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To accommodate the high-frequency and low-frequency power fluctuations of renewable energy generation with a lower system cost, a multi-electrolyzer hybrid hydrogen production system demonstrated potential for application. This study achieved the integration of proton exchange membrane electrolyzers and alkaline electrolyzers through hybrid control in a photovoltaic (PV)- transformer-electrolyzer coupled system for the first time, enabling the pre-regulation of the electrolyzer power based on the LSTM forecast of the power generation of PV, to avoid the impact of sudden large power fluctuations on the electrolyzers, with a lower system cost and higher production rate. Experiment results indicate that this hybrid hydrogen production system reduces system initial investment cost by 27.2% compared to a pure PEMWE system and increases hydrogen production by 58.7% compared to a pure AWE system. • A new hybrid hydrogen production system is proposed. • Coupling of power electronic devices and multiple electrolyzers is simulated. • A high-efficiency and low-cost hydrogen production system adaptable to power fluctuations is established. • Power pre-regulation for multiple electrolyzers based on PV power prediction is established. [ABSTRACT FROM AUTHOR]

In both the manufacturing and chemical industries, benzoquinone is a crucial chemical product. A perfect and economical method for making benzoquinone is the electrochemical oxidation of phenol, thanks to the traditional thermal catalytic oxidation of phenol process requires high cost, serious pollution and harsh reaction conditions. Here, a unique heterostructure electrocatalyst on nickel foam (NF) consisting of nickel sulfide and nickel oxide (Ni9S8‐Ni15O16/NF) was produced, and this catalyst exhibited a low overpotential (1.35 V vs. RHE) and prominent selectivity (99 %) for electrochemical phenol oxidation reaction (EOP). Ni9S8‐Ni15O16/NF is beneficial for lowering the reaction energy barrier and boosting reactivity in the EOP process according to density functional theory (DFT) calculations. Additionally, an alkali/acid hybrid flow cell was successfully established by connecting Ni9S8‐Ni15O16/NF and commercial RuIr/Ti in series to catalyze phenol oxidation in an alkaline medium and hydrogen evolution in an acid medium, respectively. A cell voltage of only 0.60 V was applied to produce a current density of 10 mA cm−2. Meanwhile, the system continued to operate at 0.90 V for 12 days, showing remarkable long‐term stability. The unique configuration of the acid‐base hybrid flow cell electrolyzer provides valuable guidance for the efficient and environmentally friendly electrooxidation of phenol to benzoquinone. [ABSTRACT FROM AUTHOR]

The electrochemical synthesis of sodium ferrate for water purification is a promising solution to the problem of clean water. The materials and methods required for the process are considered. Particular attention is paid to the material and technology of obtaining an electrolytic cell that ensures stable and safe production of sodium ferrate. Different recirculation rates and their influence on the final product are considered. [ABSTRACT FROM AUTHOR]

This study introduces a quantitative evaluation method for the lifecycle of electric hydrogen production in microgrids, considering line electric thermal couplers. By analyzing the operational mechanism and benefits of hydrogen production through residual electricity, we systematically evaluated the cost‐effectiveness of Proton Exchange Membrane electrolytic hydrogen production. A comprehensive lifecycle cost model was constructed, including equipment investment, maintenance, operating costs, and line thermocouple failure costs. By combining hydrogen sales, electricity consumption, new energy subsidies, and delayed construction benefits, a lifecycle benefit model was developed to measure economic performance. Experimental results showed that under a 5% power outage rate, the hydrogen distribution network has a short investment payback period, high production, and significant economic benefits, reaching 23.19 million US dollars by the sixth year. This study provides valuable insights for economic decision‐making in electric hydrogen microgrids. [ABSTRACT FROM AUTHOR]

