Title Fotokatalitična svojstva cinkovog oksida pripremljenog termičkom razgradnjom celuloznog predloška Title (english) Photocatalytic properties of zinc oxide prepared by thermal degradation of the celulose template Author Rafaela Radičić Mentor Gabriela Ambrožić (mentor)Committee member Robert Peter (predsjednik povjerenstva)Committee member Gabriela Ambrožić (član povjerenstva)Committee member Iva Šarić (član povjerenstva)Granter University of Rijeka Defense date and country 2020-09-24, Croatia Scientific / art field, NATURAL SCIENCES Abstract Cilj ovog rada je priprema, karakterizacija i istraživanje fotokatalitičkih svojstava i) hi- bridnih materijala na osnovi celuloze i cink oksida (ZnO), i ii) ZnO struktura koje smo dobili žrtvovanjem polimernog predloška termičkom degradacijom organske (polimerne) komponente prethodno priremljenog hibrida. Hibridne materijale smo pripremili na- rastanjem ZnO na dva različita celulozna predloška, Sodra Green T i UPM Conifer, putem termičke depozicije atomskih slojeva (t-ALD) i plazmom
... More potpomognute ALD (PEALD) metode. Pri tome smo primjenili standardne procesne uvjete za rast 50 nm filma ZnO na silicijevom supstratu. Dobivene hibride ZnO i celuloze smo kalcini- rali jedan sat u programibilnoj peći Carbolite Gero do 700 ◦C s namjerom dobivanja čistog ZnO. Uzorke smo karakterizirali pomoću pretražnog elektronskog mikroskopa s emisijom polja (FE-SEM), spektroskopije fotoelektrona rendgenskim zrakama (XPS) i masene spektrometrije sekundardnih iona (SIMS). FE-SEM slike su pokazale da kalci- nirani uzorci imaju veću aktivnu površinu kao posljedica nastanka poroznih tubularnih struktura sastavljenih od sinteriranih nanočestica ZnO. Iz XPS spektara je vidljiva prisutnost veće količine reaktivnih OH grupa kod ZnO deponiranog na celulozi Sodra Green T što ukazuje na bolje fotokatalitičke aktivnosti. Za razliku od silicijevih sups- trata, gdje pod primjenjenim procesnim uvjetima t-ALD i PEALD metoda narastaju 50 nm filmovi ZnO, SIMS spektri su potvrdili da je brzina rasta ZnO na celuloznim pred- lošcima pod analognim uvjetima veća kod filmova dobivenih s termičkim ALD-om. U ispitivanju fotokatalitičke aktivnosti smo koristili metil oranž (MO) kao modelni organ- ski polutant te smo pomoću UV/Vis spektrofotometra pratili promjene u apsorbanciji otopine MO. Nakon kalcinacije hibridnih materijala, dobiveni uzorci ZnO su pokazali jaku fotokatalitičku aktivnost. Unutar 80 min dolazi do potpune mineralizacije i deko- lorizacije MO, dok prije kalcinacije uzoraka unutar 240 min nije došlo do dekolorizacije niti do mineralizacije MO. ZnO deponiran na celulozi Sodra Green T putem t-ALD i PEALD metoda ima gotovo istu fotokatalitičku aktivnost neovisno o metodi depozi- cije. ZnO deponiran na celulozi UPM Conifer putem t-ALD metode se pokazao boljim fotokatalizatorom od onog pripremljenog putem PEALD metode. Less Abstract (english) The aim of this work is to prepare, characterize and investigate the photocatalytic properties of hybrid materials based on i) cellulose and zinc oxide (ZnO), and ii) ZnO structures obtained by a polymer templated thermal decomposition of the previously prepared ZnO/cellulose hybrids. The hybrid materials were prepared by growing thin films ZnO on two different cellulose substrates, Sodra Green T and UPM Conifer, using thermal atomic layer deposition (t-ALD) and plasma-assisted
... More atomic layer deposition (PEALD) methods. In doing so, we applied standard process conditions for the growth of a 50 nm ZnO film on a silicon substrate. The hybrids were calcined for one hour in a programmable Carbolite Gero furnace at 700 ◦C with the intention of obtaining pure ZnO. The samples were characterized using a field emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). FE-SEM images showed that calcined samples have a larger active surface area as a result of the formation of solid porous tubular structures. The XPS spectrum shows the presence of a larger amount of reactive surface OH groups in ZnO precipitated on Sodra Green T cellulose, indicating better photocatalytic activities. In contrast to silicon substrates, where 50 nm ZnO films grow under the applied t-ALD and PEALD processing conditions, SIMS spectra confirmed that the growth rate of ZnO on cellulose templates under analog conditions is higher in films obtained by t-ALD. In the study of photocatalytic activity of the samples, we used methyl orange (MO) as a model organic pollutant. Changes in the absorbance of the MO solution were monitored using a UV / Vis spectrophotometer. After calcination of the hybrid materials, the resulting ZnO showed strong photocatalytic activity; within 80 min there is a complete mineralization and decolorization of MO, while before calcination of samples within 240 min there was no discoloration or mineralization of MO. ZnO deposited by the t-ALD and PEALD methods on Sodra Green T show almost the same photocatalytic activity. ZnO deposited on UPM Conifer cellulose by the t-ALD method proved to be a better photocatalyst than that prepared by the PEALD method. Less Keywords
cinkov oksid
celuloza
termička depozicija atomskih slojeva
plaz- mom potpomognuta depozicija atomskih slojeva
fotokataliza
metil oranž
UV/Vis spektroskopija
pretražni elektronski mikroskop
spektroskopija fotoelektrona rendgen- skim zrakama
masena spektrometrija sekundardnih iona
Keywords (english)
zinc oxide
cellulose
thermal atomic layer deposition
plasma en- hanced atomic layer deposition
photocatalysis
methyl orange
UV/Vis spectroscopy
scanning electron microscope
X-ray photoelectron spectroscopy
secondary ion mass spectrometry
Language croatian URN:NBN urn:nbn:hr:194:584787 Study programme Title: physics Type of resource Text File origin Born digital Access conditions Access restricted to students and staff of home institution Terms of use Created on 2020-10-16 11:11:20
