Uporaba z dušikom dopiranih grafenskih derivatov v napravah za pretvorbo energije

Nosan, Miha (avtor), Genorio, Boštjan (mentor)

Nanomateriali na osnovi ogljika, predvsem z dubikom dopirani grafenski derivati (GD), predstavljajo obetavno in cenovno učinkovito alternativo za uporabo v gorivnih celicah s protonsko izmenjevalno membrano (PEMFC). Slednji bi lahko zamenjali drage katalizatorje na osnovi plemenitih kovin, ki se trenutno uporabljajo za katalizo katodne reakcije redukcije kisika (ORR). V doktorski disertaciji obravnavamo različne sinteze metode skupaj z morfološko, kemijsko in elektrokemijsko karakterizacijo termično obdelanih derivatov grafen oksida (htGOD) ter z dušikom dopiranih derivatov grafen oksida (N-htGOD). Proučili smo vpliv N-dopiranja, kovinskih nečistot, razmerje stranic med 2D (grafen) in kvazi-1D (nanotrakovi) dimenzionalnostmi, specifične BET površine (S$_{BET}$) in konfiguracije dušika na elektrokatalitsko učinkovitost ORR. Pri optimizaciji S$_{BET}$ za elektrokatalitsko učinkovitost ORR smo prav tako postavili metodo segrevanja na osnovi indukcije. Rezultate omenjenih vplivov smo nato uporabili pri sintezi N-htGOD z najboljšo elektrokatalitsko aktivnostjo ORR in ga testirali v realnem sistemu PEMFC. Sočasno smo proučili tudi selektivnost ORR N-htGOD in htGOD za elektrokemijsko proizvodnjo vodikovega peroksida (H$_2$O$_2$). Sintetizirani materiali, zlasti z Ni dekorirani materiali na osnovi termično obdelanega grafen oksida (Ni@htGO), so pokazali visoko učinkovitost proizvodnje H$_2$O$_2$. Glavni vpliv na selektivnost ORR so imele konfiguracije Ni, ki smo jih primerjali s sintezo Ni@htGO pri različnih končnih temperaturah. Rezultati raziskave nudijo vpogled v sintezo, modifikacijo, optimizacijo in delovanje brez kovinskih in kovinskih N-htGOD elektrokatalizatorjev za učinkovito aplikacijo v PEMFC ali proizvodnji H$_2$O$_2$.

• Jezik: Slovenski jezik
• Ključne besede: N-dopirani grafenski derivati, reakcija redukcije kisika, gorivne celice s protonsko izmenjevalno membrano, proizvodnja vodikovega peroksida, kovinske nečistote
• Vrsta gradiva: Doktorsko delo/naloga
• Tipologija: 2.08 - Doktorska disertacija
• Organizacija: FKKT - Fakulteta za kemijo in kemijsko tehnologijo
• Leto izida: 2024
• PID: 20.500.12556/RUL-164749
• COBISS.SI-ID: 218517251
• Datum objave v RUL: 08.11.2024

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: The use of nitrogen doped graphene derivatives for energy conversion devices

Izvleček

Carbon-based nanomaterials, particularly N-doped graphene derivatives, offer a viable and economical alternative to noble metal catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). This research addresses different synthesis methods and provides in-depth morphological, chemical and electrochemical analysis of various heat-treated graphene and N-doped graphene oxide derivatives, focusing on N-doped graphene oxide (N-htGO) and N-doped graphene oxide nanoribbons (N-htGONR). Work focuses on the investigation, validation, and comparison of factors influencing the ORR performance. Such as the pH dependent effect of inherent metal impurities, the aspect ratio contrast between 2D graphene and quasi-1D nanoribbons dimensions, considerations, improved surface area, and the influence of N-configuration on ORR activity. Based on results, the most promising properties are comprehensively integrated into N-doped graphene derivatives (N-GOD) and evaluated in a PEMFC for ORR. Pushing the boundaries of carbon-based materials research, we introduce an innovative, scalable method of electrical induction heat treatment. This innovative approach not only accelerates the reaction process, but also enhances the energy efficiency and ORR performance of N-GOD in acidic and alkaline media. At the same time, we investigated the potential of N-GOD and undoped GOD for green electrochemical conversion of ORR to hydrogen peroxide (H$_2$O$_2$), a sustainable alternative to the traditional anthraquinone autooxidation method. In particular, Ni-based heat-treated graphene oxide (Ni@htGO) materials showed remarkable ORR selectivity. To additionally improve the efficacy of Ni@htGO, we investigated various temperature-controlled synthesis routes with different nickel configurations, revealing a link between Ni functions and H$_2$O$_2$ production. In summary, this comprehensive study sheds light on the synthesis, characterization, optimization, and efficacy of non-metallic N-htGOD electrocatalysts, either for H$_2$O$_2$ production or PEMFCs applications.

• Ključne besede: N-doped graphene derivatives, oxygen reduction reaction, proton-exchange membrane fuel cells, hydrogen peroxide production, metal impurities