The feasibility of hydrogen production using cheese whey wastewater (CWW) in an electrolytic process is investigated. The experimental setup consists of a two-compartment electrolytic cell. Different conditions are evaluated, including several electrode materials, variable pH values, and the type of cell membrane. The optimal conditions involve a 316 stainless-steel anode, nickel foam as the cathode, an anion-exchange membrane, and CWW in both the anolyte and catholyte. It was demonstrated that when using CWW as the electrolyte in the anodic chamber or simultaneously as anolyte and catholyte, it is possible to electrolytically generate hydrogen at voltages below the theoretical value required for water splitting. A maximum hydrogen productivity of 9.78 ± 0.45 L H 2 /L-d was achieved (at 0.51 V), and the energy consumption is only 12.15 kWh/kg H 2. These results show that the electrolytic process produces significantly more hydrogen than the biological fermentative process. • H 2 was electrochemically produced from fermented cheese whey wastewater (CWW). • A maximum hydrogen productivity of 9.8 L H 2 /L-d was achieved. • Metal oxidation reactions from the anode replace the water oxidation in the anolyte. • Low energy consumption in the electrolytic H 2 production process was observed. • Carboxylic acids in the fermented CWW boost the H 2 production in the catholyte. [ABSTRACT FROM AUTHOR]

Copyright of Low-Carbon Chemistry & Chemical Engineering is the property of Low-Carbon Chemistry & Chemical Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sodium hypochlorite (NaClO) is used on a large scale for water disinfection, fabric bleaching, and odor removal. It is preferred due to the environmental risk of liquid chlorine associated with storage and transport. The objective of the research was the electrochemical generation of sodium hypochlorite from an aqueous solution of sodium chloride. Different operating conditions affecting the sodium hypochlorite generation process were studied, including electrical potential (6 and 10 V), sodium chloride concentration (80 and 120 g/L), and electrolysis time (30 and 60 minutes. To analyze the effect of the factors with respect to the response variable such as sodium hypochlorite concentration and energy consumption per kilogram of hypochlorite produced, a two-level factorial design was used for each factor. The best operating conditions produced when the applied electric potential was 10 V, sodium chloride concentration 120 g/L, and treatment time of 60 minutes reaching a concentration of 2276 g/L NaClO and a free chlorine percentage of 0.23 %. As well, the energy consumption per kilogram of hypochlorite is in the range of 3.31 and 11.78 kWh/kg. [ABSTRACT FROM AUTHOR]

The results of work on the creation of an efficient and economical method, as well as the manufacture and testing of an installation for non-destructive quality control of baked anodes of aluminum electrolytic cells. The installation uses the method of measuring the electrical resistance of the anode and building its calculation model with known data on its geometry and resistivity, as well as the geometry and coordinates of internal defects. In this case, a series of calculations is performed to obtain a 3D matrix of amplitudes and directions of the vectors of the calculated strengths or inductions of the electromagnetic field at points located near the outer surface of the anode. To do this, at least two electrically conductive contacts are placed at these points, passing a given amount of electric current through the anode. Also, at least one sensor is placed near the outer surface of the anode and the amplitude and direction of the magnetic field intensity or induction vectors are measured and displayed in the form of a 3D matrix of the measured intensity or magnetic field induction vectors. After that, the 3D matrices of the calculated and measured vectors of the strength or induction of the magnetic field are compared at the same points located near the outer surface of the anode and, based on these results, the sizes and coordinates of internal defects are determined. The technical result of the implementation of the proposed method is to increase the accuracy, reliability and reliability of determining the location of defects in baked anodes. The installation was tested in laboratory and industrial conditions, which showed good agreement between the results obtained and the data obtained by destructive testing. The entire procedure for checking the quality of one anode took 45–50 s. As a result of preliminary tests, it was determined that out of 100% of the anodes approved for use by the manufacturer, 13.5% were rejected by NDF testing. During research in the Siberian Federal University laboratory, it was found that the accuracy of detecting defective anode blocks using NDF was 82%. Industrial test results of the installation made it possible to divide all anode blocks into 4 classes based on quality, and the validity of this division was confirmed by destructive testing tests. [ABSTRACT FROM AUTHOR]

