies are needed to avoid or mitigate any negative impact of fast charging on battery capacity, power degradation and cycle life.In this work, we employed extensive synchrotron-based characterization methods on smartphone batteries (LCO/graphite), offering new insight into the various degradation mechanisms during fast charging. Specifically we focus on an in-house developed fast-charging profile based on a physics-based battery model and compare it with the fast charging profile provided by the OEM. We reveal how lithium plating occurring on the anode side during fast charging is ‘mirrored’ on the cathode side leading to inactive cathode areas that only participate partly in lithium intercalation. While no morphological changes were observed in the cathode opposing the plating sides on the anode, in-situ hard XAS spectroscopy shows that deactivated spots on the cathode are not as redox active anymore, and synchrotron micro XRD shows significant changes in the lattice d-spacing value. We conclude that a fast charging strategy derived from a physics-based model drastically reduces capacity fade and rate of impedance rise in a LCO/graphite smartphone cell as used in this work. References 1 L. Wang, J. Ma, C. Wang, X. Yu, R. Liu, F. Jiang, X. Sun, A. Du, X. Zhou and G. Cui, Adv. Sci., 2019, 6,1900355.2 M. S. Whittingham, Chem. Rev., 2004, 104, 4271–4302.

Role of Martensite Structural Characteristics on Corrosion Features in Ni-Advanced Dual-Phase Low-Alloy Steels

The relationship between the corrosion resistance and martensite structure of Ni-advanced dual-phase weathering steel was studied using transmission electron microscopy, scanning electron microscopy, electrochemical analysis, and atomic force microscopy. The investigations indicate that the final microstructure of the dual-phase weathering steel was composed of a large amount of low-carbon lath martensite distributed in the ferrite matrix. The potential of the martensite phase is higher than that of ferrite, which acts as a microcathode. As the martensite volume fraction in the Ni-advanced dual-phase weathering steel increased, the corrosion rate increased owing to the greater galvanic couple formed between the ferrite and martensite from the increasing ratio of the cathode area to the anode area. In addition, this work provides a method to obtain advanced weathering steel with improved mechanical properties and corrosion resistance.

Revealing the growth kinetics of atmospheric corrosion pitting in aluminum via in situ microtomography

Understanding the mechanistic relationship between the environment, microstructure, and local kinetics of atmospheric corrosion damage remains a central challenge. To address this challenge, this study used laboratory-based X-ray tomography to directly observe attack in-operando over an extended period, enabling insights into the evolving growth kinetics and morphology of individual pits over months of exposure. Damage progression associated with nine pits in a 99.9% pure aluminum wire exposed to chloride salts in humid air was characterized. Most pits grew at a nominally linear rate up until pit death, which occurred within 12–24 h of nucleation. Exceptions to this were observed, with three pits exhibiting bimodal growth kinetics and growing for 40 or more hours. This was explained by secondary droplets that formed near the pits, increasing the cathode area. A corrosion-driven drying mechanism likely contributed to pit death in both cases. Pits first grew into the material followed by lateral expansion.

Experimental and theoretical study of new Schiff bases based on imidazo(1,2-a)pyridine as corrosion inhibitor of mild steel in 1M HCl

In this work, we report a study on the synthesis and characterization, using several spectroscopic techniques such as IR, 13C NMR, 1H NMR and mass spectroscopy, of a new series of Schiff bases based on imidazo(1,2a)pyridine (IMP) scaffold, and the evaluation of their ability to inhibit the corrosion of mild steel in 1M HCl by mass loss techniques, Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and quantum chemistry calculation based on density functional theory (DFT).The obtained results show that these inhibitors, namely (E)-N-(2-phenylimidazo(1,2-a)pyridin-3-yl)-1-(1H-pyrrol-2-yl)methanimine (IMP1), (E)-N-(2-phenylimidazo(1,2-a)pyridin-3-yl)-1-(thiophen-2-yl)methanimine (IMP2) and (E)-1-(5-nitrothiophen-2-yl)-N-(2-phenylimidazo(1,2-a)pyridin-3-yl)methanimine (IMP3), act only by reducing the cathode area without changing the mechanism of the cathodic reaction, and that the effectiveness of the inhibition increases with increasing concentration of the inhibitors. The adsorption of the studied compounds on the surface of mild steel follows the Langmuir isotherm model. And finally, we highlighted the existence of a correlation between the molecular structure of the tested inhibitors and their anticorrosion activity.

