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:AseriesofSm~(3+)dopedY_2MoO_6werepreparedthroughhightemperaturesolidstatereactiontechnique.Theirphasestructures,morphologiesandluminescencepropertieswereinvestigatedbyX-raydiffraction(XRD),scanningelectronmicroscopy(SEM)andphotoluminescencespectrometry.ThemostintenseabsorptionofY_2MoO_6hostoccurredat367nm.EnergytransferfromhostlatticetoSm~(3+)ionscouldbeobserved,andtheschematicdiagramofenergytransferwasconstructed.ThecriticalenergytransferdistanceandenergytransfermechanismbetweenSm~(3+)ionswerediscussedindetail.Consideringthehighcolorpurityandappropriateemissionintensity,Sm~(3+)dopedY_2MoO_6couldbeapromisingphosphorundernearultravioletlightexcitation.
简介:TheinfluenceofrareearthoxideCeO2onmicrostructureandwearresistanceofM80S20thermalsprayandthermalsprayweldingcoatingsisstudiedusingopticalmicroscope,scanningelectronmicroscope,X-rayenergydispersionspectroscope,X-raydiffractometerandweartestingmachine.Theresultsshowthattheaddi-tionof8%CeO2canimprovethemicrostructure,microhardnessandwearresistanceofcoatingssignificantly.
简介:Er3+/Yb3+codopedzincateBaGd2ZnO5phosphorsweresynthesizedviaatraditionalsolidstatereaction.ThecrystalstructureandphasepuritywerecheckedbymeansofX-raydiffraction(XRD),andtheresultsshowedthatpurephaseBaGd2ZnO5phosphorswithvariousEr3+,Yb3+concentrationswereobtained.TheinfluenceofEr3+andYb3+dopingconcentrationsonthegreenandredupconversionemissionswasstudied.Itwasfoundthatbothgreenandredupconversionemissionsunder980nmexcitationweretwo-photonprocessesindependentfromtherareearthdopingconcentrations.However,theupconversionluminescenceintensitiesgreatlydependedontherareearthdopingconcentration.Furthermore,thepopulationprocessesofupconversionluminescenceandthequenchingmechanismswereanalyzed.Thetemperature-dependentgreenupconversionluminescencewasstudied,andthetemperaturequenchingprocessoftwogreenupconversionemissionswasmodeled.Thethermalquenchingprocessesofthegreenupconversionemissionscouldbewellexplainedbythemodelweproposed.
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:DifferentphasesofMg-Li-SmalloyswerepreparedbygalvanostaticelectrolysisinLiCl-KCl-MgCl2-SmCl3meltsat670°C.TheelectrolysisprocessandphasecontrolofMg-Li-Smalloyswerestudied.Themicrostructuresofα,α+β,βphasesofMg-Li-SmalloyswerecharacterizedbyX-raydiffraction(XRD)andopticalmicroscope(OM).Analysisofscanningelectronmicroscopy(SEM)andEDSmappinganalysisshowedthatMgdistributedhomogeneouslyinMg-Li-Smalloys.EDSresultshowedthatthedistributionofSmwasmoreat...
简介:高度取向附生、纯(001)面向的CeO2电影被激光在SrTiO3(001)底层上种没有任何气体的分子的横梁取向附生方法周围。CeO2的Layer-by-layer取向附生的生长模式被证实由在situ思考高精力的电子衍射(RHEED)观察。高分辨率的X光检查衍射(HRXRD)和高分辨率的传播电子显微镜学(HRTEM)结果显示了STO(100)//CeO2(100),STO[100]//CeO2[110]为out-of-plane和在里面飞机的取向附生的关系分别地。取向附生的电影的形成机制也根据一个理论模型被讨论。LMBEceria电影的化学状态被评估并且证实因为Ce3+和氧空缺的存在被介绍。
简介:Semi-solidAl2Y/AZ91magnesiummatrixcompositesslurrywaspreparedbyultrasonicvibration,effectofultrasonicvibrationtemperatureandtimeonmicrostructureofsemi-solidslurrywasinvestigated.Theresultsshowedthatwiththeultrasonicvibrationtemperaturedecreasingthesolidvolumefractionofsemi-solidslurryincreased.Thebestultrasonicvibrationtemperaturewas600oC.Withtheincreaseofultrasonicvibrationtime,theaveragegraindiameterofprimaryа-Mgparticlesdecreasedfirstly,thenincreased,theaverageshapefactorincreasedgraduallyanddecreasedslightlyafter90s,andafewrosettedendriteswereobservedafter120s.Thebestsemi-solidslurrywithaveragegraindiameterof75μmandshapefactorof0.7weregainedafterthemeltwastreatedbyultrasonicvibrationforabout60satnearliquidustemperature(600oC).Atlast,themicrostructureevolutionmechanismofsemi-solidmagnesiummatrixcompositesslurrywasanalyzedbythetheoriesofthermodynamicsandkinetics.
