Electrochemical reduction of oxygen on supported Pt catalysts
Date
2019-07-09
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Selle töö eesmärk oli parendada süsinikule seondatud plaatinakatalüsaatorite aktiivsust ja eluiga hapniku elektrokeemilisel redutseerumisel madalatemperatuursetes kütuseelementides. Töös kasutati erinevaid meetodeid Pt nanoosakeste valmistamiseks: magnetrontolmustamist, elektrokeemilist sadestamist, keemilist sünteesi ja fotokeemilist sünteesi. Pinnaanalüüsiks kasutati skaneerivat ja läbistuselektronmikroskoopiat, röntgenfotoelektronspektroskoopiat, röntgendifraktsioonanalüüsi, tsüklilist voltamperomeetriat ja adsorbeerunud CO elektrokeemilist oksüdeerimist. Hapniku elektroredutseerumise kineetikat uuriti põhjalikult pöörleva ketaselektroodi meetodil. Töö esimeses osas sadestati plaatina nanoosakesed süsinikul põhinevatele materjalidele nagu mitmeseinalised süsiniknanotorud ja grafeeni nanoliistakud ja uuriti nende elektrokatalüütilist aktiivsust nii aluselises kui ka happelises lahuses. Töö teises osas keskenduti Pt nanoosakestele, mis olid seondatud metallioksiidide (TiO2 või SnO2) ja süsinikmaterjalide komposiitidele eesmärgiga parandada katalüsaatori stabiilsust ja aktiivsust hapniku redutseerumisel. Põhjaliku testimise tulemused näitasid, et metallioksiidid tõstavad märgatavalt elektrokatalüütilist aktiivsust ja pikaaegset stabiilsust tugeva metall-katalüsaatorikandja vastastiktoime tõttu. Kõik selles töös uuritud materjalid näitasid märkimisväärset aktiivsust hapniku redutseerumisel ja paremat stabiilsust võrreldes kommertsiaalse 20% Pt/C katalüsaatoriga.
The aim of this study is to improve the electrocatalytic activity and lifetime of the platinum catalyst supported on carbon-based materials for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. Various methods were employed for the deposition of platinum nanoparticles on the support such as magnetron sputtering, electrochemical deposition, chemical synthesis and photo-deposition. Surface characterisation of the prepared electrocatalysts was performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) analysis, cyclic voltammetry and CO stripping experiments. The kinetics of the ORR has been thoroughly studied employing the rotating disk electrode (RDE) method. In the first part of the PhD studies, platinum nanoparticles were deposited on carbon-based support materials such as multi-walled carbon nanotubes and modified graphene nanosheets, the electrochemical measurements were carried out in both alkaline and acidic solutions. The second part of the research was devoted to investigate the activity and durability of platinum nanoparticles supported on metal oxide-carbon composites. Electrochemical results revealed that incorporating metal oxide (TiO2 or SnO2) into the carbon-based support materials increases the electrocatalytic activity and durability of the catalysts by the strong metal-support interaction. All the different types of electrocatalysts prepared and investigated in this work showed remarkable ORR activity and better long-term durability than that of the commercially available 20 wt.% Pt/C catalyst.
The aim of this study is to improve the electrocatalytic activity and lifetime of the platinum catalyst supported on carbon-based materials for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. Various methods were employed for the deposition of platinum nanoparticles on the support such as magnetron sputtering, electrochemical deposition, chemical synthesis and photo-deposition. Surface characterisation of the prepared electrocatalysts was performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) analysis, cyclic voltammetry and CO stripping experiments. The kinetics of the ORR has been thoroughly studied employing the rotating disk electrode (RDE) method. In the first part of the PhD studies, platinum nanoparticles were deposited on carbon-based support materials such as multi-walled carbon nanotubes and modified graphene nanosheets, the electrochemical measurements were carried out in both alkaline and acidic solutions. The second part of the research was devoted to investigate the activity and durability of platinum nanoparticles supported on metal oxide-carbon composites. Electrochemical results revealed that incorporating metal oxide (TiO2 or SnO2) into the carbon-based support materials increases the electrocatalytic activity and durability of the catalysts by the strong metal-support interaction. All the different types of electrocatalysts prepared and investigated in this work showed remarkable ORR activity and better long-term durability than that of the commercially available 20 wt.% Pt/C catalyst.
Description
Väitekirja elektrooniline versioon ei sisalda publikatsioone
Keywords
hapnik, elektrokeemiline reduktsioon, katalüsaatorid, plaatina, sadestamine, süsinikmaterjalid, metalloksiidid, nanomaterjalid