Magnetochemistry

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Magnetochemistry, Volume 9, Issue 12 (December 2023) – 2 articles

Cover Story (view full-size image): Employing an external magnetic field can mitigate energy consumption to enhance the water electrolysis efficiency. The electrode–normal magnetic field results in a magnet edge effect, and the electrode edge effect is achieved by varying the sizes of the magnet and electrode, both generating the Lorentz force. The Lorentz force induces a rotational flow, aiding the movement of hydrogen. Hydrogen bubbles produced under the magnet edge effect rotate in the opposite direction to those under the electrode edge effect. The magnet edge effect exerts a more pronounced influence on hydrogen bubble locomotion than the electrode edge effect. Utilizing multiple small magnets beneath the electrode generates enhanced magnet effects, resulting in a more substantial increase in current density. View this paper

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13 pages, 4474 KiB

Open AccessEditor’s ChoiceArticle

Effect of Electrode–Normal Magnetic Field on the Motion of Hydrogen Bubbles

by Yen-Ju Chen, Yan-Hom Li and Ching-Yao Chen

Magnetochemistry 2023, 9(12), 233; https://doi.org/10.3390/magnetochemistry9120233 - 18 Dec 2023

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Abstract

In comparison to alternative methods for hydrogen production, water electrolysis stands out as the optimal means for obtaining ultra-pure hydrogen. However, its widespread adoption is significantly hampered by its low energy efficiency. It has been established that the introduction of an external magnetic field can mitigate energy consumption, consequently enhancing electrolysis efficiency. While much of the research has revealed that an electrode–parallel magnetic field plays a crucial role in enhancing the bubble detachment process, there has been limited exploration of the effect of electrode–normal magnetic fields. In this work, we compare the water electrolysis efficiency of a circular electrode subjected to electrode–normal magnetic field resulting in a magnet edge effect and electrode edge effect by varying the sizes of the magnet and electrode. The findings indicate that a rotational flow caused by the Lorentz force facilitates the detachment of the hydrogen from the electrode surface. However, the rotation direction of hydrogen gas bubbles generated by the magnet edge effect is opposite to that of electrode edge effect. Furthermore, the magnet edge effect has more significant influence on the hydrogen bubbles’ locomotion than the electrode edge effect. With an electrode gap of 30 mm, employing the magnet edge effect generated by a single magnet leads to an average of 4.9% increase in current density. On the other hand, the multiple magnet effects created by multiple small magnets under the electrode can further result in an average 6.6% increase in current density. Nevertheless, at an electrode spacing of 50 mm, neither the magnet edge effect nor the electrode edge effect demonstrates a notable enhancement in conductivity. In reality, the electrode edge effect even leads to a reduction in conductivity. Full article

(This article belongs to the Special Issue Advances in Electrochemical Properties of Magnetic Materials)

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14 pages, 11066 KiB

Open AccessArticle

Effect of Topology Parameters on Physical–Mechanical Properties of Magnetic PLA 3D-Printed Structures

by Lucie Zárybnická, Marek Pagáč, Radek Ševčík, Jaroslav Pokorný and Martin Marek

Magnetochemistry 2023, 9(12), 232; https://doi.org/10.3390/magnetochemistry9120232 - 18 Dec 2023

Viewed by 1519

Abstract

This work aims to characterize 3D-printed structures composed of a thermoplastic material (polylactic acid (PLA)) containing a combination of magnetic particles composed of iron(III) oxide (hematite) and iron(II)–iron (III) oxide (magnetite) with various infill densities and print orientations in regard to their possible processing by Fused Filament Fabrication additive technology. The correct processing temperatures have been determined using thermal analysis, and the paramagnetic and mechanical properties of the samples have been tested. The relative permeability has been identified to be strongly dependent on the topology parameters of the tested samples. The results of the inductance values for the samples without magnetic additives (infill densities 50% and 100%) have been detected to be comparable; nonetheless, the magnetic samples with 100% infill density has been found to be about 50% higher. A similar trend has been observed in the case of the values of the relative permeability, where the magnetic samples with 100% infill density have been measured as having an about 40% increased relative permeability in the comparison with the samples without magnetic additives (infill densities 20–100%). Finite Element Modelling (FEM) simulations have been applied to determine the magnetic field distributions and, moreover, to calculate the holding forces of all the printed samples. The maximum value of the holding force for the minimum distance of the plastic plate has been found to reach a value of almost 300 N (magnetic sample with 100% infill density). The obtained comprehensive characterization of the printed samples may be utilized for designing and tuning the desired properties of the samples needed in various industrial applications. Full article

(This article belongs to the Section Magnetic Materials)

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Magnetochemistry, Volume 9, Issue 12 (December 2023) – 2 articles

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