Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
4.7
3.5
Journals
Processes
Special Issues
Electrolysis Processes
share announcement

Electrolysis Processes

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Chemical Processes and Systems".

Deadline for manuscript submissions: closed (30 November 2019) | Viewed by 125736

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editor

Dr. Tanja Vidakovic-Koch

E-Mail Website
Guest Editor
Electrochemical Energy Conversion (EEC), Max Planck Institute for Dynamics of Complex Technical Systems Sandtorstraße 1, D-39106 Magdeburg, Germany
Interests: dynamics of electrochemical systems; electrolysis; low temperature fuel cells; electroenzymatic processes; energy conversion in synthetic biology

Special Issue Information

Dear Colleagues,

Renewable energies such as solar, hydro or wind power are in principal abundant but subjected to strong fluctuations. Therefore, the development of new technologies for the storage of these renewable energies is of special interest. One scenario in energy storage is the chemical transformation of chemical compounds, such as water or carbon dioxide, into energy sources such as hydrogen or alcohols. Because of the rapid dynamics of electrochemical processes, it can be surmised that there will be an increased electrification of chemical processes for the use of excess current. In addition to the above-mentioned processes (water and CO2 electrolysis), the chemical industry, in the transition from fossil to renewable resources, requires new processes based on renewable raw materials. Here too, electrochemical and especially bio-electrochemical processes offer an attractive solution. This Special Issue of Processes invites contributions covering all electrochemical technologies supporting the transition from fossil to renewable energies and/or raw materials. Our special focus is on water and CO2 electrolysis. We encourage further contributions on novel electroenzymatic and microbial processes. Both experimental and modeling works providing new insights into the operation of electrochemical reactors under dynamic conditions, including aspects of catalyst and component aging (membranes, current collectors), as well as productivity and selectivity issues are highly welcome. The contributions can be regular papers, reviews or mini-reviews.

Dr. Tanja Vidakovic-Koch
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • water electrolysis
  • CO2 electrolysis
  • electroenzymatic processes
  • microbial processes
  • dynamic operation
  • catalyst aging
  • selectivity and productivity

Published Papers (11 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Editorial

Jump to: Research, Review

4 pages, 157 KiB  
Editorial
Editorial on Special Issue Electrolysis Processes
by Tanja Vidaković-Koch
Processes 2020, 8(5), 578; https://doi.org/10.3390/pr8050578 - 14 May 2020
Cited by 3 | Viewed by 1857
Abstract
Renewable energies such as solar, hydro or wind power are in principal abundant but subjected to strong fluctuations [...] Full article
(This article belongs to the Special Issue Electrolysis Processes)

Research

Jump to: Editorial, Review

10 pages, 2676 KiB  
Article
A Novel Porous Ni, Ce-Doped PbO2 Electrode for Efficient Treatment of Chloride Ion in Wastewater
by Sheng Liu, Lin Gui, Ruichao Peng and Ping Yu
Processes 2020, 8(4), 466; https://doi.org/10.3390/pr8040466 - 16 Apr 2020
Cited by 16 | Viewed by 2914
Abstract
The porous Ti/Sb-SnO2/Ni-Ce-PbO2 electrode was prepared by using a porous Ti plate as a substrate, an Sb-doped SnO2 as an intermediate, and a PbO2 doped with Ni and Ce as an active layer. The surface morphology and crystal [...] Read more.
The porous Ti/Sb-SnO2/Ni-Ce-PbO2 electrode was prepared by using a porous Ti plate as a substrate, an Sb-doped SnO2 as an intermediate, and a PbO2 doped with Ni and Ce as an active layer. The surface morphology and crystal structure of the electrode were characterized by scanning electron microscope(SEM), energy dispersive spectrometer(EDS), and X-Ray diffraction(XRD). The electrochemical performance of the electrodes was tested by linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and electrode life test. The results show that the novel porous Ni-Ce-PbO2 electrodes with larger active surface area have better electrochemical activity and longer electrode life than porous undoped PbO2 electrodes and flat Ni-Ce-PbO2 electrodes. In this work, the removal of Cl− in simulated wastewater on three electrodes was also studied. The results show that the removal effect of the porous Ni-Ce-PbO2 electrode is obviously better than the other two electrodes, and the removal rate is 87.4%, while the removal rates of the other two electrodes were 72.90% and 80.20%, respectively. In addition, the mechanism of electrochemical dechlorinating was also studied. With the progress of electrolysis, we find that the increase of OH- inhibits the degradation of Cl−, however, the porous Ni-Ce-PbO2 electrode can effectively improve the removal of Cl−. Full article
(This article belongs to the Special Issue Electrolysis Processes)
►▼ Show Figures

