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Unique Ordered TiO2 Superstructures

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DOI:10.1002/chem.201200515

UniqueOrderedTiO2SuperstructureswithTunableMorphologyand

CrystallinePhaseforImprovedLithiumStorageProperties

ZhenshengHong,YuxiaXu,YubinLiu,andMingdengWei*[a]

Introduction

Thesynthesisofsuperstructuresthroughthecontrolledself-

assemblyofnanoparticlesisaverypromisingandpotential-

lyhigh-impacttechnique;thismethodcanleadtounique

chemicalandphysicalproperties,andnewcollectivefunc-

tions.[1–3]Mesocrystalshavethereforereceivedincreasingat-

tentionfromchemistsandmaterialsscientistssincethey

werefirstreportedbyCçlfenetal.[4]Mesocrystalsareanew

classofsuperstructuredmaterials,andarecomposedofcrys-

tallinenanoparticleswithamutualorientationbetweenthe

nanocrystalbuildingunits.Amesocrystalissimilartoazeo-

liteinthatbothofthemareporoussinglecrystals;however,

mesocrystalspossessignificantversatilityintheirchemical

compositions,andhavethepotentialtoallowtheintroduc-

tionofavarietyoffunctionalproperties.Also,thedefinity

oftheirporesisdifferent.[5]Mesocrystalsalsopossessthe

advantagesinheritedfromsinglecrystalsandtheirlargespe-

cificsurfacearea,andthusareconsideredaspromisingsub-

stitutesforsingle-crystallineorpolycrystallinematerials.[4,6,7]

Forinstance,specificenergystoragematerialsfabricatedby

hierarchicalandporousmesocrystalscanbeconsideredas

idealforlithiumionbatteries(LIBs)withhighrateperfor-

mance.[6,8,9]Specifically,theinternalframeworkofthese

mesocrystallinematerialsprovideseasycontactfortheelec-

trolyte,andallowstheefficienttransportandinsertionofLi

ions.TiO2hasbeenconsideredasapotentialanodematerial

forLIBs,duetoitsintrinsicadvantagesinsafety,lowcost,

andgoodcyclicstability.[10–12]Ingeneral,theperformanceof

TiO2dependslargelyonitscrystallinephase,size,surface

stateandmicrostructures.[13–14]Accordingly,varioustech-

niquesandmaterialshavebeenadoptedtosynthesizeTiO2nanostructureswithvariousmorphologies,includingnano-

particles,nanowires,nanotubes,nanosheetsandthree-di-

mensionalarchitectures.[15–20]Inparticular,3Dnanostruc-

turesorsuperstructuresofTiO2orothermetaloxidespro-

videtheenvironmentthatisbestoptimizedtofacilitatethe

Li+charge/dischargeprocess;thisresultsinsuperiorelectro-

chemicalactivitycomparedwithnanoparticles.[9,20–22]How-

ever,thesynthesisofTiO2nanostructureswithcomplex

morphologiesremainsdifficult,duetotherapidhydrolysis

ofTi-containingprecursorsinaqueoussolutions.Toreduce

thehydrolysisrateoftheTi-containingprecursors,organic

additivesaretypicallyusedinthereactionsystem;however,

thesearestilltooexpensiveandlimitedforlarge-scaleap-

plications.ThesynthesisofTiO2nanostructureswithtunable

morphologyandphase,therefore,remainsamajorchal-

lenge,particularlyinfabricatingorderedsuperstructures,or

so-calledmesocrystals.

Inourpreviouswork,wedescribedafavorableroutefor

theadditive-freesynthesisofTiO2mesocrystalsusinghydro-

gentitanateasaprecursor.[23]Inthiscase,thephasetransi-

tionfromtitanatetotitaniawasachievedslowly;thistech-

niquemightthereforeprovideafavorabletitaniumsource

forthecontrollablesynthesisofTiO2superstructures.

