Resorcinol-derived carbon-based catalysts for polymer electrolyte fuel cell cathodes
Date
2024-07-11
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Abstract
Euroopa Komisjoni ettepanek vesiniku kasutuselevõtuks on kiirendanud vesinikutehnoloogiate arengut, et liikuda jätkusuutlike energialahenduste poole. Polümeerelektrolüüt- kütuseelemendid, mis kasutavad kütusena vesinikku, on sobivaks energiaallikaks erinevate rakenduste jaoks, sealhulgas autotööstuses, merenduses ja varutoitena. Hoolimata edusammudest kütuseelemendi tehnoloogias on nende kasutuselevõtt võrreldes akudega olnud aeglasem, mille üheks põhjuseks on kütuseelementides katalüsaatorina kasutatava plaatina nappus ja kõrge hind. Probleemi lahendamiseks keskendub käesolev doktoritöö väärismetallivabade hapniku redutseerumisreaktsiooni elektrokatalüsaatorite arendamisele kütuseelemendi katoodi jaoks. Töö eesmärk on töötada välja sünteesimeetodeid katalüsaatorite valmistamiseks pürolüüsi teel, kasutades süsiniku lähteainena alküülresortsinoole. Varieeriti sünteesitingimusi ja optimeeriti lähteainete suhteid, et saavutada kõrgeim hapniku redutseerumise elektrokatalüütiline aktiivsus. Lisaks uuriti süsinikmaterjali poorse struktuuri mõju kütuselemendi jõudlusele, kasutades sünteesiprotsessis magneesiumipõhiseid matriitse. Katalüsaatoreid iseloomustati põhjalikult füüsikalis-keemiliste meetoditega, et mõista nende struktuuri ja elektrokatalüütilise aktiivsuse vahelisi seoseid. Katalüsaatorite elektrokeemilist aktiivsust testiti pöörleva ketaselektroodi või pöörleva rõngas-ketaselektroodi meetodil ning sünteesitud materjale kasutati katoodkatalüsaatoritena nii anioonivahetusmembraaniga kui ka prootonivahetusmembraaniga kütuseelementides. See doktoritöö püüab lahendada plaatina nappusega seonduvat probleemi, arendades väärismetallivabasid katalüsaatoreid, mis võimaldaksid kütuseelementide laiemat kasutuselevõttu.
The European Commission's proposal to integrate electrolytically produced hydrogen is expected to accelerate the development of hydrogen technologies, to move towards sustainable energy solutions. Polymer electrolyte fuel cells (PEFCs), using hydrogen as the fuel, are a versatile solution across various applications, including automotive, residential, maritime, and backup power. Despite advancements in fuel cell technology, their adoption lags behind batteries, partly due to the scarcity and high price of platinum, a critical component in fuel cell catalysts. To address this issue, research is focused on developing platinum group metal (PGM)-free cathode catalysts to reduce the PGM content in the fuel cell stack significantly. This PhD thesis focuses on developing synthesis methods for PGM-free catalysts for oxygen reduction reaction (ORR) on PEFCs cathodes via pyrolysis, using alkylresorcinols as carbon precursors. Synthesis conditions are varied, and precursor ratios are optimized to achieve the highest electrocatalytic activity toward the ORR. In addition, the effect of the porous structure of carbon materials on the fuel cell performance is studied using magnesium-based templates for catalyst preparation. The catalysts are extensively characterized by physico-chemical methods to understand the relationships between the catalyst structure and electrocatalytic activity. The electrocatalytic performance of the materials is tested using the rotating disc electrode or rotating ring-disc electrode methods, and the synthesized materials are employed as cathode catalysts in both anion exchange membrane and proton exchange membrane fuel cells. This research addresses the crucial issue of Pt scarcity by developing viable PGM-free catalysts, potentially enabling broader and more sustainable adoption of fuel cell technologies.
The European Commission's proposal to integrate electrolytically produced hydrogen is expected to accelerate the development of hydrogen technologies, to move towards sustainable energy solutions. Polymer electrolyte fuel cells (PEFCs), using hydrogen as the fuel, are a versatile solution across various applications, including automotive, residential, maritime, and backup power. Despite advancements in fuel cell technology, their adoption lags behind batteries, partly due to the scarcity and high price of platinum, a critical component in fuel cell catalysts. To address this issue, research is focused on developing platinum group metal (PGM)-free cathode catalysts to reduce the PGM content in the fuel cell stack significantly. This PhD thesis focuses on developing synthesis methods for PGM-free catalysts for oxygen reduction reaction (ORR) on PEFCs cathodes via pyrolysis, using alkylresorcinols as carbon precursors. Synthesis conditions are varied, and precursor ratios are optimized to achieve the highest electrocatalytic activity toward the ORR. In addition, the effect of the porous structure of carbon materials on the fuel cell performance is studied using magnesium-based templates for catalyst preparation. The catalysts are extensively characterized by physico-chemical methods to understand the relationships between the catalyst structure and electrocatalytic activity. The electrocatalytic performance of the materials is tested using the rotating disc electrode or rotating ring-disc electrode methods, and the synthesized materials are employed as cathode catalysts in both anion exchange membrane and proton exchange membrane fuel cells. This research addresses the crucial issue of Pt scarcity by developing viable PGM-free catalysts, potentially enabling broader and more sustainable adoption of fuel cell technologies.
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