[emuch.net][726773]A self-templated route to hollow silica microspheres

《[emuch.net][726773]A self-templated route to hollow silica microspheres》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、3168J.Phys.Chem.C2009,113,3168–3175ASelf-TemplatedRoutetoHollowSilicaMicrospheresTieruiZhang,†QiaoZhang,†JianpingGe,†JamesGoebl,†MinweiSun,‡YushanYan,‡Yi-shengLiu,§,

2、ChinglinChang,

3、JinghuaGuo,§andYadongYin†,*DepartmentofChemistryandDepartmentofChemicalandEnVironmentalEngineering,UniVer

4、sityofCalifornia,RiVerside,California92521,DepartmentofPhysics,TamkangUniVersity,Tamsui251,Taiwan,andAdVancedLightSource,LawrenceBerkeleyNationalLaboratory,Berkeley,California94720ReceiVed:NoVember25,2008;ReVisedManuscriptReceiVed:December29,2008Asimple,mild,andeffectiveself-templateda

5、pproachhasbeendevelopedtodirectlyconvertsolidSiO2microspheresintohollowstructures.ThereactioninvolvesinitialpartialdissolutionofsilicacoresinaNaBH4solutionandsubsequentshellformationduetotheredepositionofthesilicatespeciesbackontothecolloidsurfaces.TheincreasingconcentrationofNaBO2asth

6、eresultoftheslowdecompositionofNaBH4inwaterisfoundtoberesponsiblefortheregrowthofthesilicashell.Thismethodallowstheproductionofhollowsilicasphereswithsizesrangingfrom∼70nanometerstoseveralmicrometers,largelydeterminedbythesizeofthestartingsilicacolloids.Thesolid-to-hollowtransformation

7、mechanismisinvestigatedindetailbytransmissionelectronmicroscopy(TEM),scanningelectronmicroscopy(SEM),FourierTransformInfrared(FTIR)spectrometry,X-rayabsorptionspectroscopy(XAS),N2adsorption-desorption,andX-raydiffraction(XRD).Wealsostudythereactionconditionsthatallowcontroloverthewallt

8、hickness,surfacemorphology,andshellporosity.1.IntroductioninanaqueoussolutionofNaBH4,undergoaspontaneousmorphologychangefromsolidtohollowspheres.31TheManysyntheticprocedureshavebeendevelopedinrecentformationofhollowsilicaspheresisbasedonthespontaneousyearsforthepreparationofhollowmicro

9、-andnanostructures,dissolutionandregrowthofsilicaatthenanometerscale.Suchlargelybecauseoftheirwideapplicationsindrugdelivery,aprocessisdifferentfromthewell-demonstratedsacrificialphotoniccrystals,sensing,energy-storagemedia,andnano-1-8templatingproceduresinmanyregards:(a)Thismethodisv