Priprava i karakterizacija kompozita MnO2/grafen za primjenu u superkondenzatorima

master's thesis

• Title (english): Preparation and characterisation of MnO2/graphene composites for supercapacitor application
• Author: Alen Lutvica
• Mentor: Marijana Kraljić Roković (mentor)
• Committee member: Marijana Kraljić Roković (predsjednik povjerenstva)
• Committee member: Zoran Mandić (član povjerenstva)
• Committee member: Iva Movre Šapić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2015-11-27, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Chemical Engineering in Material Development

Abstract

U ovome radu su pripremljene i okarakterizirane elektrode grafena i kompozita grafen/manganov oksid. Grafen je pripremljen redukcijom grafen oksida s NaBH4. Dobiveni produkt je nanesen na površinu staklastog ugljika sam (GBV1, GBV2) ili u kombinaciji s vezivom (GV2, GV3). Količina grafena koja je nanesena je varirala s ciljem da se utvrdi ovisnost svojstva elektrode o količini nanesenog materijala. Ispitivanje grafenom modificirane elektrode je provedeno metodom cikličke votametrije u 0,5 mol dm^-3 otopini Na2SO4, te pretražnim elektronskim mikroskopom (SEM). Prilikom ispitivanja elektrode metodom cikličke voltametrije u svim slučajevima dobivena je gotovo konstantna struja po potencijalu što ukazuje na dobra kapacitivna svojstva. Veći specifični kapaciteti su dobiveni u slučajevima kada nije korišteno vezivo. Na grafen modificiranim elektrodama provedena je kronoamperometrijska depozicija MnO2 Dobiveni kompoziti su ispitani metodom cikličke voltametrije u 0,5 mol dm^-3 otopini Na2SO4 te u otopini iz koje je provedena sinteza odnosno u prisutnosti Mn2+ iona. U svim slučajevima su dobivena dobra pseudokapacitivna svojstva te su dobiveni nešto veći kapaciteti u otopini MnSO4 u odnosu na Na2SO4 otopinu. Različito ponašanje je posljedica razlike u veličini kationa koji se interkalira tijekom redoks reakcije. Veće vrijednosti specifičnih kapaciteta su također dobivene za tanje slojeve manganovog oksida te kod grafen modificiranih elektroda kod kojih je korišteno vezivo. Dobivene vrijednosti specifičnih kapaciteta su se kretale u rasponu od 324-51 Fg^-1.

Abstract (english)

In this work samples of graphene and graphene/manganese oxide were prepared and characterised. Graphene was prepared by graphene oxide reduction using NaBH4. The obtained product was applied to the glassy carbon surface with or without the binder. The amount of graphene is varied in order to find out the dependence of properties on the amount of active material. The electrodes prepared in this manner were tested by cyclic voltammetry method in 0.5 mol dm^-3 NaSO4 solution and by scanning electronic microscopy (SEM). In all cases good capacitive properties were obtained. Higher capacitance was obtained when no binder was used. The graphene modified electrode was used as a support for chronoamperometry deposition of MnO2. The obtained electrodes were examined by cyclic voltammetry method in 0.5 mol dm^-3 NaSO4 and 0.25 mol dm^-3 MnSO4 solution whereat good pseudocapacitive properties were obtained in both systems. Due to the smaller Mn2+ size a higher amount of cations is intercalated within the layer and higher pseudocapacitive values are obtained in MnSO4 solution. Additionally, higher pseudocapacitive values of MnO2 are obtained for thinner layers and when graphene with binder was used. The obtained specific capacitance values ranges between 324 and 51 F g^-1.

• Keywords: grafen; manganov oksid; superkondenzatori
• Keywords (english): graphene; manganese oxide; supercapacitors
• Language: croatian
• URN:NBN: urn:nbn:hr:149:016973
• 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: magistar/magistra primijenjene kemije (magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-03-20 13:47:49