Figure 1

17 pages, 4487 KiB  
Article
Steady-State Water Drainage by Oxygen in Anodic Porous Transport Layer of Electrolyzers: A 2D Pore Network Study
by Haashir Altaf, Nicole Vorhauer, Evangelos Tsotsas and Tanja Vidaković-Koch
Processes 2020, 8(3), 362; https://doi.org/10.3390/pr8030362 - 21 Mar 2020
Cited by 21 | Viewed by 3990
Abstract
Recently, pore network modelling has been attracting attention in the investigation of electrolysis. This study focuses on a 2D pore network model with the purpose to study the drainage of water by oxygen in anodic porous transport layers (PTL). The oxygen gas produced [...] Read more.
Recently, pore network modelling has been attracting attention in the investigation of electrolysis. This study focuses on a 2D pore network model with the purpose to study the drainage of water by oxygen in anodic porous transport layers (PTL). The oxygen gas produced at the anode catalyst layer by the oxidation of water flows counter currently to the educt through the PTL. When it invades the water-filled pores of the PTL, the liquid is drained from the porous medium. For the pore network model presented here, we assume that this process occurs in distinct steps and applies classical rules of invasion percolation with quasi-static drainage. As the invasion occurs in the capillary-dominated regime, it is dictated by the pore structure and the pore size distribution. Viscous and liquid film flows are neglected and gravity forces are disregarded. The curvature of the two-phase interface within the pores, which essentially dictates the invasion process, is computed from the Young Laplace equation. We show and discuss results from Monte Carlo pore network simulations and compare them qualitatively to microfluidic experiments from literature. The invasion patterns of different types of PTLs, i.e., felt, foam, sintered, are compared with pore network simulations. In addition to this, we study the impact of pore size distribution on the phase patterns of oxygen and water inside the pore network. Based on these results, it can be recommended that pore network modeling is a valuable tool to study the correlation between kinetic losses of water electrolysis processes and current density. Full article
(This article belongs to the Special Issue Electrolysis Processes)
►▼ Show Figures

Figure 1

18 pages, 3757 KiB  
Article
Facile Synthesis of Bio-Template Tubular MCo2O4 (M = Cr, Mn, Ni) Microstructure and Its Electrochemical Performance in Aqueous Electrolyte
by Deepa Guragain, Camila Zequine, Ram K Gupta and Sanjay R Mishra
Processes 2020, 8(3), 343; https://doi.org/10.3390/pr8030343 - 16 Mar 2020
Cited by 18 | Viewed by 3781
Abstract
In this project, we present a comparative study of the electrochemical performance for tubular MCo2O4 (M = Cr, Mn, Ni) microstructures prepared using cotton fiber as a bio-template. Crystal structure, surface properties, morphology, and electrochemical properties of MCo2O [...] Read more.
In this project, we present a comparative study of the electrochemical performance for tubular MCo2O4 (M = Cr, Mn, Ni) microstructures prepared using cotton fiber as a bio-template. Crystal structure, surface properties, morphology, and electrochemical properties of MCo2O4 are characterized using X-ray diffraction (XRD), gas adsorption, scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), cyclic voltammetry (CV), and galvanostatic charge-discharge cycling (GCD). The electrochemical performance of the electrode made up of tubular MCo2O4 structures was evaluated in aqueous 3M KOH electrolytes. The as-obtained templated MCo2O4 microstructures inherit the tubular morphology. The large-surface-area of tubular microstructures leads to a noticeable pseudocapacitive property with the excellent electrochemical performance of NiCo2O4 with specific capacitance value exceeding 407.2 F/g at 2 mV/s scan rate. In addition, a Coulombic efficiency ~100%, and excellent cycling stability with 100% capacitance retention for MCo2O4 was noted even after 5000 cycles. These tubular MCo2O4 microstructure display peak power density is exceeding 7000 W/Kg. The superior performance of the tubular MCo2O4 microstructure electrode is attributed to their high surface area, adequate pore volume distribution, and active carbon matrix, which allows effective redox reaction and diffusion of hydrated ions. Full article
(This article belongs to the Special Issue Electrolysis Processes)
►▼ Show Figures

