Fotokatalitička svojstva nanostruktura oksida željeza

master's thesis

• Title (english): Photocatalytic properties of iron oxide nanostructures
• Author: Tin Takač
• Mentor: Jozefina Katić (mentor)
• Mentor: Željka Petrović (komentor)
• Committee member: Marijana Kraljić Roković (predsjednik povjerenstva)
• Committee member: Stanislav Kurajica (član povjerenstva)
• Committee member: Željka Petrović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-09-17, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Hematit (α-Fe2O3) se zbog svojih karakteristika poput male vrijednosti energijskog procijepa (oko 2.1 eV), izuzetne stabilnosti, netoksičnosti i niske cijene, intenzivno istražuje kao fotokatalizator i materijal za izradu fotoanoda. Međutim, njegov veliki nedostatak je loša električna vodljivost koju treba povećati. Jedan od načina je dopiranje, odnosno ugradnja primjesa koje će zamijeniti osnovni atom (Fe3+) na njegovu mjestu u kristalnoj rešetki. U ovom radu metodom elektroispredanja provedena je sinteza 1D hematita u obliku vlakana bez i sa dodatkom 2 at. % i 5 at. % Ru3+ kao ekstrinsične primjese. Kako bi se utvrdio utjecaj Ru3+ dopanda na morfološka, strukturna, optička i poluvodička svojstva hematita, vlakana su karakterizirana sljedećim metodama: UV/Vis, ATR-FTIR, SEM, EDS i XRD. Prema rezultatima svih metoda, vlakna se dominantno sastoje od hematitne faze. Usporedbom ATR-FTIR spektara i difraktograma dopiranih i nedopiranih vlakana vidljiv je pomak vrpci (ATR-FTIR) i pomak maksimuma (XRD), što potvrđuje uspješnu ugradnju Ru3+ iona u strukturu hematita. Utjecaj dopiranja na optička i poluvodička svojstva hematita jasno je vidljiv i u smanjenoj vrijednosti energijskog procijepa dopiranih uzoraka [Ebg (5 at. % Ru3+) = 2,05 eV, direktni prijelaz] u odnosu na nedopirani uzorak (Ebg = 2,10 eV, direktni prijelaz) što ukazuje na povećanje električne vodljivosti dopiranih uzoraka. Materijal ovakvih karakteristika potencijalni je kandidat za primjenu u procesima pročišćavanja otpadnih voda kao fotokatalizator.

Abstract (english)

Hematite (α-Fe2O3) is being intensively investigated for use as a photocatalyst and photoanode material due to its properties such as low energy gap value (about 2.1 eV), exceptional stability, nontoxicity, and low cost. However, its major drawback is poor electrical conductivity, which needs to be enhanced. One of the ways is doping, which is the incorporation of impurities to replace the base atom (Fe3+) in its place in the crystal lattice. In this work, the synthesis of 1D hematite in the form of fibers was carried out by electrospinning method, without and with the addition of 2 at. % and 5 at. % Ru3+ as extrinsic impurities. To determine the effect of Ru3+ doping on the morphological, structural, optical, and semiconducting properties of hematite, the fibers were characterized by the following methods: UV/Vis, ATR-FTIR, SEM, EDS, and XRD. According to the results of all methods, the fibers are predominantly composed of the hematite phase. Comparison of ATR-FTIR spectra and diffractograms of doped and undoped fibers shows a band shift (ATR-FTIR) and a maximum shift (XRD), confirming the successful incorporation of Ru3+ ions into the hematite structure. The influence of doping on the optical and semiconducting properties of hematite is reflected in the reduced value of the energy gap of the doped samples [Ebg (5% at. Ru3+) = 2.05 eV, direct transition] to the undoped sample (Ebg = 2.10 eV, direct transition), indicating an increase in the electrical conductivity of the doped samples. Material with such properties is a potential candidate for application in wastewater treatment processes as a photocatalyst.

• Keywords: elektroispredanje; hematit; dopiranje; rutenijev(III) kation; energijski procijep; fotokatalitička svojstva
• Keywords (english): electrospinning; hematite; doping; ruthenium(III) cation; band gap; photocatalytic properties
• Language: croatian
• URN:NBN: urn:nbn:hr:149:844759
• Project: Number: IP-2016-06-8254; Title: Nastajanje i svojstva 1D α-Fe2O3 nanostruktura dopiranih odabranim metalnim ionima; Title: Formation and properties of 1D α-Fe2O3 nanostructures doped with selected metal ions; Acronym: 1D-DopedFeOX; Leader: Stjepko Krehula; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2023-04-14 10:29:48