简介:Inthispaper,MPt/C(M=La,Nd)catalystsofPEMFCweresynthesizedbymicrowaveradiationprocess.ThecrystallinityandstructureofcatalystswererespectivelyanalyzedbyXRDandnitrogenadsorptiontests.Theactivityofcatalystswasinvestigatedbyelectrochemistryexperiment.Theresultsshowedthat:1)comparedwithPt/Ccatalystpreparedbytypicalimpregnation-reductionprocess,thesizeofMPt/CcatalystparticledecreasedandtheavailablecrystalforO2reductionincreased;2)theMPt/CcatalystshadrelativelyhighBETsurfaceareas;and3)thesecrystaltransformationsoftheMPt/Ccatalystbroughthightheelectrocatalyticactivity,andasaresult,improvedthepowerofPEMFC.
简介:ThepartialoxidationofethanoltohydrogenwasinvestigatedoverNi/Fe/Lacatalystspreparedbytheco-precipitationmethod.TheeffectsofintroductionofLapromoterandthereactiontemperatureonthecatalyticperformancewerestudied.ItwasfoundthattheintroductionofLaintoNi/Fecatalystsishelpfultoincreasetheselectivitytohydrogenandthestabilityofthecatalysts.TheresultsofXRDandXPScharacterizationshowthatthestructureofthecatalystwaschangedduringthereaction.TheexistenceofLaFeO3speciesispossiblythemainreasonoftheincreaseofthecatalyststability.
简介:Thebilayerorganiclight-emittingdiode(OLED)withabluefluorescentlanthanumcomplex,tris(1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone)-(2,2′-dipyridyl)lanthanum[La(PMIP)3(Bipy)],asalightemittingmaterialandN,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine(TPD)asaholetransportingmaterialemitsbrightgreenlightinsteadofbluelight.Thedataoftheabsorption,thephotoluminescence(PL)andthephotoluminescenceexcitation(PLE)spectraofTPD,La(PMIP)3(Bipy)andthemixtureofTPDandLa(PMIP)3(Bipy)(molarratio1∶1)provethattheelectroluminescentemissionoriginatesfromtheexciplexontheinterfacebetweenTPDandLa(PMIP)3(Bipy).Byimprovingdeviceconfigurationwithtris(8-hydroxyquinoline)aluminum(ALQ)asanelectrontransportingmaterial,amaximumluminanceof800cd/m2wasobtained.
简介:ThetemperaturedependenceofresistivityρofYSZdopingcompositeof(1-x)La0.67Ca0.33MnO3+xYSZandY2O3dopingcompositeof(1-y)La0.67MnO3+yY2O3isinvestigated,respectively,inatemperaturerange77-300K,wheretheYSZrepresentsyttria-stabilizedzirconia(8mol%Y2O3+92mol%ZrO2).ExperimentalresultsshowthattheYSZdopinglevelhasimportanteffectsonboththemetal-insulator(M-I)transitiontemperaturesandzerofieldresistivityofthecompositesof(1-x)La0.67Ca0.33MnO3+xYSZ.However,theY2O3dopinglevelhaslittleeffectontheM-Itransitiontemperaturesandthezerofieldresistivityof(1-y)La0.67Ca0.33MnO3+yY2O3onlyincreasesslightly.Thedifferencebetweenthetwotypesofcompositesmaymainlyresultsfromthedifferentdistributionofhighresistancephasesatthegrainboundariesand/orsurfacesofLa0.67Ca0.33MnO3grainsratherthanthesubstitutionofLa^3+ionswithY^3+ions.
简介:Thetitlecomplex,[La(baec)1/2(H2btec)1/2(H2O)]n(H4btec=1,2,4,5-benzenetetracarboxylicacid)(1)wassynthesizedbythehydrothermalreactionof1,2,4,5-benzenetetracarboxylicdianhydridewithLa(NO3)3·6H2OinH2O,andcrystallizesinthetriclinicsystem,spacegroupP-1withα=0.64403(3)nm,b=0.94500(4)nm,c=0.96380(5)nm,α=88.535(2)°,β=100.314(2)°,γ=76.6470(10)°,V=1.69968(10)nm^3,Z=2,andfinalR=0.0274,Rw=0.0735.In1,eachLa(Ⅲ)ioniscoordinatedbyeightoxygenatomsfromsixcarboxylategroupsandonecoordinatedwatermolecule.TwodifferentcoordinstionmodesofH4btecwerePresentinthestructure,oneofwhichcontainstwoprotonatedcarboxylategrougpstobalancethecharge.