M-N4 macrocycle-based catalysts for electrocatalysis of oxygen reduction and oxygen evolution
Date
2023-11-24
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Abstract
Bifunktsionaalsed katalüsaatormaterjalid on vajalikud koostisosad mitmesugustes elektrokeemilistes seadmetes, kus nad elektrokatalüüsivad hapniku redutseerimisreaktsiooni ja hapniku eraldumisreaktsiooni. Need reaktsioonid toimuvad mitmetes elektrokeemilistes energia muundamise ja salvestamise tehnoloogiates, näiteks kütuseelementides, metall-õhk akudes ja elektrolüüserites, mis võimaldavad üleminekut fossiilkütustel põhinevatelt energiasüsteemidelt. Doktoritöö eesmärk oli uurida siirdemetallidel põhinevate materjalide bifunktsionaalseid elektrokatalüütilisi omadusi hapniku redutseerimis- ja eraldumis-reaktsioonil. Katalüsaatormaterjalidena kasutati bimetalseid ftalotsüaniinidega dopeeritud süsiniknanotorusid ja teisi süsiniknanomaterjale ning ka polümeersetel võrgustikel põhinevaid siirdemetallidega dopeeritud materjale. Uuringute põhiline fookus oli hapniku redutseerimis- ja eraldumisreaktsiooni elektrokatalüütilist aktiivsust määravate tegurite väljaselgitamine, et leida materjalide struktuuri ja omaduste vahelisi seoseid ning arendada veelgi paremaid katalüsaatoreid. Neid materjale kasutati katoodkatalüsaatorina anioonvahetusmembraaniga kütuseelementides ja õhuelektroodina tsink-õhk akudes, kus need näitasid suurepärast jõudlust ja mõnedki neist ületasid kommertsiaalsete väärismetallkatalüsaatoritega saadud jõudluse. Doktoritöö raames tehtud laiahaardelised uuringud ulatusid uudsete katalüsaatormaterjalide sünteesist kuni nende elektrokeemiliste omaduste süvaanalüüsini, andes seega olulise panuse elektrokatalüüsi valdkonnale.
Bifunctional oxygen electrocatalysts have emerged as pivotal components in a broad spectrum of electrochemical devices, playing a crucial role in facilitating the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). These reactions are crucial in various electrochemical energy conversion and storage technologies, including fuel cells, metal-air batteries and water electrolysers, thereby aiding in the transition away from reliance on fossil fuel-based energy systems. The aim of this doctoral thesis was to explore the electrocatalytic performance of a range of first-row transition metal-based materials for bifunctional oxygen electrocatalysis. These materials encompassed bimetal-doped carbon nanotubes, catalysts doped with metal phthalocyanines on various commercial carbon supports and polymer framework-derived carbon materials doped with transition metals. The specific focus of this investigation was to elucidate the influence of various factors on the ORR and OER activity. The key objective was to develop better electrocatalysts and to establish relationships between their structure and properties. These materials were employed as cathode catalysts in anion-exchange membrane fuel cells and as air electrodes in zinc-air batteries, demonstrating exceptional performance with several of them matching or even surpassing the performance of commercial noble metal-based catalysts. This comprehensive research spanning from the synthesis of novel catalyst materials to the thorough analysis of their electrochemical behaviour, strives to make a meaningful contribution to the dynamic field of electrocatalysis.
Bifunctional oxygen electrocatalysts have emerged as pivotal components in a broad spectrum of electrochemical devices, playing a crucial role in facilitating the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). These reactions are crucial in various electrochemical energy conversion and storage technologies, including fuel cells, metal-air batteries and water electrolysers, thereby aiding in the transition away from reliance on fossil fuel-based energy systems. The aim of this doctoral thesis was to explore the electrocatalytic performance of a range of first-row transition metal-based materials for bifunctional oxygen electrocatalysis. These materials encompassed bimetal-doped carbon nanotubes, catalysts doped with metal phthalocyanines on various commercial carbon supports and polymer framework-derived carbon materials doped with transition metals. The specific focus of this investigation was to elucidate the influence of various factors on the ORR and OER activity. The key objective was to develop better electrocatalysts and to establish relationships between their structure and properties. These materials were employed as cathode catalysts in anion-exchange membrane fuel cells and as air electrodes in zinc-air batteries, demonstrating exceptional performance with several of them matching or even surpassing the performance of commercial noble metal-based catalysts. This comprehensive research spanning from the synthesis of novel catalyst materials to the thorough analysis of their electrochemical behaviour, strives to make a meaningful contribution to the dynamic field of electrocatalysis.
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Väitekirja elektrooniline versioon ei sisalda publikatsioone
Keywords
oxygen, electrocatalysis, transition metals, carbon materials, catalysts, fuel cells