Hechter, Ernst Heznz2024-10-302024-10-302024Hechter, Ernst Heznz . (2024). Magnetic enhancement of a high entropy spinel oxide electrocatalyst for rechargeable zinc-air batteries [Master’s dissertation, University of the Witwatersrand, Johannesburg]. WIReDSpace.https://hdl.handle.net/10539/42142A Dissertation submitted in fulfillment of the requirements for the degree of Master of Science (Chemistry) to the Faculty of Science, School of Chemistry, University of the Witwatersrand, Johannesburg, 2024The exploration of high entropy materials (HEMs) as electrocatalyst materials has only recently begun to accelerate. Similarly, the effect of magnetic fields on the oxygen evolution and reduction reactions has recently begun to attract great interest. In this work nanoparticles of the high entropy oxide (CuCoFeMnNi)3O4 were synthesized and supported on Vulcan carbon for use as a bifunctional OER/ORR catalyst in a rechargeable zinc-air battery (RZAB). The products were characterized to confirm and investigate the solid solution high entropy phase, and the electrochemistry was investigated with and without an external magnetic field. The HEMs demonstrated moderate intrinsic electrochemical properties, with overpotentials and current densities comparable to commercial platinum on carbon catalysts even at low loadings. Here is reported the most significant magnetic enhancement in RZAB power profile in literature at the time of writing, as well as improved RZAB stability and areal energy. This work offers insight into the mechanism of magnetic enhancement in the case of high entropy materials, and pioneers the use of combined strategies to achieve stable, cost-efficient and effective bifunctional OER/ORR electrocatalysis.en© 2024 University of the Witwatersrand, Johannesburg. All rights reserved. The copyright in this work vests in the University of the Witwatersrand, Johannesburg. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of University of the Witwatersrand, Johannesburg.Rechargeable zinc-air batteriesHigh entropy materials (HEMs)Oxygen evolution and reductionUCTDSDG-7: Affordable and clean energyDissertationUniversity of the Witwatersrand, Johannesburg