Electrokinetic remediation with solar powered for electrolytic manganese residue and researching on migration of ammonia nitrogen and manganese

With the development of manganese ore resources, a large number of electrolytic manganese residue (EMR) was produced, which causes serious environmental pollution (like water pollution, soil pollution, etc.). The control of water content and decomposition of compound salts are the key issues to harmless treatment of EMR. Among them, the control of ammonia nitrogen and manganese content and the decomposition of compound salts are the severe challenges facing the resource utilization of compound salt. Hence, from the perspective of environmental protection and energy-saving, this work adopted solar electrokinetic remediation methods to treat the EMR of an electrolytic manganese plant in Guangxi, then explores the changes of water content, pH value and NH4+-N and Mn2+ content in different regions of electrolytic cell. Besides, SEM, XRD and XRF were employed to analyze the basic physicochemical properties of the EMR before and after the remediation, from which it was found that under the action of an electric field, Mn2+ migrated directionally from the anode area to the cathode area and solidified into Mn(OH)2 and MnOOH. Meanwhile, NH4+-N migrated to the cathode, it formed (NH4)2SO4 on the surface of the EMR which can be easy to separate. After 72 h of solar electrokinetic remediation, the concentration of Mn2+ in the cathode area was decreased from 1725.5 mg L−1 to 84.3 mg L−1, and the NH4+-N content in the anode area declined from 907.9 mg L−1 to 196.4 mg L−1. In addition, (NH4)2(Mg, Mn, Fe)(SO4)2·6H2O and other compound salts can be decomposed into (NH4)2SO4 and (Mg, Mn, Fe)SO4, other single salts that can be cleaned easily under the action of the electric field.

Colorimetric aptasensor for fumonisin B1 detection by regulating the amount of bubbles in closed bipolar platform

A novel electrochromic biosensor has been developed by coupling the chemical sensing reactions at closed bipolar electrode (BPE) to the electrochemical reactions at the driving electrode for colorimetric detection of fumonisin B1 (FB1). Here, BPE is not only served as the sensing electrode, but also acted as a vital bridge to form electric connection between sensing and reporting solution. The conductive bridge was formed by connecting glassy carbon electrode (GCE) in sensing cell to Pt wire in reporting cell with electric wire. In order to achieve FB1 detection, a recognition probe was prepared by conjugating Au nanoparticles (NPs) labeled FB1 aptamer to capture DNA-Fe3O4 NPs surface. After the chemical reduction of silver ion on Au NPs, the prepared probes were introduced to GCE surface to catalyze the decomposition of H2O2 to oxygen bubbles by silver particles. The accumulation of numerous bubbles led to a significant decrement of the effective area of GCE cathode and current flow through the electric bridge which was reported by the inhibited electro-deposition of Prussian blue (PB) at ITO driving electrode in sensing cell. After adding FB1, Au NPs –aptamer was liberated from Fe3O4 NPs –capture DNA surface, resulting in a decreased amount of silver particles assembled on GCE and an increased amount of PB deposited at ITO electrode. This indirect colorimetric strategy provides a simple and portable for bioanalysis.

Nutrient Removal Process and Cathodic Microbial Community Composition in Integrated Vertical-Flow Constructed Wetland - Microbial Fuel Cells Filled With Different Substrates.

An integrated vertical-flow constructed wetland-microbial fuel cell system (CW-MFC), consisting of an up-flow chamber and a down-flow chamber, was constructed to treat synthetic sewage wastewater. The performance of CW-MFCs filled with different substrates [i.e., ceramsite (CM-A), quartz (CM-B), and zeolite (CM-C) granules] under various hydraulic retention times (HRTs, 7.6, 4.0, and 2.8 d) was evaluated. Efficient and stable nitrogen (N) and phosphorus (P) removals were observed in CM-A under different HRTs, while the voltage outputs of the CW-MFCs was greatly reduced as the HRTs decreased. With an HRT of 2.8 d, the ammonium (NH4+-N) and orthophosphate (PO43–-P) removal efficiencies in CM-A were as high as 93.8 and 99.6%, respectively. Bacterial community analysis indicates that the N removal in the cathode area of CM-A could potentially benefit from the appearance of nitrifying bacteria (e.g., Nitrosomonas and Nitrospira) and relatively high abundance of denitrifiers involved in simultaneous nitrification and denitrification (e.g., Hydrogenophaga, Zoogloea, and Dechloromonas) and denitrifying sulfide removal (e.g., Thauera). Additionally, the difference in N removal efficiency among the CW-MFCs could be partly explained by higher iron (Fe) content in milled ceramsite granules and higher abundance of denitrifiers with nitrate reduction and ferrous ions oxidation capabilities in CM-A compared with that in CM-B and CM-C. Efficient PO43–-P removal in CM-A was mainly ascribed to substrate adsorption and denitrifying phosphorus (P) removal. Concerning the substantial purification performance in CM-A, ceramsite granules could be used to improve the nutrient removal efficiency in integrated vertical-flow CW-MFC.