Herein,wedescribetheadditive-freesynthesisofuniqueor-

deredTiO2superstructureswithtunablemorphologyand

phasethroughtheuseofdifferentcounterions.Inthepres-

entstudy,thedumbbell-shapedrutileTiO2andnanorod-like

rutilemesocyrstalsconstructedfromultrathinnanowires,Abstract:UniqueorderedTiO2super-

structureswithtunablemorphology

andcrystallinephaseweresuccessfully

preparedbytheuseofdifferentcoun-

terions.Dumbbell-shapedrutileTiO2andnanorod-likerutilemesocrystals

constructedfromultrathinnanowires,

andquasi-octahedralanataseTiO2mesocrystalsbuiltfromtinynanoparti-

clesubunitswereachieved.Interesting-

ly,theobtainedanatasemesocrystalshaveafinemicroporousstructureand

alargesurfacearea.Theinfluenceof

thecounterionsinthereactionsystem

isdiscussedandpossiblemechanisms

responsiblefortheformationofthe

uniqueorderedTiO2superstructureswithdifferentmorphologiesandcrys-

tallinephasesarealsoproposedbased

onaseriesofexperimentalresults.The

obtainedTiO2superstructureswere

usedasanodematerialsinlithiumion

batteries,andexhibitedhighercapacity

andimprovedrateperformance;thisis

attributedtotheintrinsiccharacteris-

ticsofthemesoscopicTiO2superstruc-

tures,whichhaveasingle-crystal-like

andporous

nature.Keywords:lithiumionintercala-

tion·mesocrystals·nanostructures·

orderedsuperstructures·titanium

[a]Z.Hong,Y.Xu,Y.Liu,Prof.M.Wei

InstituteofAdvancedEnergyMaterials,FuzhouUniversity

Fuzhou,Fujian350002(China)

E-mail:wei-mingdeng@fzu.edu.cn

SupportinginformationforthisarticleisavailableontheWWW

underhttp://dx.doi.org/10.1002/chem.201200515.

Chem.Eur.J.2012,18,10753–10760󰀂2012Wiley-VCHVerlagGmbH&Co.KGaA,Weinheim

10753FULLPAPER

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Cu-puzzle

Cu-puzzle

ISSN 1359-7345Chemical Communications

/chemcommVolume 46 | Number 12 | 28 March 2010 | Pages 1973–2152

COMMUNICATIONQingyi Lu and Feng Gao et al.Glucose-assisted synthesis of copper micropuzzles and their application as nonenzymatic glucose sensorsGlucose-assistedsynthesisofcoppermicropuzzlesandtheirapplication

asnonenzymaticglucosesensorsw

HuanPang,aQingyiLu,*aJianjunWang,bYechengLiaandFengGao*b

Received(inCambridge,UK)22ndSeptember2009,Accepted5thJanuary2010

FirstpublishedasanAdvanceArticleontheweb22ndJanuary2010

DOI:10.1039/b919764h

Glucosewasusedtosynthesizehigh-qualityCumicroplates

whichunderwentinsitularge-scaleassemblyintopuzzle-like

patterns.Themicropuzzleswereappliedtononenzymatic

glucosesensors.Theas-preparedCumicropuzzle-modified

electrodeshowsgoodlineardependenceandhighsensitivity

andselectivitytoglucoseconcentrationchange.

Preparation and in-Situ Spectroscopic Characterization

Preparation and in-Situ Spectroscopic Characterization

Preparationandin-SituSpectroscopicCharacterizationofMolecularlyDispersedTitanium

OxideonSilica

XingtaoGao,†SimonR.Bare,‡J.L.G.Fierro,§MiguelA.Banares,§andIsraelE.Wachs*,†

DepartmentofChemistryandChemicalEngineering,ZettlemoyerCenterforSurfaceStudies,LehighUniVersity,7AsaDriVe,Bethlehem,PennsylVania18015;UOPResearch,DesPlaines,Illinois60017;andInstitutedeCatalisisyPetroleoquimica,C.S.I.C.,CampusUniVeritarioCantoblanco,E-28049-Madrid,Spain

ReceiVed:March10,1998

ThemolecularlydispersedTiO2/SiO2supportedoxideswerepreparedbytheincipientwetnessimpregnation

of2-propanolsolutionsoftitaniumisopropoxide.Experimentalmonolayerdispersionofsurfacetitanium

oxidespeciesonSiO2wasreachedat∼4Tiatoms/nm2withatwo-stepimpregnationprocedure.Thesurface

structuresofthemolecularlydispersedTiO2/SiO2undervariousenvironmentswereextensivelyinvestigated