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A study was made of the component of the error in measuring the resistance of an electrolytic cell with a solution, which is due to the shunting effect of the thermostat liquid. A physical model and equivalent circuits for a cell placed in a thermostat are proposed. The model is based on the example of a two-electrode cell of a common design, which is used for secondary standards of electrolytic conductivity (for solutions with low electrolytic conductivity). For research, computer simulation in the COMSOL Multiphysics software environment was used. The calculated values ​​of the immittance components of computer models of the cell were obtained in the software environment as a result of solving field tasks using the finite element method. The results of the work showed that the values of the investigated component of the relative error can exceed 0.1 % in real measurements of the electrolytic conductivity of solutions using cells of the considered type. [ABSTRACT FROM AUTHOR]

In this paper, a new electrolysis device was presented with corundum crucible as an electrolytic cell in place of a graphite crucible, and in the corundum crucible a sleeve with a cathode pellet with a fluted base placed flat in it was adopted to separate the cathode and anode. The process of electrochemical reduction of solid TiO2 to Ti in situ was studied and characterized by the time–current curves and X-ray diffraction (XRD) patterns of the electrochemical reduction products. The influence of CaCl2 doping in the cathode and the electrolysis device structures on electrochemical reduction mechanisms and the process strengthening was systematically studied. The results show that the oxygen content in the obtained Ti is reduced to 0.51% with a cathode pellet sintering temperature of 1000 °C, sample preparation pressure of 20 MPa and CaCl2 doping amount of 30%. Tiny holes are formed in the cathode pellet by CaCl2 doping in the electrochemical reduction process, which could increase the contact area between the electrolyte and cathode and improve the electrode reaction efficiency. The new electrolysis device could reduce the carbon content in the molten salt, cathode polarization and the electrode reaction overvoltage, inhibit the chances of secondary reactions, increase the contact area between the produced Ca and cathode and strengthen the thermal reduction of TiO2 by Ca. [ABSTRACT FROM AUTHOR]

Against issues of the high overpotential, low conversion efficiency, and poor product selectivity of electrochemical CO2 reduction (CO2ER), the research progress of electrocatalysts, electrolytes, and electrolytic cells were reviewed. It was found that the currently developed electrocatalysts contained metal nanoparticles, metal alloy, metal oxides, metal sulfide and single metal atoms. Their catalytic activity, selectivity and stability could be enhanced by adjusting the structure and particle size of electrocatalysts, doping additional elements or introducing structural defects. The electrolyte of CO2ER included aqueous electrolyte, ionic liquid electrolyte and organic electrolyte. At present, the aqueous electrolyte was widely applied, but its selectivity was inhibited by the side hydro- gen evolution reaction. The ionic liquid electrolyte and organic electrolyte has high solubility of CO2 and could restrain the hydrogen evolution reaction, which was considered as the main application research direction in the future. The CO2ER can be conducted in H-type cell, continuous flow cell and MEA reactors, among which MEA is one of the important technology to realize the scale application of electrochemical CO2 conversion. In the future, the reaction mechanism should be further studied, and the active sites should be probed to realize the precise control of catalytic performance and stability. Meanwhile, the novel electrolytes should be developed and the design of electrolytic cell should be modified in order to further improve the catalytic performance. [ABSTRACT FROM AUTHOR]

Copyright of Hydrometallurgy of China is the property of Hydrometallurgy of China Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The current experimental study looks at how the limiting current density is approached on using rotating 2-stage 4- blade flat turbine promoters to improve mass transfer coefficient in an open electrolytic cell. The mass transfer data are obtained at microelectrodes fixed on the cell wall and electrode support using an electrochemical method. The electrolyte was equimolal in potassium ferricyanide, potassium ferrocyanide and excess sodium hydroxide. The mass transfer coefficients were calculated using limiting current data from a diffusion-mediated electrode reduction reaction at the microelectrodes attached to the electrode supports. The limiting current technique has been particularly chosen in view of its accuracy, simplicity, negligible chemical polarization, and absence of any physical change to the reacting surface even after long exposure. The effects of geometric parameters such as turbine diameter (0.05-0.09 m), blade width (0.005-0.015m), turbine rotational speeds (250-1250 rpm) and electrolyte velocity (0.567x10-3 to 7.93x10-3 m/s) were investigated. The mass transfer coefficients were increased by the turbulence created by rotation of the promoter turbines. The mass transfer correlation was formed in terms of dimensionless numbers: Schmidt number (Sc), Sherwood number (She), rotational Reynolds number (Rer), and flow Reynolds number (Ref).

