Hidrotermalna sinteza bakrom dopiranog CeO2

undergraduate thesis

• Title (english): Hydrothermal synthesis of copper-doped ceria
• Author: Marin Božičević
• Mentor: Stanislav Kurajica (mentor)
• Committee member: Stanislav Kurajica (predsjednik povjerenstva)
• Committee member: Juraj Šipušić (član povjerenstva)
• Committee member: Jelena Macan (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2018-09-21, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Basic Technical Sciences; Materials

Abstract

Cerijev (IV) oksid (CeO2) najveću primjenu ima u katalitičkim reakcijama kao katalizator i kao nosač katalizatora u mnogim industrijskim procesima, a također i za smanjenje emisije štetnih plinova tako što katalizira reakcije oksidacije metana i ugljikovog monoksida. Dopiranje bakrom znatno poboljšava toplinsku stabilnost CeO2, što proširuje mogućnosti njegove primjene bez straha da će doći do prekomjernog sinteriranja. Hidrotermalnom sintezom pri 120 °C u vremenu od 16 h, uz korištenje 8 mol/L NaOH kao otapala dobiven je čisti CeO2, kao i bakrom dopirani CeO2 s molarnim udjelima bakra 5, 10, 15, 20, 25 te 30 %. Provedbom rendgenske difrakcijske analize (XRD) te infracrvene spektroskopije s Fourierovom transformacijom (FTIR) praćena je struktura produkata, veličina kristalita, parametar jedinične ćelije te način ugradnje bakra u strukturu CeO2. Iz podataka dobivenih eksperimentalnom analizom vidljivo je da se bakar ugrađuje u kristalnu rešetku CeO2 te zamjenjuje ione Ce4+ u unutrašnjosti rešetke, što rezultira smanjenjem veličine kristalita s povećanjem udjela bakra i to od 4,15 nm za čisti CeO2 do čak 3,1 nm za uzorak s 20 mol. % bakra. Iz difraktograma i FTIR spektara je vidljivo da s povećanjem udjela bakra ne dolazi do nastajanja nove faze koja bi ukazivala na formiranje CuO.

Abstract (english)

Ceria is mostly used in catalytic reactions both as catalyst and catalyst support in many industrial processes, and also to lower the emission of harmful gasses by catalyzing oxidation reactions of methane and CO. Adding copper as a doping material enhances the thermal stability, which leads to wider synthesis and processing options without fear of excessive sintering. Products of pure ceria and copper-doped ceria in 5, 10, 15, 20, 25 and 30 mol. % of copper were prepared by hydrothermal synthesis at 120 °C for 16 h, using 8 mol/L NaOH as solvent. Using X-ray diffraction (XRD) and Fourier transformation infrared spectroscopy (FTIR), the structure of products, crystallite size, unit cell constant and the way of embedding of copper into the CeO2 structure has been investigated. From the data obtained by experimental analyses it was clear that copper, as doping material, enters the ceria crystal structure and replaces Ce4+ ions, which results in smaller crystallite sizes by increasing molar fraction of copper, from 4,15 nm for pure ceria to 3,1 nm for sample with 20 mol. % of copper. From XRD patterns and FTIR spectra it is clear that no matter what molar fraction of copper was introduced into ceria, the CuO was not formed as a side product.

• Keywords: cerijev (IV) oksid; dopiranje; hidrotermalna sinteza
• Keywords (english): ceria; doping; hydrothermal synthesis
• Language: croatian
• URN:NBN: urn:nbn:hr:149:726788
• 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: 2022-07-08 12:12:51