Utjecaj iona kroma(III) na sintezu i svojstva nanostrukturiranih željezovih oksida

doctoral thesis

• Title (english): The influence of chromium(III) ions on the synthesis and properties of nanostructured iron oxides
• Author: Marko Robić
• Mentor: Svetozar Musić (mentor)
• Mentor: Stjepko Krehula (mentor)
• Committee member: Sanda Rončević (predsjednik povjerenstva)
• Committee member: Mirta Rubčić (član povjerenstva)
• Committee member: Andreja Gajović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2023-11-23, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

U ovom doktorskom radu istraženo je dopiranje hematita (α-Fe2O3) kromom(III) pomoću
metode elektroispredanja. Dopiranje uzoraka hematita ionima Cr3+ značajno se odrazilo na
strukturna, magnetska i druga svojstva. Osim toga, pokazano je kako se urotropin može koristiti
kao aditiv u hidrotermalnoj sintezi za taloženje oksida iz otopina FeCl3 i CrCl3 jer se pri
uvjetima sinteze raspada na amonijak, čime se podiže pH reakcijske smjese. Sintetizirani su
uzorci hematita dopirani s 10 % kroma(III) te su zapažene čestice hibridne morfologije koje se
sastoje od elipsoidnog i štapićastog dijela. Urotropin je također iskorišten za taloženje
oksihidroksida iz CrCl3 otopine, pri čemu je dobiven grimaldit (α-CrOOH). Žarenjem
grimaldita koji je istaložio uz dodatak urotropina nastaje eskolait (α-Cr2O3) koji se sastoji od
vrlo sitnih nanočestica. Autoklaviranjem reakcijskih smjesa koje su sadržavale množinski udio
kroma(III) od 50 % dobivene su dendritne morfologije kompozitnog sastava koje sadrže Cr3+ u
svojoj strukturi. U ovom doktorskom radu ispitan je i utjecaj iona kroma(III) na precipitaciju
željezovih oksida iz otopina priređenih otapanjem FeCl3. Zapaženo je da nastale čestice
hematita zbog prisutnosti iona kroma(III) poprimaju elipsoidni oblik.

Abstract (english)

In this dissertation, the doping of hematite (α-Fe2O3) with chromium(III) was investigated using
the electrospinning method. The doping of hematite samples with Cr3+ ions significantly
influenced the structural, magnetic and other properties. It was also shown that urotropin can
be used as an additive in hydrothermal synthesis for the precipitation of oxides from FeCl3 and
CrCl3 solutions, as it decomposes into ammonia under the synthesis conditions, which raises
the pH of the reaction mixture. Samples of hematite doped with 10% chromium(III) were
synthesised and particles with a hybrid morphology consisting of an ellipsoidal and a rod-like
part were observed. Urotropin was also used to precipitate the oxyhydroxide from a CrCl3
solution, obtaining grimaldite (α-CrOOH). Escolaite (α-Cr2O3), which consists of very small
nanoparticles, is formed by annealing the precipitated grimaldite. By autoclaving reaction
mixtures containing a molar fraction of chromium(III) of 50%, dendritic morphologies of
composite compositions containing Cr3+ in their structure were obtained. In this dissertation,
the influence of chromium(III) on the precipitation of iron oxides from solutions prepared by
dissolving FeCl3 was investigated. It was observed that the resulting hematite particles take an
ellipsoidal shape due to the presence of chromium(III) ions.

• Keywords: elektroispredanje; fotokataliza; hematit; Mössbauerova spektroskopija; nanostrukture; ubrzana hidroliza; željezovi oksidI
• Keywords (english): electrospinning; forced hydrolysis; hematite; iron oxides; Mössbauer spectroscopy; nanostructures; photocatalysis
• Language: croatian
• URN:NBN: urn:nbn:hr:217:589542
• Promotion: 2023
• 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: Doctoral study; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica u području prirodnih znanosti (doktor/doktorica u području prirodnih znanosti)
• Type of resource: Text
• Extent: XV, 181 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-12-18 12:16:37