Karakterizacija žrtvujućih sredstava s in situ generiranim slobodnim kisikovim radikalima i njihova primjena kod fotoelektrokemijskog dobivanja vodika

master's thesis

• Title (english): Characterisation of sacrificial agents by in situ generated oxygen free radicals and its application in photoelectrochemical hydrogen production
• Author: Marija Lovrić
• Mentor: Marijana Kraljić Roković (mentor)
• Mentor: Dijana Jadreško (komentor)
• Committee member: Marijana Kraljić Roković (predsjednik povjerenstva)
• Committee member: Dijana Jadreško (član povjerenstva)
• Committee member: Dajana Mikić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2024-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Cilj ovog rada bio je provesti proces fotoelektrokemijskog dobivanja vodika pri tome ispitujući svojstva SnS2 elektrode uz dodatak različitih žrtvujućih sredstava. Korištene su različite koncentracije 5-aminosalicilne kiseline (5-ASK) bez prisustva i s prisustvom askorbinske kiseline (AA) u 0,1 M otopini NaCl kao osnovnom elektrolitu. Ispitivanja su provedena sljedećim metodama: linearna polarizacija, ciklička voltametrija, elektrokemijska impedancijska spektroskopija i kronoamperometrija za neosvijetljenu i osvijetljenu elektrodu. Mjerenja su provedena kroz tri ciklusa. S obzirom da SnS2 elektroda apsorbira u vidljivom dijelu spektra, kao izvor svjetla korištena je LED lampa. Za dodatnu karakterizaciju žrtvujućih sredstava ispitana su njihova antioksidativnih svojstava prema O2-‧ radikalu. Fotostruje zabilježene metodom linearne polarizacije potvrdile su dobru fotoaktivnost SnS2 u prisustvu žrtvujućih sredstava.. Također, metodom linearne polarizacije i kronoameprometrije pokazano je kako se najveći iznos struje dobiva kod prvog mjerenja, dok kod ostalih mjerenja imamo niže iznose struja zbog fotokorozije aktivnog materijala. U usporedbi struja za čistu 5-ASK i kombinaciju 5-ASK i AA može se zaključiti kako se njihovom kombinacijom dobivaju veći iznosi struje. Ovaj rezultat istraživanja je bitan jer se u prirodi najčešće pojavljuju kombinacije žrtvujućih sredstava pa je ključno ispitati njihovo međudjelovanje. Impedancijska mjerenja pokazuju kako je impedancija manja za osvijetljene elektrode, tj. manji je otpor prijelazu naboja nego za neosvijetljene elektrode što također potvrđuje dobru fotoaktivnost elektrode. Antioksidativna svojstva su ispitana metodom cikličke voltametrije koja ukazuje da će povećanje koncentracija 5-ASK u smjesi 5-ASK i AA doprinijeti boljem suzbijanju superoksidnog radikala.

Abstract (english)

The aim of this work was to carry out the process of photoelectrochemical production of hydrogen while examining the properties of the SnS2 electrode with the addition of various hole scavengers. Different concentrations of 5-aminosalicylic acid and ascorbic acid were used in 0.1 M NaCl solution as the basic electrolyte. Measurements were performed using the following methods: linear polarization, cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry for unilluminated and illuminated electrodes. Measurements were performed through three cycles. Given that the SnS2 electrode absorbs in the visible part of the spectrum, an LED lamp was used as a light source. As an additional characterization of the sacrificial agents, measurements were carried out to investigate the antioxidant properties against the O2-‧ radical. The results obtained by the linear polarization method indicate the photoactivity of the material due to the appearance of photocurrents for the illuminated electrodes. Also, using the method of linear polarization and chronoamperometry, it was shown that the highest amount of current is obtained in the first measurement, while in other measurements we have lower amounts of current due to photocorrosion of the active material. In comparing the currents for pure 5-ASK and the combination of 5-ASK and AA, it can be concluded that their combination results in higher amounts of current. This research result is important because combinations of sacrificial agents often appear in nature, so it was important to examine their interaction. Impedance measurements show that the impedance is lower for the illuminated electrodes, i.e. the charge transfer resistance is lower than for the non-illuminated electrodes, which confirms the good photoactivity of the electrode. The antioxidant properties were tested using the method of cyclic voltammetry, which indicates that increasing the concentration of 5-ASK in the solution of 5-ASK and AA will contribute to a better quenching of the superoxide radical.

• Keywords: fotoelektrokemijski proces; kositrov (IV) sulfid; žrtvujuća sredstva; antioksidativna svojstva; askorbinska kiselina; 5-aminosalicilna kiselina
• Keywords (english): photoelectrochemical process; tin (IV) sulfide; hole scavengers; antioxidant properties; ascorbic acid; 5-aminosalicylic acid
• Language: croatian
• URN:NBN: urn:nbn:hr:149:094519
• Project: Number: IP-2018-01-1982; Title: Nano-katalizatori aktivirani Sunčevim zračenjem u tehnologijama zaštite okoliša; Title: Nano-sized solar-active catalysts for environmental technologies; Acronym: NaSCEnT; Leader: Hrvoje Kušić; Jurisdiction: Croatia; Funder: Hrvatska zaklada za znanost; Funding stream: Research Projects
• Project: Number: KK.01.1.1.04.0001; Title: Pročišćavanje vode i dobivanje energije korištenjem novih kompozitnih materijala uz Sunčevo zračenje; Title: -; Leader: Hrvoje Kušić; Jurisdiction: eu; Funder: Europska unija; Funding stream: European Regional Development Fund
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2025-09-01
• Created on: 2024-11-11 09:34:32