A three‐dimensional (3D) model simulating the flow, heat, and mass transfer characteristics of a high‐temperature solid oxide electrolytic cell (SOEC) is developed based on the coupling of gas flow in channels, the electrochemical reaction in the triple‐phase boundary of electrodes and component diffusion in the porous media in electrodes. The model comprises several equations such as mass equation, momentum equation, energy equation, mass transport equation, and electrochemical reaction equation. The computational fluid dynamics method is adopted to simulate the operating performance (current density distribution, temperature distribution, and gas component distribution) of the 3D electrolytic cell model under different operating conditions (electrolytic voltage, gas temperature at the inlet, flow rate and flow pattern). The simulation results show that gas temperature at the inlet obviously influences electrolytic hydrogen production by SOEC. In the case of lower voltage, a higher temperature can be selected to effectively increase the current density. When the current density is high enough, the supply flow of water vapor needs to be increased to prevent the inhibition reaction of low‐concentration reactants, but this may lead to the reduction of water vapor conversion. In practical operation, a lower voltage and higher gas temperature should be selected, and the flow rate of water vapor appropriately increased to ensure hydrogen production and improve operating efficiency. [ABSTRACT FROM AUTHOR]

The gas purging states affect electricity output and energy storage capacity of unitized regenerative fuel cells. In this study, a model of unitized regenerative fuel cell is established. Cell voltages and operating temperatures influences on the dynamic distribution of thermal fluid during purging process and the discharge of residual liquid water in electrolytic cell mode are investigated. The motivation of the present study is better understanding the gas purging characteristics and its effect on reaction behaviors of unitized regenerative fuel cells. Simulation results reveal a significant influence of purging gas temperature on the water flooding and a great effect of operating voltage on the water diffusion. The operating temperature of electrolytic cell model almost has little effect on purging results at different cell temperature and the same purging gas temperature. When the purging gas temperature is changed, higher temperatures of cell and purging gas facilitate liquid water discharging out from the cell regions. In cell water flooding situation, when having large liquid content, the purging gas has little effects on the water expelling process. • EC temperature exhibits obscure effect on water transportation under same purging temperature. • Higher cell temperature and purging temperature facilitate expelling water from the cell. • Purging temperature hardly affects water expelling during the cell flooding processes. • Liquid water remaining in CLs is less under higher cell voltage conditions. [ABSTRACT FROM AUTHOR]

The development of technology for obtaining large-sized steel-copper cathodes applied in aluminum electrolytic cells is considered. The developed approach is based on diffusion welding through the nickel layer using low-tech industrial equipment. During experiments on obtaining the fragments of steel-copper cathodes with natural cross-sectional dimensions, St3 steel, M1 copper, and NP2 nickel were used. The dimensions of the steel and copper workpieces were 115 × 230 and 12 × 150 mm in the cross-section with a length of 470 and 460 mm, respectively. Nickel workpieces were made as 0.5 mm thick sheets with plan dimensions of 150 × 460 mm. The proposed technology for obtaining actual-sized steel-copper cathodes according to the experimental results includes the supply of a three-layer pack having a length of 2000 mm to the hydraulic press table and its compression with subsequent welding. In order to implement the described technology, the pressing force should ensure the transition of copper and nickel in the compressed section into a plastic state. The dimensions of the furnace working chamber are applicable to the placement of the pack and its heating to a temperature of 980 ± 20°C. [ABSTRACT FROM AUTHOR]

