简介:RE-dopedNi-basedcatalystswerepreparedbysol-gelmethod.ThesecatalystswereappliedtothereactionofCO2reformingCH4tosyngas.ThestudiesrevealthatRE-doped(RE=La,Ce,Sm,Yb)Ni-basedcatalystsshowhighercatalyticactivitythanundopedNi-basedcatalyst,andwiththeincreasingofRE-dopedquantity,thecatalyticactivityofcatalystsexhibitsregularchanges.WhenRE-dopedquantityis0.2%(molarratio),thecatalystsshowthebestcatalyticactivity.
简介:混合氧化物(Ce0.6Zr0.4O2)由帮助微波的加热一起沉淀准备了的CeO2-ZrO2被用作支持经由早期湿的受精的方法与各种各样的CuO内容(0wt.%15wt.%)准备一系列CuO/Ce0.6Zr0.4O2催化剂。获得的CuO/Ce0.6Zr0.4O2样品被N2吸附,XRD,拉曼,TEM和H2-TPR技术,和他们的催化活动描绘因为公司氧化被调查。结果证明CuO/Ce0.6Zr0.4O2催化剂的活动被CuO的内容强烈影响,并且有10wt.%CuO的催化剂在公司氧化展出了最好的催化活动,它能在催化剂被归因于CuO,和高氧空缺集中的高分散和reducibility。
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:DirectextractionofmetalsfromsolidswithcomplexingagentsinsupercriticalCO2(SC-CO2)hasrecentlyattractedinterestsinseparation,purification,recovery,andanalysisofmetals.Inthepresentstudy,thestatic/dynamicextractionofrareearthelements(Nd,Ce)fromtheiroxides(Nd2O3,CeO2)withorganophosphoruscomplexeswithHNO3andH2OinSC-CO2wasinvestigated.ThestaticextractionefficiencyofNdfromNd2O3withthetri-n-butylphosphate(TBP)-HNO3complexcouldreach95%underoptimizedexperiment...
简介:SinglephaseofBa1-xMgAl10O17:xEu2+(0.02≤x≤0.14)phosphorswasfirstsuccessfullypreparedbyco-precipitationinaqueousmediumwitha'reversestrike'method,usingoxalicacidandammoniatogetherasprecipitants.Completelycrystallizedphosphorswereobtainedat1300℃,whichis300℃lowerthanthetemperatureofsolid-statereaction.TheirphotoluminescencewasinvestigatedunderUVandVUVregion,respectively.TheemissionspectraofBa1-xMgAl10O17:xEu2+samplesexcitedby254or147nmshowedacharacteristicwidebandwiththepeakcentredatabout450~454nm.Optimumemissionintensityreachedatx=0.1andthenconcentrationquenchingoccurred.Thesynthesizedphosphorshows10%higheremissionintensitythanthatpreparedbysolid-statereaction.
简介:一系列Ni-CeO2催化剂被一起沉淀方法与Na2CO3准备,NaOH,并且混合急躁(Na2CO3:NaOH;1:1比率)同样急躁分别地。催化表演上的precipitants的效果,Ni-CeO2催化剂的物理、化学的性质在X光检查的帮助下被调查衍射(XRD),Brumauer-Emmett-Teller方法(赌注),Fourier变换红外线的光谱学(英尺红外),thermogravimetry(TG),和H2-TPR描述。Ni-CeO2催化剂为反向的水气体移动反应关于他们的催化表演被检验,并且他们的催化活动是被评价:Ni-CeO2-CP(Na2CO3:NaOH=1:1)>Ni-CeO2-CP(Na2CO3)>Ni-CeO2-CP(NaOH)。相关到特征结果,催化剂由一起沉淀准备了与,这被发现混合急躁(Na2CO3:NaOH;1:1比率)同样急躁氧空缺的大多数数量与高度驱散的Ni粒子伴随了,它做了相应Ni-CeO2-CP(Na2CO3:NaOH=1:1)催化剂展览最高催化的活动。当时Na2CO3或NaOH急躁在Ni-CeO2催化剂导致了更少或没有氧空缺。作为结果,Ni-CeO2-CP(Na2CO3)和Ni-CeO2-CP(NaOH),催化剂介绍了差的催化性能。
简介:TheNd60Fe20Al8Co10B2alloywaspreparedbysuctioncastingofthemoltenalloyintoacoppermoldunderargonatmosphere.Themicro-structuralandmagneticpropertychangesintheNd60Fe20Al8Co10B2alloyduringcrystallizationwereinvestigatedbyX-raydiffraction(XRD),differentialscanningcalorimetry(DSC),scanningelectronmicroscope(SEM)andthevibratingsamplemagnetometer(VSM).TheprecipitationandNd-richandFe-richphaseshavenosignificanteffectontheintrinsiccoercitityforNd60Fe20Al8Co10B2alloyannealedbelow723K.However,thegrowthofFe-richphasedecreasesthesaturatemagnetizationandremanenceofthealloy.Thehardmagneticbehaviorisdisappearedwhenthealloyisfullycrystallized.
