材料专业文献翻译范本模板.docx

材料专业文献翻译范本模板.docx

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材料专业文献翻译范本模板

SynthesisandGasSensitivityofIn2O3/CdOComposite

Abstract:

Indiumoxide（In2O3）wassynthesizedusingahydrothermalprocess.ThecrystallographyandmicrostructureofthesynthesizedsampleswerecharacterizedbyX—raydiffraction（XRD）,scanningelectronmicroscopy（SEM）,energydispersiveX-rayspectroscopy（EDX）,andtransmissionelectronmicroscopy（TEM）。

TheIn2O3hadaflower—likehierarchicalnanostructureandwascomposedoftinynear—sphericalcrystalswithadiameterofapproximately20nm。

WhenIn2O3wasmixedwithCdOina1:

1molarratio,itwasfoundthattheresultingIn2O3/CdOcompositeshowedaninterestinggrape-likeporousmicrostructurefollowingcalcinationsatelevatedtemperatures.AgassensorusingthisIn2O3/CdOcompositeasthesensingmaterialshowedhighersensitivitytodifferentconcentrationofformaldehydethanthegassensorbasedonpureflower-likeIn2O3nanomaterials.TheIn2O3/CdO-basedsensorsshowedahighsensitivitytoaconcentrationof0.05×10—6formaldehydeattheoptimizedoperatingtemperatureof410°Candagoodlevelofselectivityoverotherpossibleinterferencegasessuchasethanol，toluene，acetone,methanol，andammonia.ThegassensingmechanismofIn2O3/CdOsensorhasbeendiscussedindetail。

1Introduction

Formaldehyde（HCHO）isacolorlessandstrong-smellinggascomingfrombuildingmaterials，interiordecorationmaterials,woodfurniture,carpetandsoon.

HCHOisoneofthemostdangerousindoorpollutantsamongvolatileorganiccompounds（VOCs）,andisfoundtobeassociatedwithasthma,nasopharyngeal

cancer，andmultiplesubjectivehealthcomplaints。

Inparticular,HCHOisconsideredasamajorcauseofsickbuildingsyndrome（SBS）。

WorldHealthOrganization（WHO）establishedastandardof0。

08×10-6（volumefraction）averagedover30minforlong—termexposureinformaldehydevapor.ManymethodstodetectVOCshavebeeninvestigated。

Amongthem,semiconductorgassensorsarewidelyusedsincetheyarecheapandeasytobeavailable。

Thesensingmaterials,includingSnO2，10-12ZnO,13NiO,14andIn2O3,15，16havebeenexploredforformaldehydedetection。

Inrecentyears,nanostructuresemiconductormaterialshavebeenextensivelystudiedduetotheirexceptionalpropertiesandpotentialapplicationsinvariousfields。

Amongthem,indiumoxide（energygap3。

67eV,Bohrradius2.14nm）materialhasbeenwidelystudiedbecauseofitsuniqueoptoelectronicproperties,suchashighelectricalconductivityandhighUVtransparency。

Ithasbeenwidelyusedintheoptoelectronicdevicessuchassolarcells,windowheaters,andliquidcrystaldisplays。

Ithasbeenalsoexploredforsensingmaterialsfordetecting

O3，HCHO,trimethylamine（TMA）,NO2CO,andNH3。

Variousvapor-phaseorphysicaltemplatemethodsweredevelopedtoprepareIn2O3nanocrystals。

Forexample，In2O3nanowiresweresynthesizedbyusingthevapor-liquid—solidtechnique。

TheIn2O3nanowirearraysornanorodswereinducedbytemplate—assistedgrowth，andtheIn2O3nanobeltswereobtainedthroughthermalevaporation。

Besidesthesephysicalmethods,therearealsowet-chemistrymethodstopreparespecificIn2O3nanostructures。

Forinstance,In2O3withstructuresofnanorodbundles，spherelikeagglomerates，lotus-root—like，andnanotubesweresuccessfullysynthesizedbyhydrothermalroute。

Quasi-monodisperseIn2O3nanocrystalswereobtainedthroughanorganicsolutionsyntheticroute.