简介:有一致形态学的新奇红射出的K2(Ge,Si)F6:Mn4+黄磷被一起沉淀方法综合。纯K2有P636阶段>除P3m1空间组以外的mc空间组就被Si的加入在K2在房间温度的GeF6根据XRD描述。薄片状的显示出的SEM图象和为K2GeF6:Mn4+和K2(Ge,Si)F6:Mn4+黄磷分别地。光致发光刺激(PLE)和光致发光(PL)在K2GeF6:Mn4+和K2(Ge,Si)F6:Mn4+系统。并且K2有Si的GeF6:Mn4+显示出一座强壮的山峰。同时水晶的地包围Mn4+变化能在这个氟化物系统影响腐烂时间。带的设备的颜色范围基于K2(Ge,Si)F6:Mn4+和K2分别地,GeF6:Mn4+到达了多达94.58%NTSC(国家电视标准委员会)和94.386%NTSC那基于氮化物红黄磷比那高得多。在K2(Ge,Si)F6:Mn4+黄磷的所有这些原来的特征作为为改善灯光和常规白LEDs的显示质量的红黄磷为潜在的应用是合乎需要的。
简介:PolycrystallineGd2(MoO4)3:Dy3+phosphorshavebeensynthesizedbyhightemperaturesolid-statereactionmethod.ThephosphorswerecharacterizedwithX-raydiffractometer,thermogravimetricanalysisanddifferentscanningcalorimeter,scanningelectronmicroscopy,andphotoluminescencespectrofluorimeter.Severalpeaksat351,389,425,452,and472nmappearedinphotoluminescenceexcitationspectrum,whichmatchedwellwiththeemissionoftheultraviolet(UV)andblue-lightemittingdiode(LED)chips.Uponexcitationat389nmUVlight,intenseemissionscenteredat484,575and668nmwereattributedtothetransitionsof4F9/2→6H15/2,4F9/2→6H13/2and4F9/2→6H11/2ofDy3+,respectively.ThechromaticitycoordinatesandcorrelativecolortemperatureshavebeencalculatedandpresentedintheCommissionInternationaldeI'Eclairage(CIE)diagrams.TheresultsindicatedthatGd1.9(MoO4)3:Dy0.13+withCIEcoordinatesof(x=0.38,y=0.41)andthecorrelativecolortemperatureof4134KisapotentialcandidateforwhiteLEDs.
简介:TheNd60Fe20Al8Co10B2alloywaspreparedbysuctioncastingofthemoltenalloyintoacoppermoldunderargonatmosphere.Themicro-structuralandmagneticpropertychangesintheNd60Fe20Al8Co10B2alloyduringcrystallizationwereinvestigatedbyX-raydiffraction(XRD),differentialscanningcalorimetry(DSC),scanningelectronmicroscope(SEM)andthevibratingsamplemagnetometer(VSM).TheprecipitationandNd-richandFe-richphaseshavenosignificanteffectontheintrinsiccoercitityforNd60Fe20Al8Co10B2alloyannealedbelow723K.However,thegrowthofFe-richphasedecreasesthesaturatemagnetizationandremanenceofthealloy.Thehardmagneticbehaviorisdisappearedwhenthealloyisfullycrystallized.
简介:Pt-freecounterelectrode(CE)composedofLa2MoO6(La2O3-MoO3)wassuccessfullysynthesizedbysimplepyrolysisoflanthanumacetate(C6H9O6La·xH2O)andhexaammoniumheptamolybdatetetrahydrate((NH4)6Mo7O24·4H2O).Furthermore,threeproportionscompositescatalystsofLa2MoO6@MWCNTsbasedonLa2MoO6andmultiwallcarbonnanotubes(MWCNTs)werepreparedandcharacterizedasPtfreecatalystforCEindye-sensitizedsolarcells(DSSCs).ThemorphologyandstructureofLa2MoO6@MWCNTscompositesweredeterminedbyscanningelectronmicroscopy,transmissionelectronmicroscopeandX-raydiffraction.TheelectrochemicalperformanceofLa2MoO6@MWCNTscompositecatalystsforCEswasdeterminedbyphotocurrent-voltagemeasurements,cyclicvoltammetry,electrochemicalimpedancespectroscopy,andTafelpolarization.Thepowerconversionefficienciesof4.68%,4.87%and5.06%areobtainedforLa2MoO6:MWCNTswiththemassratiosof5:1,3:1and1:1towardsthereductionofI3-toI-underthesameconditions,respectively,whicharesuperiortothoseofMWCNTs(3,94%)andLa2MoO6(1.71%)electrodes.TheexperimentalresultsrevealthatthepresenceofMWCNTsresultsinanaugmentedactivecatalyticsurfaceareaandenhancedchargetransferfromCEtotheelectrolyte.
简介:Er~(3+)andLa~(3+)codopedY_2O_3nanocrystallinepowdersweresynthesizedbygelcombustionmethodandcharacterizedwiththermalanalysis,X-raydiffraction(XRD),transmissionelectronmicroscopy(TEM),high-resolutionTEM(HRTEM)techniquesandfluorescencespectroscopy.Afterbeingcalcinedat1200oC,the(Y_(1–x)La_x)_2O_3:Er~(3+)powderswereconfirmedtobecubicY_2O_3phasewiththecrystallinegrainsizeintherangeof20–40nm.TheEr~(3+)emissionat1.53μmfromthe~4I_(13/2)→~4I_(15/2)transitionwasobserved,whichwasfoundtobeenhancedbyintroducingLa~(3+)ions.SuchenhancementcouldbeattributedtotheadjustmentofEr~(3+)ions'localenvironmentbythecodopingofLa~(3+)ions,leadingtotheincreasedgroundstateabsorptioncrosssectionofEr~(3+)ions.