Figure 1

14 pages, 3986 KiB  
Article
Acid-Base Flow Battery, Based on Reverse Electrodialysis with Bi-Polar Membranes: Stack Experiments
by Jiabing Xia, Gerhart Eigenberger, Heinrich Strathmann and Ulrich Nieken
Processes 2020, 8(1), 99; https://doi.org/10.3390/pr8010099 - 11 Jan 2020
Cited by 36 | Viewed by 7565
Abstract
Neutralization of acid and base to produce electricity in the process of reverse electrodialysis with bipolar membranes (REDBP) presents an interesting but until now fairly overlooked flow battery concept. Previously, we presented single-cell experiments, which explain the principle and discuss the potential of [...] Read more.
Neutralization of acid and base to produce electricity in the process of reverse electrodialysis with bipolar membranes (REDBP) presents an interesting but until now fairly overlooked flow battery concept. Previously, we presented single-cell experiments, which explain the principle and discuss the potential of this process. In this contribution, we discuss experiments with REDBP stacks at lab scale, consisting of 5 to 20 repeating cell units. They demonstrate that the single-cell results can be extrapolated to respective stacks, although additional losses have to be considered. As in other flow battery stacks, losses by shunt currents through the parallel electrolyte feed/exit lines increases with the number of connected cell units, whereas the relative importance of electrode losses decreases with increasing cell number. Experimental results are presented with 1 mole L−1 acid (HCl) and base (NaOH) for open circuit as well as for charge and discharge with up to 18 mA/cm2 current density. Measures to further increase the efficiency of this novel flow battery concept are discussed. Full article
(This article belongs to the Special Issue Electrolysis Processes)
►▼ Show Figures

Figure 1

12 pages, 3808 KiB  
Article
Extreme Learning Machine-Based Model for Solubility Estimation of Hydrocarbon Gases in Electrolyte Solutions
by Narjes Nabipour, Amir Mosavi, Alireza Baghban, Shahaboddin Shamshirband and Imre Felde
Processes 2020, 8(1), 92; https://doi.org/10.3390/pr8010092 - 09 Jan 2020
Cited by 26 | Viewed by 4021
Abstract
Calculating hydrocarbon components solubility of natural gases is known as one of the important issues for operational works in petroleum and chemical engineering. In this work, a novel solubility estimation tool has been proposed for hydrocarbon gases—including methane, ethane, propane, and butane—in aqueous [...] Read more.
Calculating hydrocarbon components solubility of natural gases is known as one of the important issues for operational works in petroleum and chemical engineering. In this work, a novel solubility estimation tool has been proposed for hydrocarbon gases—including methane, ethane, propane, and butane—in aqueous electrolyte solutions based on extreme learning machine (ELM) algorithm. Comparing the ELM outputs with a comprehensive real databank which has 1175 solubility points yielded R-squared values of 0.985 and 0.987 for training and testing phases respectively. Furthermore, the visual comparison of estimated and actual hydrocarbon solubility led to confirm the ability of proposed solubility model. Additionally, sensitivity analysis has been employed on the input variables of model to identify their impacts on hydrocarbon solubility. Such a comprehensive and reliable study can help engineers and scientists to successfully determine the important thermodynamic properties, which are key factors in optimizing and designing different industrial units such as refineries and petrochemical plants. Full article
(This article belongs to the Special Issue Electrolysis Processes)
►▼ Show Figures

