{"id":{"repo_id":"tartu","oai_identifier":"oai:dspace.ut.ee:10062/123413"},"canonical_url":"https://search.dev.ndltd.org/etd/tartu/oai:dspace.ut.ee:10062/123413","repository":{"repo_id":"tartu","name":"University of Tartu","base_url":"http://dspace.ut.ee/oai/request"},"display":{"title":"Electrocatalysis of oxygen reduction on Pt nanoparticles deposited on novel support materials","abstract":"Selle doktoritöö eesmärk oli uurida süsinikkandja mõju plaatina nanoosakeste elektrokatalüütilisele aktiivsusele hapniku redutseerumisreaktsioonis happelises lahuses ja prootonivahetusmembraaniga kütuseelementides. Töös kasutati erinevalt funktsionaliseeritud süsinikmaterjale plaatina nanoosakeste kandjana, kusjuures Pt sadestati kas keemiliselt või elektrokeemiliselt. Valmistatud katalüsaatormaterjale karakteriseeriti lämmastiku adsorptsiooni/desorptsiooni isotermide, röntgenfotoelektronspektroskoopia, skaneeriva elektronmikroskoopia ja läbistuselektronmikroskoopia, röntgenfluorestsentsspektroskoopia ja Ramani spektroskoopia abil. Elektrokeemiliseks karakteriseerimiseks kasutati tsüklilist voltamperomeetriat, eeladsorbeeritud CO oksüdeerimist, pöörleva ketaselektroodi meetodit ja üherakulist kütuseelementi. Töö esimeses osas sadestati Pt nanoosakesed kommertsiaalselt kättesaadavatele heteroaatomitega dopeeritud grafeeniliistakutele. Tuvastati, et ühe heteroaatomiga dopeeritud grafeenile sadestatud Pt nanoosakesed olid aktiivsemad kui mitme heteroaatomiga dopeeritud grafeenile sadestatud. Töö teises osas täheldati vastupidist trendi, kui samadele grafeeniliistakutele sadestati Pt keemilise sünteesiprotseduuri abil. Töö kolmandas osas sadestati Pt lämmastikuga dopeeritud poorsele süsinikule. Leiti, et süsinikmaterjali lisamise tingimused katalüsaatori valmistamisel on olulise tähtsusega, kuna sellest sõltuvad nii elektrokatalüütiline aktiivsus kui ka kütuseelemendi jõudlus. Töö viimases osas sadestati Pt nanoosakesed SnO2-ga kaetud süsiniknanotorudele. Tina(IV)oksiidi lisamine suurendas katalüsaatori stabiilsust, ületades kommertsiaalse Pt/C stabiilsuse. Käesolev töö näitab, et süsinikkandja optimeerimine on esmatähtis, kuna sellest sõltub valmistatava Pt/C katalüsaatori elektrokatalüütiline aktiivsus hapniku redutseerumiselThe aim of this thesis was to investigate the effects the carbon support material on the overall electrocatalytic activity of Pt nanoparticles (PtNPs) for the oxygen reduction reaction (ORR) in acid media and in proton exchange membrane fuel cells (PEMFCs). Different functionalized carbon materials were used as supports for PtNPs, which were deposited onto the carbons using two different methods: chemical and electrochemical deposition. The synthesized catalysts were characterized by N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), X-ray fluorescence spectroscopy (XRF), and Raman spectroscopy. The electrochemical properties of the electrocatalysts were examined via cyclic voltammetry (CV), CO-stripping, the rotating disk electrode (RDE) method and single-cell PEMFC tests. In the first part of the PhD thesis, the PtNPs were electrochemically deposited onto different commercially available heteroatom-doped graphenes. There was a trend that the PtNPs electrochemically deposited onto single heteroatom-doped graphenes had a higher specific activity for ORR than those supported on dual heteroatom-doped graphenes. This was the opposite of what was found in the second part of the thesis, in which PtNPs were chemically deposited onto different heteroatom-doped graphenes. In the third part of this thesis, PtNPs were deposited onto nitrogen-doped porous carbon. In this study it was found that the chemical deposition method used had an influence on the electrocatalytic activity and PEMFC performance of the catalyst. In the final part of the thesis, PtNPs were chemically deposited onto SnO2-coated carbon nanotubes. This catalyst exhibited superior stability compared to the commercially available 20% Pt/C catalyst. The works presented in this study confirm that optimizing a carbon support is imperative, as it directly impacts the overall electrocatalytic activity of PtNPs