Kemijska i elektrokemijska modifikacija grafen oksida

undergraduate thesis

• Title (english): Chemical and electrochemical modification of graphene oxide
• Author: Ivan Spajić
• Mentor: Zoran Mandić (mentor)
• Committee member: Zoran Mandić (predsjednik povjerenstva)
• Committee member: Mirela Leskovac (član povjerenstva)
• Committee member: Marijana Kraljić Roković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2015-07-10, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Chemical Engineering in Material Development

Abstract

U ovom radu su pripravljene i ispitane četiri različite elektrode od grafen oksida
(GO). Sinteza GO-a provedena je iz grafita prema Staudenmaier metodi. Priređeni GO
nanešen je na zlatom prevučenu kvarcnu elektrodu te je provedena funkcionalizacija
GO-a s anilinom s ciljem priprave i ispitivanja elektroda za potencijalnu primjenu u
superkondenzatorima. Pripremljene elektrode se razlikuju prema načinu
funkcionalizacije (uz korištenje NHS-EDC reagensa i bez reagensa), te prema ispiranju
funkcionaliziranih elektroda (s vodom i s metanolom). Ispitivanja funkcionaliziranih GO
elektroda su provedena metodom cikličke voltametrije i pomoću elektrokemijske kvarckristalne
nanovage (EQCN).
Funkcionalizirani GO je pokazao vrlo dobra elektrokemijska svojstva, dobru
vodljivost električne struje, te obećavajuće rezultate za primjenu ovakvih elektroda u
superkondenzatorima. Prilikom funkcionalizacije GO-a došlo je do fizikalne adsorpcije
anilina na GO-u, a tijekom voltametrijskih i EQCN ispitivanja elektroda dolazi do
oksidacije anilina na potencijalima iznad 700 mV prema Hg/Hg2Cl2 referentnoj
elektrodi. Kao rezultat oksidacije anilina nastaje produkt čiji strujni vrhovi oksidacije i
redukcije kontinuirano rastu s opetovanim ciklusima oksidacije anilina. Dobiveni strujni
vrhovi se nalaze na potencijalima na kojima može doći do oksidacije ili dimera anilina
(p-aminodifenilamina) ili produkta koji u sebi sadrži fenazenske prstenove. Budući da je
elektroda poprimila zelenu boju karakterističnu za polianilin najvjerojatnije je da su se
na elektrodi formirali visokomolekularni lanci koji sadrže veliki udio fenazenskih
prstenova.

Abstract (english)

In this work four different electrodes based on graphene oxide (GO) were
prepared. Graphite was used as the starting material for the GO synthesis according to
the Staudenmaier method. The prepared GO was deposited on gold covered quartz
crystal electrode and its functionalization by aniline was carried out in order to prepare
the electrodes and to test them for the potential use in supercapacitor applications. Four
synthesised electrodes differ in the functionalization method (with or without NHS/EDC
reagent) and washing approach (water or methanol). The electrodes were tested by
cyclic voltammetry method and using quartz crystal nanobalance.
Functionalized GO showed excellent electrochemical properties, good electrical
conductivity and promising results for its application in supercapacitors. Aniline was
physisorbed on GO during functionalization and applying the potentials above 700 mV
vs. Hg/Hg2Cl2 reference electrode, the oxidation of aniline ensued. As the result of
aniline oxidation new species were formed which gave rise to the new redox peaks at
lower on the voltammograms. The oxidation/reduction currents for the new redox
peaks continuously increased with each subsequent cycle of aniline oxidation. The
potentials of the new current peaks correspond either to the oxidation/reduction of
aniline dimer, p-aminodiphenylamine, or to the product which contains phenazine rings.
Since the electrode exhibited green colour characteristic of polyaniline structure, it
seems obvious to conclude that macromolecular polyaniline chains with high content of
phenazine rings were formed on the electrode.

• Keywords: grafen oksid (GO); anilin; funkcionalizacija; superkondenzator; fenazen
• Keywords (english): graphene oxide (GO); aniline; functionalization; supercapacitor; phenazine
• Language: croatian
• URN:NBN: urn:nbn:hr:149:424291
• Study programme: Title: Materials Science and 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: 2016-09-12 13:01:39