The current distribution in a fresh aluminum electrolytic cell with slotted carbons is investigated by the Finite Element Method (FEM). The effects of the length of slots, la and lc on current distribution were also determined. The maximum local current density and its position do not change with an increase in lc (0 ≤ lc ≤ 200 mm) for a 400 mm slot located 150 mm from the upper surface of the cathode carbon. However, the maximum current density shifts towards the cell center with increasing slot lengths. Current distribution control thus plays a role in optimizing the cathode slot length. [ABSTRACT FROM AUTHOR]

In both the manufacturing and chemical industries, benzoquinone is a crucial chemical product. A perfect and economical method for making benzoquinone is the electrochemical oxidation of phenol, thanks to the traditional thermal catalytic oxidation of phenol process requires high cost, serious pollution and harsh reaction conditions. Here, a unique heterostructure electrocatalyst on nickel foam (NF) consisting of nickel sulfide and nickel oxide (Ni 9 S 8 -Ni 15 O 16 /NF) was produced, and this catalyst exhibited a low overpotential (1.35 V vs. RHE) and prominent selectivity (99 %) for electrochemical phenol oxidation reaction (EOP). Ni 9 S 8 -Ni 15 O 16 /NF is beneficial for lowering the reaction energy barrier and boosting reactivity in the EOP process according to density functional theory (DFT) calculations. Additionally, an alkali/acid hybrid flow cell was successfully established by connecting Ni 9 S 8 -Ni 15 O 16 /NF and commercial RuIr/Ti in series to catalyze phenol oxidation in an alkaline medium and hydrogen evolution in an acid medium, respectively. A cell voltage of only 0.60 V was applied to produce a current density of 10 mA cm -2 . Meanwhile, the system continued to operate at 0.90 V for 12 days, showing remarkable long-term stability. The unique configuration of the acid-base hybrid flow cell electrolyzer provides valuable guidance for the efficient and environmentally friendly electrooxidation of phenol to benzoquinone., (© 2024 Wiley-VCH GmbH.)

The present study aimed to evaluate the factors that influence the formation of sodium hydroxide (NaOH) by means of an electrolytic cell with ion exchange membranes. To achieve this experiment, the NaOH production cell had to be designed and built inexpensively, using graphite electrodes. The operational parameters in our study were: initial NaOH concentration, applied voltage, and temperature. All experiments were carried out using model NaCl solutions with a concentration of 40 g/L for 150 min. The results of the experiment were that the NaOH concentration, conductivity, and pH presented an increasing linear trend with the electrolysis time. Finally, it was possible to obtain the efficiency level of the electric current in our investigation, which was an average of 80.2%, that indicated good performance of the built cell. [ABSTRACT FROM AUTHOR]

The production of succinic acid from fermentation is a promising approach for obtaining building-block chemicals from renewable sources. However, the limited bio-succinic yield from fermentation and the complexity of purification has been making the bio-succinic acid production not competitive with petroleum-based succinic acid. Membrane electrolysis has been identified to be a promising technology in both production and separation stages of fermentation processes. This work focuses on identifying the key operational parameters affecting the performance of the electrolytic cell for separating succinic acid from fermentation broth through an anionic exchange membrane. Indeed, while efforts are mainly focused on studying the performance of an integrated fermenter-electrolytic cell system, a lack of understanding remains in how to tune the electrolytic cell and which main parameters are involved. The results show that a single electrolytic cell of operating volume 250 mL was able to extract up to 3 g L−1 h−1 of succinic acid. The production of OH− ions by water electrolysis can act as a buffer for the fermenter and it could be tuned as a function of the extraction rate. Furthermore, as the complexity of the solution in terms of the quantity and composition of the ions increased, the energy required for the separation process decreased.

