简介:Loadedonthecordierite,therareearthdopedcompositecatalystwaspreparedbysol-gelmethodcombinedwithdippingtechnique.TakingOrthodichlorobenzeneasmodel,thecatalystwasusedtoremovethedioxinsofthewastegas.Theresultsshowedthatat280℃andgasspacevelocitybeing8000h-1,theorthodichlorobenzenecouldberemovedeffectivilybythepreparedCeO2-TiO2-V2O5compositecatalystwhoseactivitywasremarkablyenhancedbythedopingofCe,whiletheindustrialside-streamtestofdioxinsfromrefuseincinerationsmokeindicatedthatthedecompositionratecouldreachabove93%underthesameconditions.
简介:Inthiswork,boththethermalexpansionandelectricalconductivityofnanocrystallineLa2Mo2O9werestudied.ThenanocrystallinepowderofLa2Mo2O9wasobtainedbysol-gelmethod,andwiththehelpofSHP(superhighpressure)upto4.5×104atmat700℃forashorttime,andthenanocrystallinepowderwasdensifiedwithoutobviousparticlesizegrowth.TheelectricalconductivityofnanocrystallineLa2Mo2O9wasoneorderofmagnitudelowerthanthatofthemicrocrystallinesampleatthesametemperature.Owingtothephasetransition,themicrocrystallineLa2Mo2O9hasanabruptincreaseofthermalexpansionwithapeakvalueof48×10-6K-1at556℃.Forthenanocrystallinematerial,thepeakvalueincreasesto112×10-6K-1at520℃.Ontheotherhand,above600℃thesignificantgrowthofparticlesizeofthenanocrystallineLa2Mo2O9wasobserved,accompanyingbyatremendousincreaseofthermalexpansionwithapeakvalueofthirdhigherthanthatofLa2Mo2O9.
简介:Basedonthethermodynamicallyself-consistentanalysisandoptimizationofthreesub-binarysystemsoftheternarysystemPrCl3-CaCl2-MgCl2,thethermodynamicsofthisternarysystemhasbeenstudied.UsingHillertmodelandtakingMgCl2asanasymmetriccomponent,thePrCl3-CaCl2-MgCl2phasediagramhasbeencalculated.Theagreementbetweencalculatedandmeasuredcompositionsandtemperaturesatdeflectingpointsonliquidusisgood.Thesystemisasimpleeutecticonewithaeutecticpointat26.0mol%PrCl3,41.5mol%CaCl2,32.5mol%MgCl2;560℃(calculated)and26.0mol%PrCl3,39.4mol%CaCl2,34.6mol%MgCl2;546℃(measured),respectively.
简介:TheZrO2-Al2O3ceramiccompositeswerepreparedbyappropriatetechniqueswithcommercialZrO2andAl2O3powdersasrawmaterialsandY2O3asstabilizer.TheresultsindicatethatwiththeintroductionofAl2O3intotheZrO2matrixwherethequantityofadditiveY2O3is3.5%(molefraction),thegrowthofZrO2grainsisefficientlyinhibited,whichhelpstheZrO2grainsexistinametastabletetragonalmanner;thushigherstrengthandtoughnessareacquired.Whenthecontentofaluminais20%(massfraction),thebendingstrengthandfracturetoughnessofthecompositesare676.7MPaand10MPa·m1/2respectively,themechanicalbehaviorsareclosetothosepreparedwithZrO2andAl2O3powderssynthesizedthroughwetchemicalapproach.Themechanicalbehaviorsofthecompositesarewellimprovedowingtothedispersiontougheningofaluminagrainsandphasetransformationtougheningofzirconiagrains.
简介:Differentrareearth(RE)ionsdopantswereaddedintotheSrAl2SiO7:Eu2+phosphorsinordertoenhancethephosphorescenceproperties,andtheeffectoftheREionsincludingYb3+,Ce3+,Nd3+,Dy3+andTm3+,wascomparativelyinvestigated.ItwasfoundthatNd3+additionimprovedthephosphorescencepropertiesobviouslyamongallthestudiedREions.Therefore,Sr1.96–xAl2SiO7:xEu2+,yNd3+phosphorswerestudiedindetail,andtheoptimumEu2+andNd3+concentrationsweredeterminedwiththeafterglowtimeofabout20min.Thephasestructures,photoluminescence(PL)properties,long-lastingphosphorescence(LLP)properties,afterglowdecaycurvesandthermo-luminescence(TL)fortheselectedphosphorsduringthecorrespondingstudywereinvestigated.AllthephosphorsexhibitedgreenPLemissionandLLPemission.ThereweretwoTLbandslocatedatabout325and380Kforthestudiedsamples,andtherelationshipbetweenREadditionandphosphorescencepropertieswasdiscussed.
简介:FluorescencespectraofSm2+andEu2+→Sm2+energytransferwerestudiedinSrB4O7.Thereappearsonlyfluorescencefrom5D0transitionofSm2+at77K.Thevibroniclinesassociatedwith5D0→7F0transitionwereobserved.Thethermalpopulationtoupperstatesof5D1and4f5dlevelsfrom5D0givesriseto5D1→7FJand5d→4fradiativetransitionsofSin2+athighertemperature.