for ORR.","abstract_html":"Selle doktoritöö eesmärk oli uurida süsinikkandja mõju plaatina nanoosakeste elektrokatalüütilisele aktiivsusele hapniku redutseerumisreaktsioonis happelises lahuses ja prootonivahetusmembraaniga kütuseelementides. Töös kasutati erinevalt funktsionaliseeritud süsinikmaterjale plaatina nanoosakeste kandjana, kusjuures Pt sadestati kas keemiliselt või elektrokeemiliselt. Valmistatud katalüsaatormaterjale karakteriseeriti lämmastiku adsorptsiooni/desorptsiooni isotermide, röntgenfotoelektronspektroskoopia, skaneeriva elektronmikroskoopia ja läbistuselektronmikroskoopia, röntgenfluorestsentsspektroskoopia ja Ramani spektroskoopia abil. Elektrokeemiliseks karakteriseerimiseks kasutati tsüklilist voltamperomeetriat, eeladsorbeeritud CO oksüdeerimist, pöörleva ketaselektroodi meetodit ja üherakulist kütuseelementi. Töö esimeses osas sadestati Pt nanoosakesed kommertsiaalselt kättesaadavatele heteroaatomitega dopeeritud grafeeniliistakutele. Tuvastati, et ühe heteroaatomiga dopeeritud grafeenile sadestatud Pt nanoosakesed olid aktiivsemad kui mitme heteroaatomiga dopeeritud grafeenile sadestatud. Töö teises osas täheldati vastupidist trendi, kui samadele grafeeniliistakutele sadestati Pt keemilise sünteesiprotseduuri abil. Töö kolmandas osas sadestati Pt lämmastikuga dopeeritud poorsele süsinikule. Leiti, et süsinikmaterjali lisamise tingimused katalüsaatori valmistamisel on olulise tähtsusega, kuna sellest sõltuvad nii elektrokatalüütiline aktiivsus kui ka kütuseelemendi jõudlus. Töö viimases osas sadestati Pt nanoosakesed SnO2-ga kaetud süsiniknanotorudele. Tina(IV)oksiidi lisamine suurendas katalüsaatori stabiilsust, ületades kommertsiaalse Pt/C stabiilsuse. Käesolev töö näitab, et süsinikkandja optimeerimine on esmatähtis, kuna sellest sõltub valmistatava Pt/C katalüsaatori elektrokatalüütiline aktiivsus hapniku redutseerumiselThe aim of this thesis was to investigate the effects the carbon support material on the overall electrocatalytic activity of Pt nanoparticles (PtNPs) for the oxygen reduction reaction (ORR) in acid media and in proton exchange membrane fuel cells (PEMFCs). Different functionalized carbon materials were used as supports for PtNPs, which were deposited onto the carbons using two different methods: chemical and electrochemical deposition. The synthesized catalysts were characterized by N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), X-ray fluorescence spectroscopy (XRF), and Raman spectroscopy. The electrochemical properties of the electrocatalysts were examined via cyclic voltammetry (CV), CO-stripping, the rotating disk electrode (RDE) method and single-cell PEMFC tests. In the first part of the PhD thesis, the PtNPs were electrochemically deposited onto different commercially available heteroatom-doped graphenes. There was a trend that the PtNPs electrochemically deposited onto single heteroatom-doped graphenes had a higher specific activity for ORR than those supported on dual heteroatom-doped graphenes. This was the opposite of what was found in the second part of the thesis, in which PtNPs were chemically deposited onto different heteroatom-doped graphenes. In the third part of this thesis, PtNPs were deposited onto nitrogen-doped porous carbon. In this study it was found that the chemical deposition method used had an influence on the electrocatalytic activity and PEMFC performance of the catalyst. In the final part of the thesis, PtNPs were chemically deposited onto SnO2-coated carbon nanotubes. This catalyst exhibited superior stability compared to the commercially available 20% Pt/C catalyst. The works presented in this study confirm that optimizing a carbon support is imperative, as it directly impacts the overall electrocatalytic activity of PtNPs for ORR.","abstract_has_math":false,"creators":["Chambers, Raegan Danielle"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-07-10","date_published":"2026-07-10","updated_at":"2026-07-24T06:23:48Z","subjects":["doktoritööd"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["hdl:10062/123413"],"render_values":[{"text":"hdl:10062/123413","href":null,"code":true}]}]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2026-07-10"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["doktoritööd"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["hdl:10062/123413"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.other","label":"Dc