Mesoporous cobalt oxide/nickel foam (NF) is got by a simple chemical method, and a glycerin-based electrolytic cell is rationally assembled with CoO/NF, in which glycerin-KOH aqueous solution is used as electrolyte. Herein, the influence of anodic glycerin oxidation on cathodic hydrogen production is investigated mainly. At 1.35 V vs. reverse hydrogen electrode (RHE), CoO/NF electrode exhibits a current density of 235.71 mA cm−2 for glycerin oxidation, which is about 2.5 times higher than that over Co 3 O 4 /NF. For glycerin oxidation, the Tafel slope (189 mV dec−1) over CoO/NF is much lower, compared to that (286 mV dec−1) over Co 3 O 4 /NF, demonstrating the robust electrocatalyic reaction kinetics over CoO/NF. For glycerin-contained electrolytic cell, a cell voltage (1.672 V) is needed to reach 50 mA cm−2, which is obviously lower than that (1.975 V) for conventional electrolytic cell. It is obvious that for glycerin-contained electrolytic cell, the required cell voltage has obviously decreased by 0.303 V. This work demonstrates that the substitution of glycerin oxidation for sluggish four-electron OER reaction can greatly promote water electrolysis to hydrogen production. Moreover, this design can not only degrade environmental pollutants, but also produce clean energy, and the reported strategy is obviously environment-benign and cost-effective. Image 1 • Electrolytic cells are assembled with glycerin. • Cell voltage is 0.303 V lower than conventional one at 50 mAcm−2. • The HER potential with glycerin is lower than that without glycerin. • The design can not only degrade pollutants, also produce clean energy. [ABSTRACT FROM AUTHOR]

In order to improve the electrolysis efficiency of lithium metal electrolysis cell, the multi physical simulation software was used to simulate the three dimensional heat field of lithium metal electrolysis cell under different voltages and different external auxiliary heat temperatures based on 600 A lithium electrolysis cell. And combined with the experimental analysis- The results show that on the same level,the higher temperature area of the electrolytic cell is between the anode and cathode, the anode surface temperature is higher than the cathode. The closer to the anode, the higher the molten salt electrolyte temperature is- When the DC voltage is 5. 5 V and the external auxiliary heat temperature is 370 °C, the thermal field distribution is reasonable and the electrolytic efficiency is relatively high, which provides a reference for the structure optimization of this electrolytic cell. [ABSTRACT FROM AUTHOR]

The excessive enrichment of nitrate in the environment can be converted into ammonia (NH 3 ) through electrochemical processes, offering significant implications for modern agriculture and the potential to reduce the burden of the Haber-Bosch (HB) process while achieving environmentally friendly NH 3 production. Emerging research on electrocatalytic nitrate reduction (eNitRR) to NH 3 has gained considerable momentum in recent years for efficient NH 3 synthesis. However, existing reviews on nitrate reduction have primarily focused on limited aspects, often lacking a comprehensive summary of catalysts, reaction systems, reaction mechanisms, and detection methods employed in nitrate reduction. This review aims to provide a timely and comprehensive analysis of the eNitRR field by integrating existing research progress and identifying current challenges. This review offers a comprehensive overview of the research progress achieved using various materials in electrochemical nitrate reduction, elucidates the underlying theoretical mechanism behind eNitRR, and discusses effective strategies based on numerous case studies to enhance the electrochemical reduction from NO 3 - to NH 3 . Finally, this review discusses challenges and development prospects in the eNitRR field with an aim to guide design and development of large-scale sustainable nitrate reduction electrocatalysts., (© 2024 Wiley‐VCH GmbH.)

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The results of exploring the prospects of hydrogen economy are presented. The complete production chains are investigated considering various technologies of production, storage, and subsequent utilization of hydrogen in transportation and electric power generation. Comparative analysis of the economic competitiveness of these chains with each other and with solutions based on the use of alternative fuels has been performed. Potential segments for the commercial application of the technologies and the conditions required have been evaluated. The analysis has established the most promising directions in the development of hydrogen economy. They primarily include the use of hydrogen in the defense industry and power supply of critical facilities, where the energy generation costs are not a determining factor. To be competitive in the civil consumption sectors, such as transportation and the power industry, hydrogen technologies have to become significantly less expensive or to receive the corresponding regulatory support. In many countries, the environmental sustainability of hydrogen production will have great significance. The authors conclude that hydrogen can become one of the fuels of the future; to effect this, however, we will have to tread a difficult path of technological progress under stiff competition with continuously developing alternative power-generation methods. [ABSTRACT FROM AUTHOR]

