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1、AFacileHydrothermalRoutetoSynthesize3DWhisk-broom-likeLanthanumOrthovanadateJianboTan,JianxinShi*,JilinZhang,MenglianGongSchoolofChemistryandChemicalEngineering,SunYat-SenUniversity,Guangzhou510275,People’sRepublicofChinaAbstract:Three-dimensional(3D)whisk-broom-likezircon-typelanth
2、anumorthovanadatewassynthesizedbyanethylenediaminetetraaceticacid(EDTA)-mediatedhydrothermalmethod.TheproductswerecharacterizedbyusingXRD,SEM,TEMandEDS.TheexperimentalresultsshowedthatthemorphologyandmicrostructureofLaVO4nanocrystalswereinfluencedbyEDTA/La3+ratio,reactiontime,initia
3、lpH,vanadatesource,andNa+cation.Apossiblegrowthmechanismof3Dwhisk-broom-likelanthanumorthovanadatewasalsoproposed.ThemagneticpropertiesmeasurementsshowedthatNeeltemperatureofthepreparedwhisk-broom-liket-LaVO4ishigherthanthatofLaVO4nanorods.Keywords:hydrothermalmethod;lanthanumorthov
4、anadate;three–dimensionalstructure;magneticproperties1.IntroductionLanthanideorthovanadateshaverecentlyattractedmuchattentionduetotheirunusualmagneticcharacteristicsandusefulluminescentproperties.1-8Andtheycanalsobeusedascatalystsfortheoxidativedehydrogenationofpropanetopropene.9Lan
5、thanideorthovanadatescrystallizeintwopolymorphsofmonoclinic(m-)monazite-typeandtetragonal(t-)zircon-type.Withincreasingionicradius,Ln3+ionsshowastrongtendencytowardmonazite-structuredorthovanadateduetoitshigheroxygencoordinationnumberof9ascomparedwith8ofthezirconone.Therefore,thethe
6、rmodynamicallystablestateismonazite-typeforlanthanumorthovanadate(LaVO4),whilezircon-typefortheotherorthovanadates.9Thezircon-typeorthovanadateshavemuchbettermagneticandluminescentpropertiesthanthemonazite-type.3-5,9Themonazite-typeLaVO4canbesynthesizedthroughthehydrothermalormechan
7、ochemicalreaction.3,9,10Becauseofitsmetastability,zircon-typeLaVO4canbeonlysynthesizedwiththehydrothermalmethod,suchasethylenediaminetetraaceticacid(EDTA)-mediated,1,2,9theselected-controlsynthesisbytuningthepHvaluesofthesolution,3,4andalsothemicroemulsion-mediated.11中山大学化学与化学工程学院第九
8、届创新化学实验与研究基金项目第一作者：
