Magnetohydrodynamic Effect in Electrochemical Processes: Magnetoelectrodeposition, Magnetoelectrocatalysis, and Related Studies

A special issue of Magnetochemistry (ISSN 2312-7481). This special issue belongs to the section "Magnetic Materials".

Deadline for manuscript submissions: 31 March 2024 | Viewed by 18190

Special Issue Editors

Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY 13699, USA
Interests: bioelectronics; bionanotechnology; bioelectrochemistry; biosensors; self-assembling enzymes; monolayers; modified electrodes
Special Issues, Collections and Topics in MDPI journals
MATIM (Materials and Mechanical Engineering), University of Reims Champagne-Ardenne, B.P. 1039, 51687 Reims, CEDEX 2, France
Interests: crystal growth; electrodeposition; nanomaterials; magnetoelectrolysis; oxide; inorganic compounds; alloy; doped oxide

Special Issue Information

Dear Colleague,

The magnetohydrodynamic effect has found numerous applications in different areas of electrochemistry and bioelectrochemistry, including (bio)electrocatalysis, (bio)fuel cells, magnetoelectrodeposition, etc. Recent theoretical work has recently been performed to explain some features of the electrochemical processes in the presence of an external magnetic field.

Magnetoelectrodeposition (electrodeposition carried out under a magnetic field) has been particularly studied for various applications, being one of the most actively studied sub-areas of the magnetoelectrochemistry. Thanks to this technique, it is possible to significantly modify the deposits of metals, alloys, and inorganic (oxide, etc.) and organic compounds (polymers, etc.). The growing interest in the superimposition of a static or an alternating magnetic field during electrodeposition shows how much this technique can improve the quality of deposits from both a morphological and structural point of view. A magnetic field is a very useful tool that allows the tailoring of different deposit properties and characteristics such as grain size, texture, density, morphology, and roughness. Due to specific forces and induced convection, a magnetic field can act on the mass transport process and modify the growth mechanism. It is also important to learn more about how MHD and micro-MHD forces could influence the kinetics of chemical reactions in the electrical double layer and act on gas evolution.

This Special Issue of the open access journal Magnetochemistry, devoted to " Magnetohydrodynamic Effect in Electrochemical Processes: Magnetoelectrodeposition, Magnetoelectrocatalysis, and Related Studies", will provide researchers in the field the opportunity to publish their most recent results on these techniques.

Prof. Dr. Evgeny Katz
Dr. Anne-Lise Daltin
Guest Editors

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Keywords

  • electrodeposition
  • Kelvin force
  • Lorentz force
  • magnetic field
  • magnetoelectrodeposition
  • magnetoelectrolysis
  • magnetohydrodynamics
  • MHD effect
  • (bio)electrocatalysis
  • (bio)fuel cells

Published Papers (9 papers)