• A critical review on the influence of reactor design for electrochemical CO 2 reduction. • The feature, advantage and disadvantage of all types of electrolytic cells are compared. • H-type cell, flow cell and DEMS cell are emphasized with good potentials. • Perspectives and challenges for electrochemical cells are discussed. Transmute CO 2 to value-added chemical products by electrochemical reduction is a potential candidate and a highly providential route to mitigate CO 2 levels in atmosphere and meet the energy and global warming crisis. Recent reported studies have focused on advancement of novel electro-catalysts with outstanding performance, but unfortunately, little attention has been paid to the influence of reactor design. In this contribution, we for the first time comprehensively review all types of electrolytic cells reported in literatures and compare their features, advantages and disadvantages for CO 2 electro-reduction. To date, H-type cell is still the well-known typical reactor for CO 2 RR, typically for screening electro-catalysts. Based on H-type cell, a similar modified sandwich-type cell is designed to reduce system resistance. However, for industrialization, the flow cell in which the reactants and products are continuously transferred to and away from the electrodes, need further advancement because of its efficient mass transfer efficiency. Besides, the DEMS cell is an effective way to detect products efficiently in real time and analyze reaction process, which is useful for seeking reaction mechanism. The perspectives and challenges for the development of electrochemical cells are also addressed. We hopeful, this review should provide researchers with a clearer understanding of reactor selection, and impart important, timely and valuable insights into the design of advance electrolytic cells and its practical applications for CO 2 reduction. [ABSTRACT FROM AUTHOR]

• Carbon dioxide reduction in a microfluidic electrochemical cell is modeled. • Gradient or double-layers porosity in the gas diffusion electrode is investigated in. • The effects of porosity on fluid flow, diffusion and reaction sites are considered. • Optimized porosity has greater current density and Faraday efficiency. • Structural variation in the cell is investigated under different operating conditions. To obtain better electrical behavior, the linear or double-layers porous electrode is set in microfluidic electrochemical cell for CO 2 diffusion, which couples Tafel's law and Ohm's law with the flow equation and species transport equation for numerical calculations. This research analyzes the effects of linear or double-layer porosity, the thickness of double-layer porosity, and electrode structure in the electrode on current density, CO 2 conversion, and Faraday efficiency under different working conditions. The higher current density and CO 2 conversion occur in the case with smaller porosity in the electrode due to more reactive sites, and poor gas transport is observed simultaneously. Optimizing linear or double-layers porosity distribution results in higher current density, CO 2 conversion, and Faraday efficiency. The Faraday efficiency can reach 91.54% in the case of stepwise increasing porosity from 0.3 to 0.9 in the electrode. Poor electrical behavior occurs as linear increasing porosity compared to stepwise porosity due to different porosity distributions, and the opposite is the case for decreasing linear porosity. Setting the double-layer porosity along the electrode thickness direction results in larger Faraday efficiency as a thickness ratio of 1:1 and larger current density and CO 2 conversion as a thickness ratio of 4:1 in the case of porosity from 0.3 to 0.9. Better electrochemical behavior occurs with electrode thickness to length ratio of 10–20 and the CO 2 gas channel to electrode thickness ratio of 1:1–4:1, and optimized electrode porosities tend to show higher Faraday efficiencies during electrode structural changes. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the factors that influence the formation of sodium hydroxide (NaOH) by means of an electrolytic cell with ion exchange membranes. To achieve this experiment, the NaOH production cell had to be designed and built inexpensively, using graphite electrodes. The operational parameters in our study were: initial NaOH concentration, applied voltage, and temperature. All experiments were carried out using model NaCl solutions with a concentration of 40 g/L for 150 min. The results of the experiment were that the NaOH concentration, conductivity, and pH presented an increasing linear trend with the electrolysis time. Finally, it was possible to obtain the efficiency level of the electric current in our investigation, which was an average of 80.2%, that indicated good performance of the built cell.

