Electrochemical reduction of oxygen on silver-based catalysts
Date
2023-07-17
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Abstract
Vesinikkütuseelemendi tehnoloogia toetab üleilmset roheenergia nõudlust ja võimaldab asendada sõidukite sisepõlemismootorid. Vesinikautode peamiseks puuduseks on nende kõrge hind, mis osaliselt tuleneb vajadusest kasutada kütuseelemendi katoodil toimuva hapniku redutseerumisreaktsiooni kiirendamiseks kalleid plaatinapõhiseid katalüsaatormaterjale. Selle probleemi lahendus võiks olla hõbedat sisaldavate katalüsaatorite kasutamine, mis aluselises keskkonnas on hapniku redutseerumisel aktiivsuselt lähedased plaatinakatalüsaatoritele. Hõbe on tunduvalt odavam kui plaatina ning seda leidub maakoores palju rohkem, kuid hõbedapõhised katalüsaatorid vajavad kõrgema elektrokatalüütilise aktiivsuse ja stabiilsuse saavutamiseks veel optimeerimist. Doktoritöös sünteesiti erinevatel meetoditel hõbedapõhised katalüsaatorid, sadestades Ag nanoosakesi mitmetele süsinikmaterjalidele ning varieerides Ag osakeste suurust ja kogust. Valmistatud materjalide elektrokatalüütilist aktiivsust hapniku redutseerumisel ja stabiilsust uuriti elektrokeemiliste meetoditega. Saadud tulemused näitavad, et hõbedapõhised katalüsaatorid võiksid sobida kasutamiseks anioonivahetusmembraaniga kütuseelemendi katoodil ning seega muuta kütuseelemendid tarbijatele taskukohasemaks.
Hydrogen fuel cell technology has evolved to support global green energy demands and replace internal combustion engines in cars. The main drawback of fuel cell electric vehicles is their high price, which is partly due to the high cost of platinum-based cathode catalysts used in hydrogen fuel cells to enhance the kinetics of oxygen reduction reaction (ORR). A solution to this problem could be the application of silver-based catalysts that in alkaline media show the electrocatalytic activity for ORR approaching to that of Pt catalysts. Silver is cheaper and more abundant than platinum, however, the silver-based catalysts still need optimisation, in order to achieve high ORR activity and stability. In this work, Ag-based catalysts have been synthesised by depositing Ag nanoparticles onto various carbon substrates using different methods and varying the Ag particle size and loading. The electrocatalytic activity and stability of the prepared Ag-based catalysts have been studied. The results obtained show that silver-based materials could indeed replace platinum-based catalysts on the cathode of the anion exchange membrane fuel cell, which in turn would make fuel cells more affordable to the consumers
Hydrogen fuel cell technology has evolved to support global green energy demands and replace internal combustion engines in cars. The main drawback of fuel cell electric vehicles is their high price, which is partly due to the high cost of platinum-based cathode catalysts used in hydrogen fuel cells to enhance the kinetics of oxygen reduction reaction (ORR). A solution to this problem could be the application of silver-based catalysts that in alkaline media show the electrocatalytic activity for ORR approaching to that of Pt catalysts. Silver is cheaper and more abundant than platinum, however, the silver-based catalysts still need optimisation, in order to achieve high ORR activity and stability. In this work, Ag-based catalysts have been synthesised by depositing Ag nanoparticles onto various carbon substrates using different methods and varying the Ag particle size and loading. The electrocatalytic activity and stability of the prepared Ag-based catalysts have been studied. The results obtained show that silver-based materials could indeed replace platinum-based catalysts on the cathode of the anion exchange membrane fuel cell, which in turn would make fuel cells more affordable to the consumers
Description
Väitekirja elektrooniline versioon ei sisalda publikatsioone
Keywords
nanoparticles, silver, catalysts, electrochemical reduction, oxygen