Inthiswork,theflower-likehierachicalnanostructureIn2O3composedofthetinysphericalnanocrystallineswasfabricatedbyusingthehydrothermalmethod。

Then，theas-synthesizedIn2O3powdersweremixedwithCdOinamolarratioof1:

1toformagassensingmaterial.TheformaldehydesensingpropertiesoftheIn2O3/CdO—basedsensorswerecarriedout。

2Experimental

2.1Preparationandcharacterizationofmaterials

InCl3·4H2O（99.5％）wasobtainedfromSinopharmChemicalReagentCo。

Ltd。

，China。

Ethylenediaminetetraaceticacid（99.5％，EDTA,C10H16N2O8）andCS（NH2）2（99.0％）wereobtainedfromTianjinKermelChemicalReagentCo。

Ltd。

China.CdO（99。

5％）powderwasanalyticalgradewith30nmparticlesize,andpurchasedfromHaitaiNanometerMaterialsCo.,China.Allofthereagentsusedintheexperimentswereanalyticalgradeandutilizedwithoutfurtherpurification。

Flower—likeIn2O3wassynthesizedbyahydrothermalmethod。

Inatypicalprocedure，1mmolInCl3·4H2Oand2mmolCS（NH2）2weredissolvedin30mLEDTA。

Afewdropsofammoniaweredrippedintothesolution，andthesolutionwasundertheconditionsofultrasonicdispersingandconstantstirringalternatelyfor20min。

Then,themixturewastransferredintoa50mLTeflon-linedstainlesssteelautoclave。

Theautoclavewassealedandmaintainedinanelectricovenat180°Cfor18h.Afterthat,theautoclavewascooledtoroomtemperaturenaturally.Thepinkprecipitatewascollectedandwashedwithethanolanddeionizedwateralternatelyforseveraltimes。

Thenitwasdriedinelectricovenat80°Candtheprecursorwasgenerated。

FlowerlikeIn2O3wasobtainedbyroastingtheprecursorat600°Cinmufflefor1h.

X-raydiffraction（XRD）patternsofthepowderswereexaminedin2θregionof20°-80°withCuKα（0.154nm）radiationonRigaku,ModelD/MAX2400,Japan。

Scanningelectronmicroscopy（SEM）imageswereexaminedonaFEIQUANTA200F（UnitedStates）microscopeequippedwithenergydispersiveX-ray（EDX）spectroscopy。

Transmissionelectronmicroscopy（TEM）imagewascarriedouttoobtaindirectinformationaboutthesizeandstructurebyTecnaiG220S—Twintransmissionelectronmicroscope。

2.2Fabricationandmeasurementofgassensors

TheIn2O3andCdOpowdersweremixedinamolarradioof1:

1andgroundwithdeionizedwatertoformapaste.Thepastewaspaintedonacleanceramictube（Φ2mm×4mm）onwhichapairofAuelectrodeswerepreviouslyprinted，andthensinteredat600°Cfor2h.ANi-Crheatingwirewith30Ωasaheaterwasinsertedthroughthetubetoprovideheatingforgassensor.Theelectrodeandheaterwireswereweldedonabasetoformgassensor.Thefabricatedgassensorswereagedwithaheatingtemperatureof300°Cfor240hinair。

ThegassensingpropertiesofIn2O3/CdOcompositegassensorsweretestedinasealedchamber.Thetestingtemperatureandhumiditywere~20°Cand～20％RH（relativehumidity）,respectively。

Aheatingvoltagewhichwasprovidedbyad.c。

powersupply（GPS-3303C,GuweiElectronic，Taiwan）wassuppliedtothewireofsensorforprovidingaoperatingtemperature,andacircuitvoltagewassuppliedacrossthesensorandtheloadresistorconnectedtothesensorinseries。