Figure 1

15 pages, 6178 KiB  
Article
Investigation and Improvement of Scalable Oxygen Reducing Cathodes for Microbial Fuel Cells by Spray Coating
by Thorben Muddemann, Dennis Haupt, Bolong Jiang, Michael Sievers and Ulrich Kunz
Processes 2020, 8(1), 11; https://doi.org/10.3390/pr8010011 - 19 Dec 2019
Cited by 4 | Viewed by 3443
Abstract
This contribution describes the effect of the quality of the catalyst coating of cathodes for wastewater treatment by microbial fuel cells (MFC). The increase in coating quality led to a strong increase in MFC performance in terms of peak power density and long-term [...] Read more.
This contribution describes the effect of the quality of the catalyst coating of cathodes for wastewater treatment by microbial fuel cells (MFC). The increase in coating quality led to a strong increase in MFC performance in terms of peak power density and long-term stability. This more uniform coating was realized by an airbrush coating method for applying a self-developed polymeric solution containing different catalysts (MnO2, MoS2, Co3O4). In addition to the possible automation of the presented coating, this method did not require a calcination step. A cathode coated with catalysts, for instance, MnO2/MoS2 (weight ratio 2:1), by airbrush method reached a peak and long-term power density of 320 and 200–240 mW/m2, respectively, in a two-chamber MFC. The long-term performance was approximately three times higher than a cathode with the same catalyst system but coated with the former paintbrush method on a smaller cathode surface area. This extraordinary increase in MFC performance confirmed the high impact of catalyst coating quality, which could be stronger than variations in catalyst concentration and composition, as well as in cathode surface area. Full article
(This article belongs to the Special Issue Electrolysis Processes)
►▼ Show Figures

Figure 1

14 pages, 4452 KiB  
Article
Preparation and Characterization of Porous Ti/SnO2–Sb2O3/PbO2 Electrodes for the Removal of Chloride Ions in Water
by Kangdong Xu, Jianghua Peng, Pan Chen, Wankai Gu, Yunbai Luo and Ping Yu
Processes 2019, 7(10), 762; https://doi.org/10.3390/pr7100762 - 18 Oct 2019
Cited by 14 | Viewed by 3838
Abstract
Porous Ti/SnO2–Sb2O3/PbO2 electrodes for electrocatalytic oxidation of chloride ions were studied by exploring the effects of different operating conditions, including pore size, initial concentration, current density, initial pH, electrode plate spacing, and the number of cycles. [...] Read more.
Porous Ti/SnO2–Sb2O3/PbO2 electrodes for electrocatalytic oxidation of chloride ions were studied by exploring the effects of different operating conditions, including pore size, initial concentration, current density, initial pH, electrode plate spacing, and the number of cycles. In addition, a physicochemical characterization and an electrochemical characterization of the porous Ti/SnO2–Sb2O3/PbO2 electrodes were performed. The results showed that Ti/SnO2–Sb2O3/PbO2 electrodes with 150 µm pore size had the best removal effect on chloride ions with removal ratios amounting up to 98.5% when the initial concentration was 10 g L−1, the current density 125 mA cm−2, the initial pH = 9, and the electrode plate spacing 0.5 cm. The results, moreover, showed that the oxygen evolution potential of 150 µm porous Ti/SnO2-Sb2O3/PbO2 electrodes was highest, which minimized side reactions involving oxygen formation and which increased the removal effect of chloride ions. Full article
(This article belongs to the Special Issue Electrolysis Processes)
►▼ Show Figures

Figure 1

23 pages, 5652 KiB  
Article
Pore Network Simulation of Gas-Liquid Distribution in Porous Transport Layers
by Nicole Vorhauer, Haashir Altaf, Evangelos Tsotsas and Tanja Vidakovic-Koch
Processes 2019, 7(9), 558; https://doi.org/10.3390/pr7090558 - 23 Aug 2019
Cited by 16 | Viewed by 4374
Abstract
Pore network models are powerful tools to simulate invasion and transport processes in porous media. They are widely applied in the field of geology and the drying of porous media, and have recently also received attention in fuel cell applications. Here we want [...] Read more.
Pore network models are powerful tools to simulate invasion and transport processes in porous media. They are widely applied in the field of geology and the drying of porous media, and have recently also received attention in fuel cell applications. Here we want to describe and discuss how pore network models can be used as a prescriptive tool for future water electrolysis technologies. In detail, we suggest in a first approach a pore network model of drainage for the prediction of the oxygen and water invasion process inside the anodic porous transport layer at high current densities. We neglect wetting liquid films and show that, in this situation, numerous isolated liquid clusters develop when oxygen invades the pore network. In the simulation with narrow pore size distribution, the volumetric ratio of the liquid transporting clusters connected between the catalyst layer and the water supply channel is only around 3% of the total liquid volume contained inside the pore network at the moment when the water supply route through the pore network is interrupted; whereas around 40% of the volume is occupied by the continuous gas phase. The majority of liquid clusters are disconnected from the water supply routes through the pore network if liquid films along the walls of the porous transport layer are disregarded. Moreover, these clusters hinder the countercurrent oxygen transport. A higher ratio of liquid transporting clusters was obtained for greater pore size distribution. Based on the results of pore network drainage simulations, we sketch a new route for the extraction of transport parameters from Monte Carlo simulations, incorporating pore scale flow computations and Darcy flow. Full article
(This article belongs to the Special Issue Electrolysis Processes)
►▼ Show Figures

