Određivanje nestehiometrije kisika u perovskitima permanganatnom titracijom

undergraduate thesis

• Title (english): Determination of oxygen nonstoichiometry in perovskites by permanganate titration
• Author: Valentina Jakopović
• Mentor: Jelena Macan (mentor)
• Committee member: Jelena Macan (predsjednik povjerenstva)
• Committee member: Ana Vrsalović Presečki (član povjerenstva)
• Committee member: Krunoslav Žižek (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-09-06, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Za potpunu karakterizaciju manganovih perovskita, manganita, vrlo je važan parametar nestehiometrija kisika. Nestehiometrija kisika direktno je povezana s omjerom Mn3+/Mn4+ koji utječe na svojstva manganita. Perovskiti bogati kisikom imaju izraženija magnetska svojstva pri sobnoj temperaturi, dok kod onih s deficitom kisika prevladavaju električna svojstva. Postoji nekoliko metoda kojima je moguće odrediti nestehiometriju kisika u perovskitima, kao što su termogravimetrijska analiza (TGA) i volumetrijske metode (titracije). Cilj ovog rada bio je ispitati primjenjivost metode permanganatne titracije uz Mohrovu sol na određivanje nestehiometrije kisika u manganitima. Postupkom titracije određen je sadržaj kisika u uzorcima La1-xSrxMnO3 pripremljenima limunskim (x = 0, 0,1, 0,2 i 0,3) i koprecipitacijskim (x = 0, 0,1, 0,2, 0,3 i 0,5) postupkom sinteze. Utvrđeno je da je metoda permanganatne titracije primjenjiva na određivanje nestehiometrije kisika u manganitima te da ju je moguće jednostavno, brzo i ponovljivo primjenjivati. Osim toga, rezultati su pokazali da je koprecipitacijskim postupkom sinteze moguće proizvesti uzorke s izraženijom nestehiometrijom kisika za primjene u kojima je potrebna velika električna provodnost materijala.

Abstract (english)

The oxygen nonstoichiometry parameter is very important for the complete characterization of manganese perovskites, manganites. Oxygen nonstoichiometry is directly related to the Mn3+/Mn4+ ratio, which in turn affects the properties of manganites. Perovskites rich in oxygen have more pronounced magnetic properties at room temperature, while those with oxygen deficiency have predominant electrical properties. There are several methods by which it is possible to determine oxygen nonstoichiometry in perovskites, such as thermogravimetric analysis (TGA) and volumetric methods (titrations). The aim of this study was to examine the applicability of the permanganate titration method with Mohr's salt for the determination of oxygen nonstoichiometry in manganites. The amount of oxygen in La1-xSrxMnO3 samples prepared by citric (x = 0, 0.1, 0.2 and 0.3) and co-precipitation (x = 0, 0.1, 0.2, 0.3 and 0.5) synthesis procedure was determined by permanganate titration. It was observed that the permanganate titration method is applicable on the oxygen nonstoichiometry determination in perovskites and that it is simple, fast and reproducible. Furthermore, the obtained results have shown that it is possible to prepare samples with high oxygen nonstoichiometry by co-precipitation procedure for applications which are requiring high electrical conductivity of the material.

• Keywords: Mohrova sol; nestehiometrija kisika; permanganatna titracija; perovskiti
• Keywords (english): Mohr's salt; oxygen nonstoichiometry; permanganate titration; perovskite
• Language: croatian
• URN:NBN: urn:nbn:hr:149:389112
• Project: Number: IP-2018-01-5246; Title: Nanokompoziti s perovskitima za fotovoltaike, fotokatalizu i senzoriku; Acronym: NanoPeroPhotoSens; Leader: Andreja Gajović; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Chemical Engineering - Undergraduate study; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-04-04 07:23:56