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Research

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66 pages, 6727 KiB  
Article
Theory of Chiral Electrodeposition by Chiral Micro-Nano-Vortices under a Vertical Magnetic Field -1: 2D Nucleation by Micro-Vortices
Magnetochemistry 2022, 8(7), 71; https://doi.org/10.3390/magnetochemistry8070071 - 06 Jul 2022
Cited by 1 | Viewed by 1682
Abstract
Remarkable chiral activity is donated to a copper deposit surface by magneto-electrodeposition, whose exact mechanism has been clarified by the three-generation model. In copper deposition under a vertical magnetic field, a macroscopic tornado-like rotation called the vertical magnetohydrodynamic (MHD) flow (VMHDF) emerges on [...] Read more.
Remarkable chiral activity is donated to a copper deposit surface by magneto-electrodeposition, whose exact mechanism has been clarified by the three-generation model. In copper deposition under a vertical magnetic field, a macroscopic tornado-like rotation called the vertical magnetohydrodynamic (MHD) flow (VMHDF) emerges on a disk electrode, inducing the precessional motions of various chiral microscopic MHD vortices: First, chiral two-dimensional (2D) nuclei develop on an electrode by micro-MHD vortices. Then, chiral three-dimensional (3D) nuclei grow on a chiral 2D nucleus by chiral nano-MHD vortices. Finally, chiral screw dislocations are created on a chiral 3D nucleus by chiral ultra-micro MHD vortices. These three processes constitute nesting boxes, leading to a limiting enantiomeric excess (ee) ratio of 0.125. This means that almost all chiral activity of copper electrodes made by this method cannot exceed 0.125. It also became obvious that chirality inversion by chloride additive arises from the change from unstable to stable nucleation by the specific adsorption of it. Full article
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20 pages, 9469 KiB  
Article
Corrosion Behavior of ZnMn Coatings Magnetoelectrodeposited
Magnetochemistry 2022, 8(7), 69; https://doi.org/10.3390/magnetochemistry8070069 - 26 Jun 2022
Viewed by 1642
Abstract
The zinc–manganese alloy coatings have been obtained without and with superimposition of a 0.3 T magnetic field in a parallel direction to the working surface electrode. The electrodeposition during 30 min, for two applied potentials (E = −1.6 V/SCE and E = −1.8 [...] Read more.
The zinc–manganese alloy coatings have been obtained without and with superimposition of a 0.3 T magnetic field in a parallel direction to the working surface electrode. The electrodeposition during 30 min, for two applied potentials (E = −1.6 V/SCE and E = −1.8 V/SCE) in an electrochemical bath with the (Zn2+)/(Mn2+) concentration ratio equal to 0.5. The structural, the morphological, and the chemical composition characteristics of the deposits have been studied. It has been found that the applied potentials modify the structural properties of the deposits, η phase-rich deposits elaborated for E = −1.6 V/SCE, and MnZn3-rich deposits elaborated for E = −1.8 V/SCE. The magnetohydrodynamic convection favors the manganese content of the deposit. The corrosion behavior of these coatings has been analyzed in 3.5% NaCl solution by free corrosion potential measurements and electrochemical impedance spectroscopy. The different results show that the corrosion resistance of these zinc–manganese alloy coatings is linked to their structure, to their composition, and to the magnetic field amplitude used during the electrodeposition process. Full article
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12 pages, 2059 KiB  
Article
Pulse Reverse Plating of Copper Micro-Structures in Magnetic Gradient Fields
Magnetochemistry 2022, 8(7), 66; https://doi.org/10.3390/magnetochemistry8070066 - 22 Jun 2022
Cited by 2 | Viewed by 1502
Abstract
Micro-structured copper layers are obtained from pulse-reverse electrodeposition on a planar gold electrode that is magnetically patterned by magnetized iron wires underneath. 3D numerical simulations of the electrodeposition based on an adapted reaction kinetics are able to nicely reproduce the micro-structure of the [...] Read more.
Micro-structured copper layers are obtained from pulse-reverse electrodeposition on a planar gold electrode that is magnetically patterned by magnetized iron wires underneath. 3D numerical simulations of the electrodeposition based on an adapted reaction kinetics are able to nicely reproduce the micro-structure of the deposit layer, despite the height values still remain underestimated. It is shown that the structuring is enabled by the magnetic gradient force, which generates a local flow that supports deposition and hinders dissolution in the regions of high magnetic gradients. The Lorentz force originating from radial magnetic field components near the rim of the electrode causes a circumferential cell flow. The resulting secondary flow, however, is superseded by the local flow driven by the magnetic gradient force in the vicinity of the wires. Finally, the role of solutal buoyancy effects is discussed to better understand the limitations of structured growth in different modes of deposition and cell geometries. Full article
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9 pages, 3762 KiB  
Article
Influence of a Constant Perpendicular High Magnetic Field on the Electrodeposition of Calcium Phosphate Coating
Magnetochemistry 2022, 8(6), 62; https://doi.org/10.3390/magnetochemistry8060062 - 07 Jun 2022
Cited by 1 | Viewed by 1475
Abstract
Calcium phosphate coatings were formed on a Ti6Al4V substrate by electrodeposition under a high magnetic field up to 16 T. The magnetic field was parallelly applied to the vertical surface electrode. Changes in crystal morphology of calcium phosphates were investigated as a function [...] Read more.
Calcium phosphate coatings were formed on a Ti6Al4V substrate by electrodeposition under a high magnetic field up to 16 T. The magnetic field was parallelly applied to the vertical surface electrode. Changes in crystal morphology of calcium phosphates were investigated as a function of the magnetic field amplitude, and the results are discussed in terms of magnetic field effects. Magnetohydrodynamic convection due to the Lorentz force could considerably reduce the formation of volcano-like structures and generate more uniform deposits without changing Ca/P ratios. Full article
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23 pages, 6776 KiB  
Article
Magnetohydrodynamic Effects on Third-Grade Fluid Flow and Heat Transfer with Darcy–Forchheimer Law over an Inclined Exponentially Stretching Sheet Embedded in a Porous Medium
