简介:TwonovelwashcoatsCe0.8Zr0.15La0.05OδandCe0.8Zr0.2O2waspreparedbyanimpregnationmethod,whichactedasahostfortheactivePdcomponenttopreparePd/Ce0.8Zr0.15La0.05Oδ/substrateandPd/Ce0.8Zr0.2O2/substratemonolithiccatalystsfortoluenecombustion.ThewashcoatswascharacterizedbyX-raydiffraction(XRD),Ramanspectroscopy,Brunauner-Emmett-Teller(BET),andH2-temperature-programmedreduction(H2-TPR).Theresultindicatedthatboththewashcoatshadstrongvibration-shockresistanceaccordingtoultrasonictest.DopingLa3+intoCeO2-ZrO2solidsolutioncouldgeneratemoreoxygenvacancies,andcouldinhibitthesinterofCeO2-ZrO2solidsolutionwhencalcinedathightemperatures(800,900and1000°C).ThewashcoatCe0.8Zr0.15La0.05Oδhadmuchbetterredoxproperties.ThereductivetemperatureofCe4+speciesshiftedtolowtemperatureby60°Cwhenthewashcoatscalcinedathightemperatures(800,900and1000°C).ThePd/Ce0.8Zr0.15La0.05Oδ/substratemonolithiccatalystcalcinationat500°Chadthebestcatalyticactivityandthe95%tolueneconversionatatemperatureaslowas190°C.Whencalcinedatlowtemperature(500and700°C),thecatalyticactivityhaslittleimprovement,however,whencalcinedathightemperature,thecatalyticactivityofPd/Ce0.8Zr0.15La0.05Oδ/substratemonolithiccatalystshadsignificantimprovement.Ascatalystwashcoat,theCe0.8Zr0.15La0.05OδhadbetterthermalstabilitythanthewashcoatCe0.8Zr0.2O2,thedevelopedPd/Ce0.8Zr0.15La0.05Oδ/substratemonolithiccatalystinthisworkwaspromisingforeliminatingVolatileorganiccompounds.
简介:Duetotheremarkablemagnetoresistance(MR)effectonperovskite-typemanganite,magnetoelectronicsandspintronicshavebecomeattractivesubjectsofexperimentalandtheoreticalinvestigationsfortheapplicationpurpose.(La0.9Nd0.1)2/3Ca1/3Mn1-xFexO3(x=0,x=0.05)werepreparedsuccessfullybysol-gelmethod.Thestructure,magneticproperties,andtransportpropertiesofthecompoundswereinvestigated.Themagnetoresistanceeffectdependsonthecompositionandthetemperature.XRDpatternsshowthatthecompoundisasinglephasepolycrystalwithpseudocubicstructure.Alargenegativeisotropicmagnetoresistanceeffectinthesampleswereobservedatlowtemperatureregion.ThemaximumMRofthesampleswas77%and97%,respectively.Itwasmostlikelyduetothescatteringorthetunnelingtransportofspin-polarizedcarriersinlatticeunderstrongmagneticfield.
简介:ThechemicalstateofgrainboundarycosegregationofCeandPinFe-P-CealloysystemwasstudiedbymeansofAugerElectronSpectroscopy(AES).TheAugerpeaksofCesegregatedatgrainboundariesarefoundwithintherangeof60~180eV.BycomparingwiththeAugerspectraoftheFe-Ce-Pintermetalliccompound,itissupposedthatthereisatwo-dimensionalinterfacialphaseatgrainboundarieswithCeandPcosegregationwhichissimilartothestructureoftheFe-Ce-Pcompound.