简介:Thesynthesisofprecursorofgreenphosphors,LaPO4:Ce,Tb,bymeansofco-precipitationwithcocurrentflowfeedwasstudied.Theeffectsofthereactiontemperature,thekindandconcentrationoftheacidinthebottomwater,andthechargingrateonthephysicalproperties,suchasparticlesize,wereinvestigated.Itisfoundthattheparticlesizeofthepowderiscontrollablebyadjustingacidityinbottomwaterandchargingrate.Thepowderwithdiametersizeof3to5μmwasobtained.ItsXRDandSEMwereanalyzed.XRDpatternsoftheas-preparedgreenphosphorpowdersdisplaythetypicalpeaksofCePO4.SEMshowsthatthemorphologyofpowdersisball-shaped.
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简介:BondedtypeRE3+dopedluminescentco-polymerwassynthesizedbysolutionfreeradicalcopolymerization.Theinfluenceofchargesequence,monomersandco-polymerizedmethodonpropertiesandstructuresoftheco-polymerswasstudied.Theemissionintensityoftheco-polymersatdifferentRE3+concentrationswastested.Theresultsshowedthattheco-polymersofEu-PStandEu-PMMAbothhadwideabsorptionpeakat200-400nmandthestrongestpeakappearedat235nm.ThefluorescentintensityofEu3+dopedpolystyreneco-polymerwasstrongerthanthatofEu3+dopedPMMAcopolymer.Thecharacteristicemissionofeuropiumionswasobservedintheco-polymers.Thecopolymerdopedwithrareearthelementsshowedthe"sensitizationeffect"forthecentralions.Thebonded-typerareearthcopolymernotonlyenhancedtheenergytransferefficiency,butalsoimprovedthefluorescenceintensitybyiacreasmgtherigidityofmainandsidechain.
简介:YAG:Ce3+(Yttriumaluminumgarnet)fluorescencepowdersweresuccessfullypreparedbyco-precipitationmethodusingaluminumnitrate,yttriumnitrate,cerousnitrateasthestartingmaterialsandammoniumcarbonateasprecipitant.TheproductswerecharacterizedbyX-raypowderdiffraction,luminescencespectrometer,transmissionelectronmicroscope(TEM).TheXRDresultsshowedthattheobtainedYAG:Ce3+fluorescencepowdershadthecrystallinestructuresofYAGatcalcinationstemperatureof900oCandtheTEMresultsshowedthatthegraindiameterswereabout100nm.TheYAG:Ce3+fluorescencepowders,synthesizedbyco-precipitationmethod,hadthebestluminescencepropertywhentheCedopingamountwasx=0.06inthemolecularformulaofY3-xCexAl5O12,thecalcinationstimewas2handthecalcinationstemperaturewas1000°C.
简介:Eu-activatedCaMoO4phosphorswereco-precipitatedinanaqueoussolution,andNH3·H2O,NH4HCO3and(NH2)2COaspre-cipitatingaidagentswerecomparedbasedonthemorphologyandparticlesizedistributionofthephosphorsamples.Sm3+assensitizerionwasinvestigatedontheluminescenceofCaMoO4:Eu,anditcouldstrengthenthe406nmabsorptionofthisphosphor.Atlast,thescheeliteCaMoO4:EuandwolframiteZnMoO4:Euwereselectedtocomparetheirhostabsorption.TheresultshowedthatthescheelitemolybdatehostexhibitedstrongerUVabsorptionthanwolframiteone.