Description Other","values":["Selle doktoritöö eesmärk oli uurida süsinikkandja mõju plaatina nanoosakeste elektrokatalüütilisele aktiivsusele hapniku redutseerumisreaktsioonis happelises lahuses ja prootonivahetusmembraaniga kütuseelementides. Töös kasutati erinevalt funktsionaliseeritud süsinikmaterjale plaatina nanoosakeste kandjana, kusjuures Pt sadestati kas keemiliselt või elektrokeemiliselt. Valmistatud katalüsaatormaterjale karakteriseeriti lämmastiku adsorptsiooni/desorptsiooni isotermide, röntgenfotoelektronspektroskoopia, skaneeriva elektronmikroskoopia ja läbistuselektronmikroskoopia, röntgenfluorestsentsspektroskoopia ja Ramani spektroskoopia abil. Elektrokeemiliseks karakteriseerimiseks kasutati tsüklilist voltamperomeetriat, eeladsorbeeritud CO oksüdeerimist, pöörleva ketaselektroodi meetodit ja üherakulist kütuseelementi. Töö esimeses osas sadestati Pt nanoosakesed kommertsiaalselt kättesaadavatele heteroaatomitega dopeeritud grafeeniliistakutele. Tuvastati, et ühe heteroaatomiga dopeeritud grafeenile sadestatud Pt nanoosakesed olid aktiivsemad kui mitme heteroaatomiga dopeeritud grafeenile sadestatud. Töö teises osas täheldati vastupidist trendi, kui samadele grafeeniliistakutele sadestati Pt keemilise sünteesiprotseduuri abil. Töö kolmandas osas sadestati Pt lämmastikuga dopeeritud poorsele süsinikule. Leiti, et süsinikmaterjali lisamise tingimused katalüsaatori valmistamisel on olulise tähtsusega, kuna sellest sõltuvad nii elektrokatalüütiline aktiivsus kui ka kütuseelemendi jõudlus. Töö viimases osas sadestati Pt nanoosakesed SnO2-ga kaetud süsiniknanotorudele. Tina(IV)oksiidi lisamine suurendas katalüsaatori stabiilsust, ületades kommertsiaalse Pt/C stabiilsuse. Käesolev töö näitab, et süsinikkandja optimeerimine on esmatähtis, kuna sellest sõltub valmistatava Pt/C katalüsaatori elektrokatalüütiline aktiivsus hapniku redutseerumiselThe aim of this thesis was to investigate the effects the carbon support material on the overall electrocatalytic activity of Pt nanoparticles (PtNPs) for the oxygen reduction reaction (ORR) in acid media and in proton exchange membrane fuel cells (PEMFCs). Different functionalized carbon materials were used as supports for PtNPs, which were deposited onto the carbons using two different methods: chemical and electrochemical deposition. The synthesized catalysts were characterized by N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), X-ray fluorescence spectroscopy (XRF), and Raman spectroscopy. The electrochemical properties of the electrocatalysts were examined via cyclic voltammetry (CV), CO-stripping, the rotating disk electrode (RDE) method and single-cell PEMFC tests. In the first part of the PhD thesis, the PtNPs were electrochemically deposited onto different commercially available heteroatom-doped graphenes. There was a trend that the PtNPs electrochemically deposited onto single heteroatom-doped graphenes had a higher specific activity for ORR than those supported on dual heteroatom-doped graphenes. This was the opposite of what was found in the second part of the thesis, in which PtNPs were chemically deposited onto different heteroatom-doped graphenes. In the third part of this thesis, PtNPs were deposited onto nitrogen-doped porous carbon. In this study it was found that the chemical deposition method used had an influence on the electrocatalytic activity and PEMFC performance of the catalyst. In the final part of the thesis, PtNPs were chemically deposited onto SnO2-coated carbon nanotubes. This catalyst exhibited superior stability compared to the commercially available 20% Pt/C catalyst. The works presented in this study confirm that optimizing a carbon support is imperative, as it directly impacts the overall electrocatalytic activity of PtNPs for ORR."]