TOF的计算方法_精品文档资料下载.pdf
- 文档编号:16120060
- 上传时间:2022-11-20
- 格式:PDF
- 页数:17
- 大小:6.01MB
TOF的计算方法_精品文档资料下载.pdf
《TOF的计算方法_精品文档资料下载.pdf》由会员分享,可在线阅读,更多相关《TOF的计算方法_精品文档资料下载.pdf(17页珍藏版)》请在冰豆网上搜索。
SupportinginformationforSynthesisofPtPdBimetalNanocrystalswithControllableShape,CompositionandTheirTunableCatalyticPropertiesXiaoqingHuang,YujingLi,YongjiaLi,HailongZhou,XiangfengDuan,andYuHuang*DepartmentofMaterialsScienceandEngineering,DepartmentofChemistryandBiochemistry,andCaliforniaNanoSystemsInstitute,Univer-sityofCalifornia,LosAngeles,California90095,UnitedStatesEmail:
@#@yhuangseas.ucla.eduExperimentalDetailsChemicals:
@#@Sodiumtetrachloropalladate(Na2PdCl4,99.9%),Potassiumtetrachloroplatinate(K2PtCl4,99.9%),Sodiumchloride(NaCl,ACSreagent,99.5%),Sodiumbromide(NaBr,ACSreagent,99.5%),Sodiumiodide(NaI,ACSreagent,99.5%),Poly(vinylpyrrolidone)(PVP,MW55000)andN,N-dimethylformamide(DMF)wereallpurchasedfromSigma-Aldrich.Allthechemicalswereusedasreceivedwithoutfurtherpurification.Thewater(18M/cm)usedinallexperimentswaspreparedbypassingthroughanultrapurepurificationsystem(AquaSolutions).SynthesisofCubicPtPdNanocrystals:
@#@InatypicalsynthesisofcubicPtPdnanocrystals,sodiumtetrachloropalladate(Na2PdCl4,20mM,ie.0.67mL,1.0mLor1.33mL),potassiumtetrachloroplatinate(K2PtCl4,20mM,ie.1.33mL,1.0mLor0.67mL),sodiumiodide(NaI,75.0mg)andpoly(vinylpyrrolidone)(PVP,160.0mg)weremixedtogetherwith10mLN,N-dimethylformamideina22.0-mLvial.Afterthevialhadbeencapped,themixturewasultrasonicatedforaround2minutes.Theresultinghomogeneousmixturewastransferredintoaconventionalovenandheatedat130Cfor5hoursbeforeitwascooledtoroomtemperature.Theresultingcolloidalproductswerecollectedbycentrifugationandwashedseveraltimeswithanethanol-acetonemixture.SynthesisofOctahedralPtPdNanocrystals:
@#@InatypicalsynthesisofoctahedralPtPdnanocrystals,sodiumtetrachloropalladate(Na2PdCl4,20mM,ie.0.67mL,1.0mLor1.33mL),potassiumtetrachloroplatinate(K2PtCl4,20mM,ie.1.33mL,1.0mLor0.67mL),sodiumchloride(NaCl,29.3mg)andpoly(vinylpyrrolidone)(PVP,160.0mg)weremixedtogetherwith10mLN,N-dimethylformamideina22.0-mLvial.Afterthevialhadbeencapped,themixturewasultrasonicatedforaround2minutes.Theresultinghomogeneousmixturewastransferredintoaconventionalovenandheatedat130Cfor5hoursbeforeitwascooledtoroomtemperature.Theresultingcolloidalproductswerecollectedbycentrifugationandwashedseveraltimeswithanethanol-acetonemixture.Characterization:
@#@TEMimageswerecarriedoutonaFEICM120transmissionelectronmicroscopeoperatedat120kV.HighresolutionTEMimagesandthehigh-angleannulardark-fieldscanningtransmissionelectronmicroscopy(HAADF-STEM)-energy-dispersiveX-rayspectroscopy(EDS)wasweretakenonaFEITITANtransmissionelectronmicroscopeoperatedat300kV.Thesampleswerepreparedbydroppingethanoldispersionofsamplesontocarbon-coatedcopperTEMgrids(TedPella,Redding,CA)usingpipettesanddriedunderambientcondition.X-raypowderdiffractionpatternswerecollectedonaPanalyticalXPertProX-rayPowderDiffractometerwithCu-Kradiation.Theconcentrationofcatalystswasdeterminedbytheinductivelycoupledplasmaatomicemissionspectroscopy(TJARADIALIRIS1000ICP-AES).GeneralProcedureforHydrogenationofNitrobenzene:
@#@Inatypicalcatalyticreaction,nitrobenzene(2.0mmol),PtPdcatalystssuspensioninethanol(0.1mM,1.0mL)andethanol(9.0mL)weremixedtogetherandplacedintoaglasspressurevessel.Inordertoremovetheairfromthereactionsystem,thevesselwaspurgedwithH2beforethecatalyticreaction.Then,thevesselwaspressurizedwith1bar.Duringthecatalyticexperiment,thepressureofH2wasmaintainedconstant.TheintermediatecatalyticproductsproducedatdifferentreactiontimewereanalyzedbyGC-MS.Turn-Over-Frequency(TOF)Calculations(a)Generalconcept1.TOFofthecatalyst=(moleofnitrobenzeneconversion)/(moleofsurfaceatomsofcatalystreactiontime)2.SincebothPdandPthaveaface-centered-cubicstructurewithasimilarlatticeconstant(latticeconstantofPdis0.389nm,latticeconstantofPtis0.392nm),wecollectivelyusedalatticeconstantof0.39nminthealloyedPtPdnanocrystalsforthesimplicityofcalculation.So,thevolumeofaunitcellinPtPdnanocrystalsis(0.39nm)3=0.059nm3.Eachunitcellcontains4Pt&@#@Pdatoms.3.Anoctahedronwithanedgelengthofahasasurfaceareaof322aandavolumeof323a.Ancubewithanedgelengthofbhasasurfaceareaof62bandavolumeof3b.4.PtPdoctahedronisenclosedby111facet.Eachtwo-dimensionalunitcellonthe111facetscontains0.5Pt&@#@Pdatoms.Theareaofthisunitcellis341268.2=0.031nm2.PtPdnanocubeisenclosedby100facet.Eachtwo-dimensionalunitcellonthe100facetscontains2Pt&@#@Pdatoms.Theareaofthisunitcellis(0.39nm)2=0.15nm2.(b)NumberofPt&@#@PdatomsineachPtPdnanocrystalsNumberofPt&@#@PdatomsineachoctahedralPtPdnanocrystals=(volumeofeachoctahedron/volumeofeachunitcell)at
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- TOF 计算方法 精品 文档