Advanced field emission measurement techniques for research on modern cold cathode materials and their applications for transmission-type x-ray sources.

We report on the functional capabilities of our field emission (FE) measurement systems. The samples are prepared and inserted under clean room conditions and can be precisely xyz-positioned, heat-treated, and investigated in different vacuum environments and temperatures. The FE scanning microscope is a unique microscope being used for the localization of FE sites with high lateral resolution by means of extraction voltage U(x, y) or emission current I(x, y) maps over the cathode area of 25 × 25 mm2 and measuring the FE properties of localized emission sites or individual emitters. In contrast, the integral measurement system with the luminescent screen provides real-time integral information about the distribution of emission sites over the whole cathode during long- and short-term current stability measurements, thus allowing us to investigate the properties of various materials and their applications. Commissioning results with the upgraded systems using a silicon emitter array and a point-type graphene emitter will be given to demonstrate that both FE measurement techniques are very useful for an improved understanding and tailoring of materials for applications. The results showed that point-type graphene emitters are more preferable for practical applications. Using simulation software, a suitable triode configuration for point emitters was designed, and a current transmission ratio of ∼100% was obtained. The FE current stability of graphene emitters at pressures >10-3 Pa can be improved by heating the cathode at 100 °C-300 °C for 1 min-30 min. Finally, point-type graphene film emitters were used for transmission-type x-ray sources, and their applications in imaging and fluorescence spectroscopy are presented.

Enhanced electrochemical degradation of 2,4-dichlorophenol with the assist of hydrochar

Effective treatment of 2,4-dichlorophenol (2,4-DCP) in wastewater is essential, as it could pose great threat to the environment. A hydrothermal biochar (hydrochar) was used to assist the electrochemical oxidation treatment of 2,4-DCP. The removal of 2,4-DCP using hydrochar in anode and cathode area with and without proton exchange membrane (PEM) under 3–9 V of electrolysis was investigated. Enhanced 2,4-DCP degradation in the anode area was achieved compared with the adsorption or electrolysis alone. The highest 2,4-DCP removal (∼76%) was obtained using the hydrochar in the anode area with PEM under 9 V. The mechanism for the 2,4-DCP removal during the electrolysis included adsorption by hydrochar and electrochemical degradation by the reactive oxygen species (ROS) generated by the electrode as well as the persistent free radicals (PFR) on hydrochar. The OH produced from anode was the predominant ROS contributing to the 2,4-DCP degradation under 9 V of electrolysis.

Preparation and characterization of La0.6Sr0.4Fe0.8Mn0.2O3-δ cathode of intermediate temperature solid oxide fuel cells

The aim of this study is to investigate the properties of the La0.6Sr0.4Fe0.8Mn0.2O3-δ (LSFM)compound as cathode of intermediate temperature solid oxide fuel cells. The LSFM compound was synthesized by the sol-gel process. Thestructural, electrical and electrochemical properties of LSFMwere tested via X-ray diffraction (XRD), scanning electron microscopy (SEM), high temperature four-probe resistivity measurement (HTRM) and electrochemical impedance spectroscopy (EIS). The X-ray pattern showed that sample had a Rhombohedra structure and space group symmetry of LSFM is R-3c; also, the LSFM had good chemical compatibility with YSZ electrolyte. The conductivity of the sample was increased with raising the temperature. The maximum electrical conductivities for the LSFM compound were equal to 3.64 S.cm-1 in air at 739 ℃. The cathode area specific resistance of LSFM was 1.69, 1.01, 0.63, 0.52, and 0.45 Ω cm2 at 600, 650, 700, 750, and 800 ℃, respectively

The influence of external and internal factors on stress corrosion cracking of low-alloyed pipe steel

The article presents investigation results of the regularities of stress corrosion cracking (SCC) of controllable rolling X70 pipeline steel under the influence of various factors: corrosion-active environment, potential, pre-accumulated stresses, periodic wetting, etc. Factors, acting in the conditions of the gas pipe mains operation, were simulated in the laboratory conditions and their influence on the SCC susceptibility of X70 pipe steel was investigated. It was found that in NS4 solution, potential shifting to the cathode area promotes the increasing of the SCC susceptibility of X70 steel. Under cathodic protection at potential equal to -1.0 V, the fracture characteristics change, a brittle component appears in the fracture, and the coefficient KS increases compared to the breaking of samples without cathodic potential. Under such a potential there may appear some differences in the SCC susceptibility of X70 steel, which have a minor structural features: steel with less contamination of non-metallic inclusions is less susceptible to brittle cracking. Accumulated cyclic stresses, periodic wetting, the presence of coatings with different transient resistance and the stress concentrator promote the increase of the degree of SCC susceptibility of X70 pipeline steel at a potential of -1.0 V.