Magnetochemistry 2022, 8(6), 61; https://doi.org/10.3390/magnetochemistry8060061 - 06 Jun 2022
Cited by 23 | Viewed by 1759
Abstract
The major aim of the current investigations is to study the magnetohydrodynamic effects on heat and mass transfer phenomena in third-grade fluid past an inclined exponentially stretching sheet fixed in a porous medium with Darcy–Forchheimer law influence. The constitutive equations compatible for heat [...] Read more.
The major aim of the current investigations is to study the magnetohydrodynamic effects on heat and mass transfer phenomena in third-grade fluid past an inclined exponentially stretching sheet fixed in a porous medium with Darcy–Forchheimer law influence. The constitutive equations compatible for heat and mass transportation in third-grade fluid in terms of partial differential equations are modeled. These partial differential equations are then converted to ordinary differential equations by using suitable similarity variables formulation. The transformed flow model is solved by using MATLAB built-in numerical solver bvp4c. Effects of pertinent parameters on physical properties that are velocity field, temperature field and mass concentration along with skin friction coefficient, Nusselt number and Sherwood number are demonstrated in graphs and tables. The impact of dimensionless numbers on the physical properties is analyzed and discussed with a physical view point at angle  α=π/6 (inclined sheet). It is seen that as the third-grade fluid parameter (0.1β11) is increased, the velocity profile increases, but the temperature field and mass concentration are decreased. It is observed that as the permeability parameter (1K*11) is raised, the velocity distribution decreases and mass concentration increases. It is concluded from the results that owing to an increase in the local inertial coefficient (0.1Fr5), the velocity profile reduces but an increment in mass concentration is noted. It is concluded that by increasing values of magnetic field parameter (0.1M10) the velocity field is delineated and temperature field is elevated exactly according to the physics of magnetic field parameters. The present results are compared with already published results and it is observed that there is good agreement between them. This good agreement ensures the validation of accuracy of the results. Full article
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11 pages, 4458 KiB  
Article
Studying the Effect of Electrode Material and Magnetic Field on Hydrogen Production Efficiency
Magnetochemistry 2022, 8(5), 53; https://doi.org/10.3390/magnetochemistry8050053 - 07 May 2022
Cited by 6 | Viewed by 3082
Abstract
Water electrolysis is one of the most common methods to produce hydrogen gas with high purity, but its application is limited due to its low energy efficiency. It has been proved that an external magnetic field can reduce energy consumption and increase hydrogen [...] Read more.
Water electrolysis is one of the most common methods to produce hydrogen gas with high purity, but its application is limited due to its low energy efficiency. It has been proved that an external magnetic field can reduce energy consumption and increase hydrogen production efficiency in water electrolysis. In this study, electrodes with different magnetism were subjected to a perpendicular magnetic field for use in hydrogen production by water electrolysis. Gas bubbles that evolve from the surface of a horizontal electrode detach faster than the bubbles from a vertical electrode. The locomotion of the bubbles is facilitated if the horizontal electrode faces a magnet, which induces the revolution of bubbles between the electrodes. However, the magnetic field does not increase the current density effectively if the electrodes are more than 5 cm apart. A paramagnetic (platinum) electrode has a more significant effect on bubble locomotion than a diamagnetic (graphite) material and is able to increase the efficiency of electrolysis more effectively when a perpendicular magnetic field is applied. The conductivity of platinum electrodes that face a magnet increases if the distance between the electrodes is less than 4 cm, but the conductivity of graphite electrodes does not increase until the inter-electrode distance is reduced to 2 cm. On the other hand, horizontal graphite electrodes that are subjected to a perpendicular magnetic field will generate a higher gas production rate than a platinum electrode without a magnetic field if the inter-electrode distance is less than 1 cm. Full article
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10 pages, 2284 KiB  
Article
Use of Time Domain Nuclear Magnetic Resonance Relaxometry to Monitor the Effect of Magnetic Field on the Copper Corrosion Rate in Real Time
Magnetochemistry 2022, 8(4), 40; https://doi.org/10.3390/magnetochemistry8040040 - 06 Apr 2022
Cited by 1 | Viewed by 2347
Abstract
The corrosion of metals is a major problem of modern societies, demanding new technologies and studies to understand and minimize it. Here we evaluated the effect of a magnetic field (B) on the corrosion of copper in aqueous HCl solution under [...] Read more.
The corrosion of metals is a major problem of modern societies, demanding new technologies and studies to understand and minimize it. Here we evaluated the effect of a magnetic field (B) on the corrosion of copper in aqueous HCl solution under open circuit potential. The corrosion product, Cu2+, is a paramagnetic ion and its concentration in the solution was determined in real time in the corrosion cell by time-domain NMR relaxometry. The results show that the magnetic field (B = 0.23 T) of the time-domain NMR instrument reduces the corrosion rate by almost 50%, in comparison to when the corrosion reaction is performed in the absence of B. Atomic force microscopy and X-ray diffraction results of the analysis of the corroded surfaces reveal a detectable CuCl phase and an altered morphology when B is present. The protective effect of B was explained by magnetic forces that maintain the Cu2+ in the solution/metal interface for a longer time, hindering the arrival of the new corrosive agents, and leading to the formation of a CuCl phase, which may contribute to the rougher surface. The time-domain NMR method proved to be useful to study the effect of B in the corrosion of other metals or other corrosive liquid media when the reactions produce or consume paramagnetic ions. Full article
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Review