Three types of antimony and bismuth electrolytic cells to be used for lead electrorefining were developed and tested. The electrolytic cell with the bipolar metallic electrode, the electrolytic cell with two anodes and one cathode, and the electrolytic cell with the porous diaphragm were studied. The tests demonstrated that lead is effectively separated from the metallic impurities in all constructions. Grade lead may be obtained at the cathode, and lead-antimony and lead-bismuth alloys may be produced at the anode. The electrolytic cell with a porous diaphragm was found to double the production rate and greatly decrease the electrical potential of the cell as compared to the other two constructions.

• A two-phase simulation in a unitized regenerative fuel cell is performed. • Relative humidity effect on purging is studied under severe water flooding condition. • Purging result shows diverse effects on cell start-up performance in fuel cell mode. A unitized regenerative fuel cell is a typical gas–liquid two-phase system that consumes oxygen and hydrogen in a fuel cell mode and liquid water in an electrolytic cell mode. Liquid water removal is crucial for a successful cell start-up after the electrolytic cell mode ends. However, investigations on two-phase transfer mechanisms for liquid water removal are limited during mode switching. To fill this research gap, a three-dimensional two-phase full-cell model is developed to describe charges, gas mixtures and liquid water transfer corresponding to operational modes of electrolytic cell, gas purging and fuel cell. The cell is assumed to being in the isothermal state. Numerical model is analyzed by using COMSOL Multiphysics 5.3a software. Furthermore, experimental and simulated results are compared to validate the proposed model. Results show that more than 84.0% of pore volume is occupied with liquid water on porous layers in an electrolytic cell mode. Although pre-switching for water removal can decrease the volume fraction of liquid water within the porous layers from 0.88 to 0.50 in a short time, more time is required for liquid water being carried away under a low level of water flooding. Purging result presents diverse influences on start-up performance in a fuel cell mode. Liquid water distribution, which is similar to that in a fuel cell mode, formed in a purging mode is encouraged for promoting a quick and stable start-up in a fuel cell mode. [ABSTRACT FROM AUTHOR]

Hydrogen production from the sulfur–iodine water splitting cycle integrated with solar or nuclear energy has been proposed as a promising technique. Bunsen reaction is one of the three main steps in the cycle and electrochemical method has been applied to this reaction. In present work, a three-dimensional numerical study of the electrochemical Bunsen reaction was conducted. A three-dimensional, steady state, laminar and isothermal mathematical model of electrolytic cell was developed and verified by experiments. The spatial maldistribution of species concentration was found between electrodes and proton exchange membrane (PEM). The electric power drives most H 2 SO 4 and I 2 to the anode and cathode surface, respectively, while the proton attraction contributes to HI enrichment on the surface of PEM. At the high inlet H 2 SO 4 concentration of 50 wt%, the transformation of flow channel from single serpentine to single entry & double serpentine with the same inlet flow rate cannot solve the insufficient problem of SO 2. But the increase of the overall inlet flow rate in the double entry & double serpentine flow channel make SO 2 sufficient for anode reaction. Further decreasing the inlet H 2 SO 4 concentration to 40 wt% and 30 wt% make the initial SO 2 sufficient for overall reactions. The single serpentine channel gives the highest SO 2 conversion rate, followed by the single entry & double serpentine and double entry & double serpentine flow channels. The single serpentine flow channel at the H 2 SO 4 inlet concentration of 40 wt% is found optimal for achieving a high electrochemical Bunsen reaction performance. • Three-dimensional study of electrochemical Bunsen reaction was first conducted. • A 3-D, steady state, laminar and isothermal model of EC was developed. • Transformation of flow channel and key initial conditions were analyzed. • Single serpentine flow channel at inlet H 2 SO 4 of 40 wt% was optimal. [ABSTRACT FROM AUTHOR]

Algebraic hyperstructures represent a natural extension of classical algebraic structures and they have many applications in various sciences. The main purpose of this paper is to provide a new application of n-ary weak hyperstructures in Chemistry. More precisely, we present three different examples of ternary hyperstructures associated with electrochemical cells. In which we prove that our defined hyperstructures are ternary Hv-semigroups. [ABSTRACT FROM AUTHOR]