CINDECA 05422
CENTRO DE INVESTIGACION Y DESARROLLO EN CIENCIAS APLICADAS "DR. JORGE J. RONCO"
Unidad Ejecutora - UE
artículos
Título:
?SYNTHESIS AND CHARACTERIZATION OF MODIFIED FERRITES WITH Co AND Mg FROM LAYERED DOUBLE HYDROXIDES: DETERMINATION OF BAND GAP ENERGY AND MAGNETIC PROPERTIES?.
Autor/es:
U. AGÚ; MARCOSI.OLIVA; SERGIO G. MARCHETTI; A. HEREDIA; S. CASUSCELLI; M. CRIVELLO
Revista:
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2014 vol. 369 p. 249 - 259
ISSN:
0304-8853
Resumen:
A mixtureofnanocrystalsofcobaltferriteandmagnesiumferritewasobtainedfromLayeredDoubleHydroxides(LDH)throughaco-precitationmethodwithatheoreticalmolarratioM2þ:Fe3þ¼3:1,whereM2þrepresentsMg2þ and/or Co2þ. ThemolarratiosbetweenCo2þ:Fe3þ were0.0(0Co),0.2(5Co),and0.4 (10Co).InordertoassesstheeffectonthepropertiesoftheLDHandtheiroxides,themolarpercentageswere0,5and10%.Twodifferentsynthesismethodswereevaluated;(i)ageingatroomtemperature(rt),and(ii)hydrothermalageingat200 1C inautoclave(ht),bothmethodsneeded15hofageing. Then,theseLDHwerecalcinedinairatmosphereat550 1C for10h.ThecalcinedmaterialswerecharacterizedbyX-raydiffraction(XRD),thermogravymetricanalysis(TGA),temperature-programmedreduction (TPR),infraredspectroscopywithFouriertransform(FTIR),DiffuseReflectance UV?visiblespectroscopy(UV?vis-DRS), Mössbauerspectroscopyandinductivelycoupledplasmaopticalemissionspectroscopy(ICP?OES). Themagneticresponsewasanalyzedusingavibratingsamplemagnetometer(VSM). ThebandgapenergyoftheironoxideswasdeterminedthroughtheUV?vis-DRS analysis.Through thesestudiesitwaspossibletoidentifythepresenceofamixtureofcobaltferriteandmagnesium ferrite.Samplesdidnotshowhematiteandcobaltoxides,butthepresenceofMgOinthepericlase phasewasdetermined.Thismagnesiumoxidepromotedagooddispersionoftheferrites.Moreover,whenasingleferritephaseofCoorMgwasformed,adiminutionofthecrystalsizewithconsequentenlargedvaluesofbandgapenergywasobserved.Thus,materialssynthesizedbyroomtemperatureageingpromotedthesuperparamagneticbehaviourofsamples,attributedtothecontentofthe cobaltferritestructureinnanocrystals.Inregardtotheestimatedbandgapenergy,allsamplesexhibitedlowlevels.Theseresultsindicatethatthesesolidswouldbesuitableforphotocatalystsuseinall visiblelightrange,andthattheycouldbeeasilyremovedfromthereactionmediumbyasimplemagnetic separationprocedure.