Figure 1

14 pages, 8948 KiB  
Article
Experimental Study of Micro Electrochemical Discharge Machining of Ultra-Clear Glass with a Rotating Helical Tool
by Yong Liu, Chao Zhang, Songsong Li, Chunsheng Guo and Zhiyuan Wei
Processes 2019, 7(4), 195; https://doi.org/10.3390/pr7040195 - 04 Apr 2019
Cited by 20 | Viewed by 5029
Abstract
Electrochemical discharge machining (ECDM) is one effective way to fabricate non-conductive materials, such as quartz glass and ceramics. In this paper, the mathematical model for the machining process of ECDM was established. Then, sets of experiments were carried out to investigate the machining [...] Read more.
Electrochemical discharge machining (ECDM) is one effective way to fabricate non-conductive materials, such as quartz glass and ceramics. In this paper, the mathematical model for the machining process of ECDM was established. Then, sets of experiments were carried out to investigate the machining localization of ECDM with a rotating helical tool on ultra-clear glass. This paper discusses the effects of machining parameters including pulse voltage, duty factor, pulse frequency and feed rate on the side gap under different machining methods including electrochemical discharge drilling, electrochemical discharge milling and wire ECDM with a rotary helical tool. Finally, using the optimized parameters, ECDM with a rotary helical tool was a prospective method for machining micro holes, micro channels, micro slits, three-dimensional structures and complex closed structures with above ten micrometers side gaps on ultra-clear glass. Full article
(This article belongs to the Special Issue Electrolysis Processes)
►▼ Show Figures

Figure 1

Review

Jump to: Editorial, Research

23 pages, 1088 KiB  
Review
Alkaline Water Electrolysis Powered by Renewable Energy: A Review
by Jörn Brauns and Thomas Turek
Processes 2020, 8(2), 248; https://doi.org/10.3390/pr8020248 - 21 Feb 2020
Cited by 344 | Viewed by 83247
Abstract
Alkaline water electrolysis is a key technology for large-scale hydrogen production powered by renewable energy. As conventional electrolyzers are designed for operation at fixed process conditions, the implementation of fluctuating and highly intermittent renewable energy is challenging. This contribution shows the recent state [...] Read more.
Alkaline water electrolysis is a key technology for large-scale hydrogen production powered by renewable energy. As conventional electrolyzers are designed for operation at fixed process conditions, the implementation of fluctuating and highly intermittent renewable energy is challenging. This contribution shows the recent state of system descriptions for alkaline water electrolysis and renewable energies, such as solar and wind power. Each component of a hydrogen energy system needs to be optimized to increase the operation time and system efficiency. Only in this way can hydrogen produced by electrolysis processes be competitive with the conventional path based on fossil energy sources. Conventional alkaline water electrolyzers show a limited part-load range due to an increased gas impurity at low power availability. As explosive mixtures of hydrogen and oxygen must be prevented, a safety shutdown is performed when reaching specific gas contamination. Furthermore, the cell voltage should be optimized to maintain a high efficiency. While photovoltaic panels can be directly coupled to alkaline water electrolyzers, wind turbines require suitable converters with additional losses. By combining alkaline water electrolysis with hydrogen storage tanks and fuel cells, power grid stabilization can be performed. As a consequence, the conventional spinning reserve can be reduced, which additionally lowers the carbon dioxide emissions. Full article
(This article belongs to the Special Issue Electrolysis Processes)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-11
Back to TopTop