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21 pages, 1882 KiB  
Review
Applications of Magneto Electrochemistry and Magnetohydrodynamics in Microfluidics
Magnetochemistry 2022, 8(11), 140; https://doi.org/10.3390/magnetochemistry8110140 - 26 Oct 2022
Cited by 5 | Viewed by 1983
Abstract
Magnetic fields affect electrolytes in diverse ways. This paper focuses on the interactions among electric, magnetic, and flow fields and the applications of the resulting phenomena in microfluidics. When an electrical current is transmitted in an electrolyte in the presence of an external [...] Read more.
Magnetic fields affect electrolytes in diverse ways. This paper focuses on the interactions among electric, magnetic, and flow fields and the applications of the resulting phenomena in microfluidics. When an electrical current is transmitted in an electrolyte in the presence of an external magnetic field, a Lorentz body force results, which may induce pressure gradients and fluid motion—magnetohydrodynamics (MHD). The resulting advection is used to pump fluids, induce/suppress flow instabilities, and control mass transfer in diverse electrochemical processes. When an electrolyte flows in the presence of a magnetic field, electromotive force (emf) is induced in the electrolyte and can be used for flow metering, hydrogen production, and energy conversion. This review describes the governing equations for modeling MHD flows in electrolytes and MHD phenomena and applications relevant to microfluidic systems, such as the use of MHD to pump and stir fluids, propel swimmers, and control fluid flow in fluidic networks without any mechanical components. The paper also briefly assesses the impact of magnetic resonance imaging (MRI) on blood flow. MHD in electrolytes is a highly interdisciplinary, combining electrokinetics, fluid mechanics, electrochemistry, and Maxwell equations. Full article
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14 pages, 4824 KiB  
Review
Breaking of Odd Chirality in Magnetoelectrodeposition
Magnetochemistry 2022, 8(7), 67; https://doi.org/10.3390/magnetochemistry8070067 - 23 Jun 2022
Cited by 1 | Viewed by 1223
Abstract
Electrodeposition under magnetic fields (magnetoelectrodeposition; MED) can induce surface chirality on copper films. The chiral signs of MED films should depend on the magnetic field polarity; namely, the reversal of the magnetic field causes the opposite chiral sign. This represents odd chirality for [...] Read more.
Electrodeposition under magnetic fields (magnetoelectrodeposition; MED) can induce surface chirality on copper films. The chiral signs of MED films should depend on the magnetic field polarity; namely, the reversal of the magnetic field causes the opposite chiral sign. This represents odd chirality for the magnetic field polarity. However, odd chirality was broken in several MED conditions. This paper makes a survey of breaking of odd chirality in the MED conditions such as low magnetic fields, specific adsorption of chloride ions, micro-electrode, and cell rotation. These results indicate that the ordered fluctuation of magnetohydrodynamic micro-vortices induces the breaking of odd chirality and that the random fluctuation results in the disappearance of surface chirality. Full article
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