铋层状氧化物单晶薄膜多铁性研究进展

铋层状氧化物单晶薄膜多铁性研究进展

铋层状氧化物单晶薄膜多铁性研究进展

翟晓芳;云宇;孟德超;崔璋璋;黄浩亮;王建林;陆亚林

【摘 要】室温单相多铁材料非常稀缺,磁性元素掺杂的铋层状钙钛矿结构Aurivillius相氧化物是一类重要的单相室温多铁材料,但由于缺少单晶类样品,这一类多铁材料研究主要是围绕多晶类块体或者多晶薄膜展开,它们的磁、电等性能研究大都采用宏观探测方式,因此这类多铁材料的多铁性机理研究进行得非常困难.近年来在高质量单晶薄膜的基础上,研究了多种磁性元素掺杂和不同周期结构的铋层状氧化物多铁单晶薄膜.这些单晶薄膜在室温下大都具有层状面面内方向的铁电极化,以及比较小的室温磁化强度,低温区存在第二个磁性相变.通过X射线共振非弹性散射实验发现元素掺杂会改变金属和氧原子之间的氧八面体晶体场的劈裂,能够增强铁磁性.另一方面,通过极化中子反射实验发现薄膜主体的磁化强度远小于通常探测的宏观磁化强度,说明单晶薄膜中磁的来源及其磁电耦合机理和多晶块体很可能是不同的.铋层状单晶薄膜的多铁性对未来继续改善这类材料的多铁性能有很好的指导作用.

【期刊名称】《物理学报》

【年(卷),期】2018(067)015

【总页数】17页(P322-338)

【关键词】铋层状氧化物;多铁;单晶薄膜;磁性

【作 者】翟晓芳;云宇;孟德超;崔璋璋;黄浩亮;王建林;陆亚林

【作者单位】中国科学技术大学, 合肥微尺度物质科学国家研究中心, 合肥 230026;中国科学技术大学, 合肥微尺度物质科学国家研究中心, 合肥 230026;中国科学技术大学, 合肥微尺度物质科学国家研究中心, 合肥 230026;中国科学技术大学, 合肥微尺度物质科学国家研究中心, 合肥 230026;中国科学技术大学, 国家同步辐射实验室, 合肥 230026;中国科学技术大学, 国家同步辐射实验室, 合肥 230026;中国科学技术大学, 合肥微尺度物质科学国家研究中心, 合肥 230026;中国科学技术大学,

金属载体强相互作用

金属载体强相互作用

肉桂醇是香料、药物及其他精细化工产品生产过程中的重要原料 和反应中间体，目前工业上生产肉桂醇的方法多局限在均相计量还原 法上，但其反应条件苛刻、还原剂用量大、反应后产物分离繁琐、产 生大量废弃物，不符合可持续经济发展的要求，而采用多相催化加氢 的方法具有反应条件温和、还原剂(氢气)绿色无污染、催化剂易于 分离、可循环使用等特点，因此研制经济高效的肉桂醛选择加氢催化 剂具有重要的学术意义和经济价值。【2】599

肉桂醇可作为医药原料，常用于心脑血管药物的合成，如脑益嗦

等，对病毒引起的肺瘤能有效抑制；临床用于血癌、子宫癌、卵巢肿

瘤、食管癌等多种肿瘤。

【8】Chambers A, Jaekson S D, Stirling D,Webb G Selective

Hydroge natio n of Cinn amaldehyde over Supported Copper

Catalysts[J].

J Catal,1997,168(2):301 — 314.

载体

载体本身的比表面积、浸润性及载体与纳米金粒子间的相互作用

1. Fe离子沉积增加了催化剂有效比表面积，减小了 Au颗粒尺寸.

[5]K.M. Parida et al. Low temperature CO oxidation over gold supported

mesoporous Fe-TiQ. J. Mol. Catal. A319 (2010) 92- 972. 具有大比表面积的载体是金颗粒高度分散的前提， 而载体的浸润性

决定了金催化剂在焙烧过程中是否会团聚成大的金颗粒 ，若团聚其

催化活性降低。[6]898

3. 载体与纳米金颗粒之间的相互作用强度也是影响催化活性的关键

因素。(几何效应)当金颗粒以半球状附着在载体表面时与载体表面 的相互作用较强，由于半球状附着在载体表面上的金的自由能要比球 状附着在载体表面上的自由能大，所以半球状的金颗粒更容易吸附 反应介质以降低其自由能，因此，其催化活性一般较高；而以球状附 着在载体表面时金颗粒难吸附反应介质，使得其催化活性较低。因此, 金与载体间的相互作用力越强，金粒子在载体表面的形状越扁平，因此 催化活性越高。另外，这种相互作用也能使金的电子结构发生变化 , 通常当金负载在可还原性的载体上时 ，由于载体的氧缺陷位与金之