简介:Reactionof(MeC5H4)3LnwithHOCH2CH2NMe2intetrahydrofuran(THF)givesthenewcomplexes[(MeC5H4)2Ln(μ-OCH2CH2NMe2)]2(Ln=Sm,Y,Nd)withnitrogenfunctionalizedμ-alkoxideligand.ThecomplexeswerecharacterizedbyelementalanalysisandIR,and[(MeC5H4)2Sm(μ-OCH2CH2NMe2)]2wasstructurallycharacterizedbytheX-raydiffractiontobeadimerformedbytwounsymmetricoxygenbridges.ThecomplexhasatricyclicskeletonwiththeadditionaltwoSm-NbondsviaintramolecularcoordinationofOCH2CH2NMe2.ThecoordinationnumberofthecentralmetalSmisnine.Thetitlecomplexesshowgoodcatalyticactivityforring-openingpolymerizationofε-caprolactone.
简介:增加的CeO2(ZrO2)/TiO2催化剂独立由大音阶的第五音胶化和受精的方法准备了的一系列镨为选择催化减小被测试没有,并且由X光检查衍射(XRD)描绘了,N2-brumauer-emmett-teller(N2-BET),NH3-temperature规划了解吸附作用(NH3-TPD),H2-temperature规划了减小(H2-TPR),PL系列,拉曼系列,电子顺磁的回声(EPR)一催化性能上的准备方法的影响被学习。结果证明CeO2(ZrO2)/TiO2催化剂的催化性能上的Pr增加的影响在大音阶的第五音胶化方法和受精方法之间是不同的。Pr增加趋于与TiO2交往并且当它是更可能的与在受精方法形成Ce-O-Pr的结构的CeO2交往时,在大音阶的第五音胶化方法形成了Ti-O-Pr的结构。大音阶的第五音胶化方法准备的催化剂的全部的酸数量和氧化还原作用性质与Pr元素的增加减少了,它导致了催化活动的减少。相反,受精方法准备的增加Pr的催化剂被发现拥有更容易的reducibility,更多的全部的酸数量和Ce3+种类的更高的比例,它为更高催化的活动是赞成的。
简介:在甲烷(POM)的部分氧化的催化活动和稳定性混合方法的CeO2-ZrO2和-Al2O3的影响在Ni/Ce0.7Zr0.3O2-Al2O3催化剂上被调查。催化剂被XRD,TPR,H2-chemsorption,和TG-DTA描绘。为新鲜催化剂,结果证明混合催化剂(原子)的盐先锋比混合方法(摩尔)和机械地混合方法(MECH)的粉末的催促的人准备的催化剂介绍了更好的性能。XRD的结果建议在在原子样品的CeO2-ZrO2和Al2O3之间的相互作用比其它强壮,它导致了更多的格子缺点和从而更好的起始的活动。而且,MECH样品在24h稳定性测试有最好的稳定性和最少的焦炭免职。TPR和H2-chemsorption的结果显示在MECH样品的Ni-Al的亲密接触提高了抵抗焦炭免职和金属sintering的能力。
简介:Inthispaper,varioustechniquesincludingBET,XRD,SEMandXPSwereusedtostudythesinteringofpureandLa2O3-dopedtitania.Theexperimentalresultsshowthatsinteringoftitaniaproceedsviavolumediffu-sion.Addingoflanthanumoxidedecreasestherateofsinteringandhindersthephasetransitionfromanatasetorutilecrystalbystrongsurfaceinteractionbetweenthemixedcrystals(La4Ti9O24,La0.66TiO2.99)andTiO2.
简介:Ni-W-P-CeO2-SiO2nano-compositecoatingswerepreparedonthecarbonsteelsurfacebypulseco-depositionofnickel,tungsten,phosphorus,nano-CeO2andnano-SiO2particles.Theinfluenceofnano-SiO2particlesconcentrationsinelectrolyteonmicrostructuresandpropertiesofthenano-compositecoatingswereresearched,andthecharacteristicswereassessedbychemicalcompositions,elementdistribution,depositionrate,microhardnessandmicrostructures.Theresultsindicatethatwhennano-SiO2particlesconcentrationsinelectrolytearecontrolledat20g·L-1,thedepositionratewith27.07μm·h-1andthemicrohardnesswith666Hvofthenano-compositecoatingsarehighest,elementlinescanningandareascanninganalysesshowthattheaveragecontentsofelementsW,P,SiandCeinthenano-compositecoatingsareclose,displayingthatthedistributionofeveryelementwithinthenano-compositecoatingsiseven.Anincreaseinnano-SiO2particlesconcentrationsinelectrolyte(whenlowerthan20g·L-1)leadstorefinementingrainstructureofnano-compositecoatings,butwhenitimprovedto30g·L-1,thecrystallitesizesincreaseagainandinthemeantimetherearealotofsmallbosswithnodulationshapeappearingonthesurfaceofnano-compositecoatings.