Theoutputvoltageacrosstheloadresisterwasrecordedbyadataacquisitioncardwhichwasconnectedtoacomputertorecordthereal—timedata.Thewholesystemwascontrolledbyacomputerautomatically。

3Resultsanddiscussion

3。

1CharacterizationsofIn2O3andIn2O3/CdOcomposite

TheXRDpatternoftheIn2O3isshowninFig。

1。

AllpeakscanbeindexedtopurecubicphaseofIn2O3（JCPDSNo.65—3170）,indicatingthatapurephaseofIn2O3wasobtainedbycalciningtheprecursor。

ThecrystallinesizeoftheIn2O3wascalculatedbyusingDebyeScherrorformula，D=0.89λ/βcosθ，whereDistheaveragegrainsize,λistheX-raywavelength（0。

154nm），βisfull—widthathalf—maximum，andθisdiffractionangle.ThecalculatedaveragecrystallinesizeoftheIn2O3isabout22nm。

Fig。

2showstheSEMimagesoftheIn2O3material.Itcanbeseenthattheas-preparedIn2O3nanoparticleswerecongregatedtogetherandformedflower-likemicrostructurewithadiameterofseveraltotenmicrometers.Fig.2（b）showsthattherearemanywrinklesandholesonthe“flower”.

Fig。

3showstheTEMimageoftheas-synthesizedIn2O3。

TheIn2O3nanoparticlesareuniformandtheshapesofthecrystallitesaresphericalandellipse.ThegrainsizeoftheIn2O3isaround20nmconsistentwiththecalculatedresult。

FromFigs。

2and3，itcanbeseenthattheas—preparedflower—likeIn2O3particleswereformedwiththetinycrystallitesindicatingahierarchicalnanostructureinnature。

Theformationoftheflower—likehierarchicalstructureIn2O3byusingthehydrothermalmethodcouldbedescribedasfollows。

ThechemicalreactionoccurredintheInCl3mixtureduringthepreparationprocess:

In3++EDTA=In（EDTA）

（1）

Then，thefollowingreactionswerepresented：

NH3·H2O=NH4++OH-

（2）

CS（NH2）2+2OH—=S2-+CO2+2NH3（3）

2In（EDTA）+3S2-=In2S3+2（EDTA）3-（4）

2In2S3+9O2=2In2O3+6SO2（5）

EDTAisastrongcomplexagentandeasilyreactswithmetalions。

EDTAchemicalreaction

（1）wasthecomplexreactionandresultantwasIn（EDTA）.Thentheammoniaionizedtoprovideanalkalinecondition（reaction

（2））.CS（NH2）2caneasilyhydrolyzeinthealkalineconditionandthereaction（3）occurredtogenerateS2—ions.AreplacementreactionoccurredbetweenIn（EDTA）andS2-inreaction（4）,consequentlyformingtheprecursor.Theultrasonicdispersingandstirringprocessmadenano-clustersbeuniform。

TheprecursorIn2S3dispersedataformofnano—clusters.Ontheotherhand,EDTAhadstrongadsorbabilityanditwaseasytoconglomerate.WhenTeflon—linedstainlesssteelautoclaveprovidedahightemperatureandhighpressuresituation,someprecursorparticlesconglomeratedtogetherandformedsomesphericalandellipsestructurerowmaterialswithdifferentmagnitudesinthisexperiment。

Eventually,therowmaterialswerecalcinedandtheinnerorganicmattersbecamevaporsofCO2,SO2，andH2O,andtheIn2O3wasobtained（reaction（5））。

Thevaporswentintosurroundingairthroughsomeporecanalsintherowmaterial,whilewrinklesappearedonthesurfaceandformedflower-likeIn2O3material。

ThecompositeofIn2O3/CdOnanoparticles（amixtureofIn2O3andCdO）wasexaminedbyXRDasshowninFig。

4。

All