},{"key":"dc:title","label":"Title","values":["Electrocatalysis of oxygen reduction on Pt nanoparticles deposited on novel support materials"]}]}],"canonical_facts":{"dc:date.issued":["2026-07-10"],"dc:description.other":["Selle doktoritöö eesmärk oli uurida süsinikkandja mõju plaatina nanoosakeste elektrokatalüütilisele aktiivsusele hapniku redutseerumisreaktsioonis happelises lahuses ja prootonivahetusmembraaniga kütuseelementides. Töös kasutati erinevalt funktsionaliseeritud süsinikmaterjale plaatina nanoosakeste kandjana, kusjuures Pt sadestati kas keemiliselt või elektrokeemiliselt. Valmistatud katalüsaatormaterjale karakteriseeriti lämmastiku adsorptsiooni/desorptsiooni isotermide, röntgenfotoelektronspektroskoopia, skaneeriva elektronmikroskoopia ja läbistuselektronmikroskoopia, röntgenfluorestsentsspektroskoopia ja Ramani spektroskoopia abil. Elektrokeemiliseks karakteriseerimiseks kasutati tsüklilist voltamperomeetriat, eeladsorbeeritud CO oksüdeerimist, pöörleva ketaselektroodi meetodit ja üherakulist kütuseelementi. Töö esimeses osas sadestati Pt nanoosakesed kommertsiaalselt kättesaadavatele heteroaatomitega dopeeritud grafeeniliistakutele. Tuvastati, et ühe heteroaatomiga dopeeritud grafeenile sadestatud Pt nanoosakesed olid aktiivsemad kui mitme heteroaatomiga dopeeritud grafeenile sadestatud. Töö teises osas täheldati vastupidist trendi, kui samadele grafeeniliistakutele sadestati Pt keemilise sünteesiprotseduuri abil. Töö kolmandas osas sadestati Pt lämmastikuga dopeeritud poorsele süsinikule. Leiti, et süsinikmaterjali lisamise tingimused katalüsaatori valmistamisel on olulise tähtsusega, kuna sellest sõltuvad nii elektrokatalüütiline aktiivsus kui ka kütuseelemendi jõudlus. Töö viimases osas sadestati Pt nanoosakesed SnO2-ga kaetud süsiniknanotorudele. Tina(IV)oksiidi lisamine suurendas katalüsaatori stabiilsust, ületades kommertsiaalse Pt/C stabiilsuse. Käesolev töö näitab, et süsinikkandja optimeerimine on esmatähtis, kuna sellest sõltub valmistatava Pt/C katalüsaatori elektrokatalüütiline aktiivsus hapniku redutseerumiselThe aim of this thesis was to investigate the effects the carbon support material on the overall electrocatalytic activity of Pt nanoparticles (PtNPs) for the oxygen reduction reaction (ORR) in acid media and in proton exchange membrane fuel cells (PEMFCs). Different functionalized carbon materials were used as supports for PtNPs, which were deposited onto the carbons using two different methods: chemical and electrochemical deposition. The synthesized catalysts were characterized by N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), X-ray fluorescence spectroscopy (XRF), and Raman spectroscopy. The electrochemical properties of the electrocatalysts were examined via cyclic voltammetry (CV), CO-stripping, the rotating disk electrode (RDE) method and single-cell PEMFC tests. In the first part of the PhD thesis, the PtNPs were electrochemically deposited onto different commercially available heteroatom-doped graphenes. There was a trend that the PtNPs electrochemically deposited onto single heteroatom-doped graphenes had a higher specific activity for ORR than those supported on dual heteroatom-doped graphenes. This was the opposite of what was found in the second part of the thesis, in which PtNPs were chemically deposited onto different heteroatom-doped graphenes. In the third part of this thesis, PtNPs were deposited onto nitrogen-doped porous carbon. In this study it was found that the chemical deposition method used had an influence on the electrocatalytic activity and PEMFC performance of the catalyst. In the final part of the thesis, PtNPs were chemically deposited onto SnO2-coated carbon nanotubes. This catalyst exhibited superior stability compared to the commercially available 20% Pt/C catalyst. The works presented in this study confirm that optimizing a carbon support is imperative, as it directly impacts the overall electrocatalytic activity of PtNPs for ORR."],"dc:identifier":["hdl:10062/123413"],"dc:subject":["doktoritööd"],"dc:title":["Electrocatalysis of oxygen reduction on Pt nanoparticles deposited on novel support materials"],"dc:type":["Thesis"]},"updated_at":"2026-07-24T06:23:48Z"}