(Mikro)strukturna i elektrokemijska karakterizacija kompozita rGO/V2O5

master's thesis

• Title (english): (Micro)structural and electrochemical characterization of rGO/V2O5 composite
• Author: Dora Lovrenčić
• Mentor: Marijana Kraljić Roković (mentor)
• Mentor: Sanja Burazer (komentor)
• Committee member: Marijana Kraljić Roković (predsjednik povjerenstva)
• Committee member: Helena Otmačić Ćurković (član povjerenstva)
• Committee member: Sanja Burazer (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2024-07-10, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

U ovom je radu priređen papir grafenova oksida te papir grafenova oksida s dodatkom 70 % V2O5 primjenom metode vakuumske filtracije, nakon čega je provedena redukcija metodom kronoamperometrije čime je priređen rGO i kompozit rGO/V2O5. Kako je za sve primjene od iznimne važnosti povezati strukturu sa svojstvima, ovim je radom pokrivena detaljna strukturna i mikrostrukturna karakterizacija V2O5 te njegovog kompozita rGO/V2O5. Provedena su ispitivanja termičke stabilnosti strukture i ekspanzije materijala, veličine kristalita i svih strukturnih promjena i prijelaza u različite kristalne faze. Zbog izvrsnih karakteristika V2O5 i njegovih kompozita, koje su dokazane u dosadašnjoj primjeni ovog materijala u elektrokemijskim uređajima, u ovom radu su metodama cikličke voltametrije i kronopotenciomerije proučena elektrokemijska svojstva kompozita rGO/V2O5 sa stajališta primjene u baterijskim sustavima. Osim u elektrokemijskim spremnicima energije, V2O5 i njegovi kompoziti s reduciranim grafenovim oksidom poznati su i po upotrebi za fotokatalitičko dobivanje vodika, zbog čega su i u ovom radu provedena ispitivanja fotokatalitičke aktivnosti s bojilima rodamin B (RhB) i metilen plavo (MB). Rezultati su pokazali da je korišteni V2O5 materijal s vrlo malom termičkom ekspanzijom i kristalitima nanometarskih veličina te je pogodan za pripravu nanokompozita. U ovom je radu uspješno priređen kompozit rGO/V2O5 što je potvrđeno rendgenskom difrakcijom, SEM i EDS te mikroskopijom s grijaćom pločom. Priređeni kompozit je izvrstan fotokatalizator koji je razgradio 94,3 % MB bojila visoke koncentracije (25 ppm) nakon 120 min. Baterija priređena s ispitivanim kompozitom pokazala je visoke kapacitete, a detaljna ispitivanja kod različitih brzina ukazala su da je brzina reakcije kontrolirana interkalacijskim procesima.

Abstract (english)

In this work, pure graphene oxide paper and one with the addition of 70 % V2O5 were prepared using the vacuum filtration method. Afterwards, the reduction was carried out using the chronoamperometry method, resulting in prepared rGO and the rGO/V2O5 composite. Structure-properties relationship is of an extreme importance for all applications, therefore this work covers the detailed structural and microstructural characterization of V2O5 and its rGO/V2O5 composite. The thermal stability of the structure and the expansion of the material, as well as the size of the crystallites and all structural changes and transitions into different crystalline phases were investigated. Due to the excellent characteristics of V2O5 and its composites, that have been proven in the previous application of this material in electrochemical devices, in this work, the electrochemical properties of rGO/V2O5 composite were studied using the methods of cyclic voltammetry and chronopotentiometry from the point of view of application in battery systems. In addition to electrochemical energy storage, V2O5 and its composites with reduced graphene oxide are also known for their use in photocatalytic production of hydrogen, and that is why in this work tests of photocatalytic activity with the dyes rhodamine B (RhB) and methylene blue (MB) were carried out. The results showed that the used V2O5 material has very low thermal expansion and nanocrystallites, therefore it is suitable for the preparation of nanocomposites. In this work, rGO/V2O5 composite was successfully prepared, which was confirmed by X-ray diffraction, SEM and EDS, and hot-stage microscopy. The prepared composite is an excellent photocatalyst that decomposed 94.3 % of high-concentration MB dyes (25 ppm) after
120 min. The battery prepared with the tested composite showed high capacities, and detailed tests at different speeds indicated that the reaction speed was controlled by intercalation processes.

• Keywords: baterija; elektrokemijska karakterizacija; fotokatalitička aktivnost; kompozit rGO/V2O5; morfološka karakterizacija; rendgenska difrakcija u polikristalu
• Keywords (english): battery; electrochemical characterization; photocatalytic activity; composite rGO/V2O5; morphologic characterization; X-ray powder diffraction
• Language: croatian
• URN:NBN: urn:nbn:hr:149:632656
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Advanced materials and technologies; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra primijenjene kemije (sveučilišni/a magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2025-07-01
• Created on: 2024-07-15 12:35:28