简介:Ca8Mg(SiO4)4Cl2:Eu2+phosphordopedwithSr2+cationforCa2+partially,wassynthesizedbysolid-statereactionathightemperatureunderreducingatmosphere,anditsluminescentpropertieswereinvestigated.TheexperimentalresultsindicatethattheemissionintensityofthephosphorincreasesafterbeingdopedwithafewamountofSr2+ion.Theemissionpeakofthephosphorblueshifttoabout464nmwhenthephosphorisdopedwithlargequantityofSr2+ions.TheexcitationspectrumindicatesthatthephosphorcanbewellexcitedbyUVandbluelightfrom300to460nm,andthephosphorwasfittedwellfortheexcitationbyUVorblue-LED.
简介:CeZr,CeYZr,LaCeZr,LaCePrZr,LaCePrYZr,和LaCePr稳固的答案经由一起沉淀方法被准备,并且借助于X光检查衍射(XRD)和Brunauer-Emmett-Teller(赌注)技术描绘了。稳固的答案的氧存储能力(振荡)被脉搏技术评估,催化活动用一台4隧道催化作用设备被估计。稳固的答案介绍了立方的结构,这被看见。特定的表面区域和热稳定性能被做Y进稳固的答案提高。当做大量La减少了时,做La的小数量在热耐久性上有积极效果特定的表面区域和热稳定性。LaCePrZr和LaCePrYZr固体解决方案用在Nd抽取在特定的表面区域和热稳定性介绍了某个更高的值以后,与LaCePr充实的Baotou稀土元素矿物质残余综合了,当为汽车的经济催化剂用尽纯化,从而启用被过去常。ceria氧化锆固体答案的表面上的涂层Al2O3或SiO2层增加了特定的表面区域和热抵抗。
简介:Ca-dopedBaMgAl10O17:Eu2+,Mn2+(BAM)bluephosphorsweresynthesizedbyfluxassistedsolid-statereactionmethodusingCaF2andBaF2asco-flux.GooddispersityandparticlesizehomogenizationofhexagonalpurephaseBAMwereobtainedbysinteringat1400℃.TheeffectsoftheCa2+ionscontentonthestructure,morphologyandphotoluminescencepropertiesofthephosphorswerestudied.TheresultsindicatedthattheincorporationofCacoulddecreasethelatticeconstant,improvethehomogeneityanddispersityandenhancethephotoluminescence(PL)intensityofthephosphoreffectively.TheoptimumBa0.86Ca0.04Mg0.97Al10O17:0.1Eu2+,0.03Mn2+PLintensitywasenhancedforabout30%andrelativebrightnesswasimprovedabout4%.Furthermore,thesynthesizedBAMandcommercialBAMphosphorswereannealedfor30minat600oCinair.TheCa-dopedphosphorshadstrongeremissionintensity,higherbrightnessandbetterchromaticitystabilitythanthatofthecommercialphosphor.TheseresultsindicatedthatCa-dopedbluephosphorshadgoodpotentialapplicationsinthecommercialtricolorfluorescentlampsaswellasinotherdisplayandlamps.
简介:AseriesofCe0.5Fe0.30Zr0.20O2catalystswerepreparedbydifferentmethods(co-precipitationsmethod,citricacidsol-gelmethod,impregnationmethod,physicalmixedmethod,andhydrothermalmethod)andcharacterizedbyX-raydiffraction(XRD),Ramanspectroscopy,Brunauer-Emmett-Teller(BET)andH2-TPRmeasurements.Potentialofthecatalystsinthesootoxidationwasevaluatedinatemperature-programmedoxidation(TPO)apparatus.TheresultsshowedthatalltheFe3+andZr4+wereincorporatedintocerialatticetoformapureCe-Fe-Zr-Osolidsolutionfortheco-precipitationsample,buttwokindsofFephasesexistedintheCe-Fe-Zr-Ocatalystspreparedbyothermethods:Fe3+incorporatedintoCeO2latticeanddispersedFe2O3clusters.ThefreeFe2O3clusterscouldimprovetheactivityofcatalystsforsootoxidationcomparingwiththepureCe-Fe-Zr-OsolidsolutionowingtothesynergeticeffectbetweenfreeFe2O3andsurfaceoxygenvacancies.Inaddition,theactivityofcatalystsstronglyreliedonthesurfacereducibilityoffreeFe2O3particles.HoldingbothabundantfreeFe2O3particlesandhighoxygenvacancyconcentration,thehydrothermalCe0.5Fe0.3Zr0.2O2catalystpresentedthelowestTi(251°C,ignitiontemperatureofsootoxidation)andTm(310°C,maximumoxidationratetemperature)forsootcombustion(withtight-contactbetweensootandcatalysts)amongthefivesamples.Evenafteragingat800°Cfor10h,theTiandTmwerestillrelativelylow,at273and361°C,respectively,indicatinghighcatalyticstability.