简介:Metal-organicframeworks(MOFs)haveattractedmuchattentionasadsorbentsfortheseparationofCO2fromfluegasornaturalgas.Here,atypicalmetal-organicframeworkHKUST-1(alsonamedCu-BTCorMOF-199)waschemicallyreducedbydopingitwithalkalimetals(Li,NaandK)andtheywerefurtherusedtoinvestigatetheirCO2adsorptioncapacities.Thestructuralinformation,surfacechemistryandthermalbehaviorofthepreparedadsorbentsampleswerecharacterizedbyX-raypowderdiffraction(XRD),thermo-gravimetricanalysis(TGA)andnitrogenadsorption-desorptionisothermanalysis.TheresultsshowedthattheCO2storagecapacityofHKUST-1dopedwithmoderatequantitiesofLi+,Na+andK+,individually,wasgreaterthanthatofunmodifiedHKUST-1.ThehighestCO2adsorptionuptakeof8.64mmol/gwasobtainedwith1K-HKUST-1,anditwasca.11%increaseinadsorptioncapacityat298Kand18barascomparedwithHKUST-1.Moreover,adsorptiontestsshowedthatHKUST-1and1K-HKUST-1displayedmuchhigheradsorptioncapacitiesofCO2thanthoseofN2.Finally,theadsorption/desorptioncycleexperimentrevealedthattheadsorptionperformanceof1K-HKUST-1wasfairlystable,withoutobviousdeteriorationintheadsorptioncapacityofCO2after10cycles.
简介:Thesteadyanddynamicpropertiesarecomparativelyinvestigatedforthen-dopedandnon-dopedInGaNLEDs.Thesimulatedresultsshowthatthen-dopedLEDexhibitsthesuperiorluminescenceandmodulationperformance,whichismainlyattributedtothehighercarrierradiativerateofn-dopedLED.Theresultscanexplainthereportedexperimentalresultsperfectly.
简介:稀罕做地球的铜锰混合了氧化物催化剂被一起沉淀并且用铜硫酸盐,锰硫酸盐,和稀土元素的氧化物REO的机械混合准备(REO显示La2O3,CeO2,Y2O3,或Pr6O11)作为原料。样品被X光检查描绘衍射(XRD),规划温度的减小(TPR),氧化表面(s-TPR)的规划温度的减小,和规划温度的解吸附作用(TPD)。催化活动为水气体移动反应被测试。做稀土元素氧化物没改变原来的铜锰的水晶结构混合了氧化物,但是改变了interplanar间距,吸附表演和反应性能。与La2O3提高了这项活动,因为高铜分发和好减小,Cu-Mn的稳定性混合了氧化物。与CeO2和Y2O3也减少了到不同的度的样品的减小温度当在表面上改进Cu的分散时,这样,催化活动比undopedCu-Mn的好样品。Pr6O11-doped样品是困难的减少,表面铜的分散被降低,导致穷人活动。
简介:Dopingeffectsofmanganese(Mn)oncatalyticperformanceandstructureevolutionofNiMgOcatalystsforsynthesisofmulti-walledcarbonnanotubes(MWCNTs)frommethanewereinvestigatedforthefirsttime.AdditionofMninNiMgOcatalystcangreatlyimprovetheMWCNTsyield.Mn0.2NiMgOcatalystamongthetestedonesgivesthehighestMWCNTsyieldas2244%,whichistwotimeshigherthanthatofthecatalystwithoutMn.Thestructureevolution,reductionbehaviorsandsurfacechemicalpropertiesofMnNiMgOcatalystswithvariousMncontentswerestudiedindetail.ItwasfoundthatthestablesolidsolutionofNiMgO2formedinNiMgOcatalystwasdisturbedbytheadditionofMn.Instead,anothersolidsolutionofMnMg6O8isformed.MoreamountofNicanbereducedanddispersedonthecatalystsurfacetobeactedasactivesites.Importantly,thechangesofNicontentonthesurfacearecorrelatedwiththeNiparticlesizeandtheouterdiameterofMWCNTs,suggestingthecontrollablesynthesisofMWCNTsoverMnNiMgOcatalysts.
简介:Ba0.85Ca0.15Ti0.9Zr0.1O3(BCTZ)lead-freepiezoelectricceramicsco-dopedwithCeO2(x=0.1wt.%,0.2wt.%,0.3wt.%,0.4wt.%,0.5wt.%)andLi2CO3(0.6wt.%)werepreparedbyconventionalsolid-statereactionmethod.InfluenceofCeO2dopingamountonthepiezoelectricproperties,dielectricproperties,phasecompositionandmicrostructureofpreparedBCTZlead-freepiezoelectricceramicsdopedwithLi2CO3wereinvestigatedbyX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM)andotheranalyticalmethods.TheresultsshowedthatthesinteredtemperatureofBCTZlead-freepiezoelectricceramicsdopedwithCeO2decreasedgreatlywhenLi2CO3dopingamountwas0.6wt.%;apureperovskitestructureofBCTZlead-freepiezoelectricceramicsco-dopedwithLi2CO3andCeO2andsinteredat1050°Ccouldalsobeobtained.Thepiezoelectricconstant(d33),therelativepermittivity(εr)andtheplanarelectromechanicalcouplingfactor(kp)ofBCTZceramicsdopedwithLi2CO3increasedfirstlyandthendecreased,thedielectricloss(tanδ)decreasedfirstlyandthenincreasedanddecreasedatlastwhenCeO2dopingamountincreased.TheinfluenceofCeO2dopingonthepropertiesofBCTZlead-freepiezoelectricceramicsdopedwithLi2CO3werecausedby'softeffect'and'hardeffect'piezoelectricadditiveandcausinglatticedistortion.WhenCeO2dopingamount(x)was0.2wt.%,theBCTZceramicsdopedwithLi2CO3(0.6wt.%)andsinteredat1050°Cpossessedthebestpiezoelectricpropertyanddielectricpropertywithd33of436pC/N,kpof48.3%,εrof3650,tanδof1.5%.