La掺杂TiO2光催化剂的制备与表征赵清华

:0253-9837(2008)03-0269-06:269～274:2007-09-10.　:,,1974,.:.Tel/Fax:[phone];E-mail:[e-mail].:(2005CC41).LaTiO2赵清华,　全学军,　谭怀琴,　桑雪梅(重庆工学院化学与生物工程学院化学工程系,重庆400050):-LaTiO2(La3+-TiO2),B,.,La3+-TiO2,La1.0%、800℃2h.X、N2、.TiO2,、/,.:;;;;-:O643　　　:APreparationandCharacterizationofLa-DopedTiO2PhotocatalystsZHAOQinghua,QUANXuejun＊,TANHuaiqin,SANGXuemei(DepartmentofChemicalEngineering,SchoolofchemicalandBiologicalEngineering,ChongqingInstituteofTechnology,Chongqing400050,China)Abstract:Lanthanum-dopedTiO2,photocatalystsLa3+-TiO2,werepreparedbycoprecipitationandsol-gelmethods.RhodamineBwasusedasthereactanttoevaluatethephotocatalyticactivityofthecatalystsamples.TheresultsshowedthattheLa3+-TiO2catalystpreparedbycoprecipitationexhibitedobviouslyhigherphoto-catalyticactivity.Theoptimumpreparationconditionsofcoprecipitationwerelanthanumionsdopedof1%,cal-cinationtemperatureof800℃,andcalcinationtimeof2h.ThebestcatalystsampleswerecharacterizedbyX-raydiffraction,N2adsorption-desorptionmeasurement,scanningelectronmicroscopy,andelectronprobemi-croanalyses.Thetwophotocatalystspreparedbycoprecipitationandsol-gelbothhadmixedcrystalstructureofanataseandrutile,andtheanatasecontentswere80%and70%,respectively.Thehigherphotocatalyticactivi-tyoftheLa3+-TiO2catalystpreparedbycoprecipitationwasmainlyattributedtoitsmoreregularstructureofanatase,largercrystalsize,andhierarchicalmacro/mesoporousstructure.Keywords:photocatalyst;lanthanumdoping;titaniumdioxide;coprecipitation;sol-gelmethod　　TiO2,[1～4].TiO2,.,3%～4%.TiO2,,,TiO2,[5～8].,La,f(、、、)Lewis,,TiO2[9～15].　　,-293　　　20083Vol.29No.3ChineseJournalofCatalysisMarch2008[10～12],,.TiCl4La(NO3)3,LaTiO2(La3+-TiO2),TiO2.1　1.1　　　-La3+-TiO2,.　　La3+-TiO2[16],1mol/LTiCl4,La(NO3)3·6H2O,.7mol/L,TiO(OH)2La(OH)3,pH9.33,.,La3+(c(La3+)10μmol/L).30min,,、,,0.5mol/LNH+4Cl-,70℃,.2h,,,La3+-TiO2.　　-La3+-TiO2[12],、、、La3+-TiO2.1.2　　　,300ml[17],B.50W,,10cm.200ml,10mg/L,0.40g,0.8L/min.1h,UV-2000-λ=553nmB.　　,10mlB,0.1gLa3+-TiO2,,25℃150r/min24h,,,B,.　　,,.1.3　　　D/MAX-3CX,:CuKα,20kV,20mA,2°/min.BechmanCoulterSA3100PlusBET,120℃20min,0.0527～0.18BET.BJH,,.JEOLJSM-6460LV.JEOLJXA-8800.Rise-2008.2　2.1　　　B1.TiO2La3+(La/TiO20～2.0%).-,La3+-TiO2,.　　.La3+-TiO2,.,TiO2,.,.,700～800℃,-600℃..[18]-La3+-TiO2,600℃,.,Ranjit[10,11]-La3+-TiO2550℃,.　　La.270　　　291　La3+-TiO2BFig1　PhotocatalyticdegradationefficiencyofrhodamineBoverLa3+-TiO2catalystspreparedbycoprecipitation(a)andsol-gelmethods(b)aftercalcinationatdif-ferenttemperaturefor2h(SStandarddeviation,La3+-TiO2Lanthanum-dopedTiO2.)Xu[12]Li[14]-La0.5%1.2%.La.-600℃2hLa0.5%～1.0%,.,700～800℃2hLa3+-TiO2,La0.5%～1.0%,-.　　,,,.2.2　　　800℃La1.0%COP1.0%La-TiO2-800,-600℃La1.0%SG1.0%La-TiO2-600.,Langmuir[14]C/Г=C/Гmax+1/(KaГmax)(CB,mg/L),C/ГCГmaxKa,1.,BLang-muir,R20.9500.-,,.L-HR=kKC/(1+KC)[12](R,k,K),-.,k,k.1　La3+-TiO2BTable1　AdsorptionparametersofcatalystsamplesinrhodamineBsolutionSampleГmax/(mg/g)Ka/(L/mg)R2COP1.0%La-TiO2-8000.10910.17420.9807SG1.0%La-TiO2-6000.16580.17740.9560COP1.0%La-TiO2-800Catalystpreparedbycoprecipita-tionat800℃with1%La;SG1.0%La-TiO2-600Catalystpreparedbysol-gelat600℃with1%La;ГmaxSaturatedadsorptioncapacity;KaAdsorptionequilibriumconstant;R2Relativecoefficient.2.3　XRD　　2-XRD.,COP1.0%La-TiO2-800SG1.0%La-TiO2-600,.,[19,20].ScherrerD=0.89λ/βcosθ[12],-22.9617.22nm.SG1.0%La-TiO2-600Li[14]1.2%La-TiO2(17.66nm).,XA=[1+1.26(IR/IA)]-1[21],XA,IR/IAX2713:LaTiO22　XRDFig2　XRDpatternsoftwodifferentLa3+-TiO2photocatalysts(1)COP1.0%La-TiO2-800,(2)SG1.0%La-TiO2-600..,COP1.0%La-TiO2-800SG1.0%La-TiO2-60080%70%.2　La3+-TiO2Table2　PorestructurepropertiesoftwoLa3+-TiO2samplesSampleBETsurfacearea(m2/g)Porevolume(cm3/g)Poresize＊(nm)Average10%25%50%75%90%COP1.0%La-TiO2-80014.90.12132.5≤18.9≤28.2≤36.9≤44.6≤57.6SG1.0%La-TiO2-60036.70.0758.2≤4.5≤5.7≤7.7≤10.4≤24.9＊Numbers10%,25%,50%,75%,and90%refertoporesizedistribution,i.e.,thevolumepercentageoftheporeswithdiametersmallerthanthecorrespondingporesize.　　2,,COP1.0%La-TiO2-800800℃,,SG1.0%La-TiO2-600200℃,(2θ=27.6°,36.4°54.45°).600～1100℃[11],-LaTiO2[10,14].,La,La,La3+-TiO2.　　LaTiO2,La3+-TiO2,TiO2Ti-O-LaLa2O3,,[11,12,14].Overstone[22],,La.Ti(OH)4La(OH)3,-(C4H9O)4TiLa(NO3)3.,,TiO2Ti-O-LaLa2O3,,.,,[20].　　,TiO2,[15].COP1.0%La-TiO2-800,SG1.0%La-TiO2-600,[19,20],La3+-TiO2.,[10,11],,.2.4　BET　　,BET,2.,COP1.0%La-TiO2-800SG1.0%La-TiO2-600,4,SG1.0%La-TiO2-600(2～50nm),COP1.0%La-TiO2-80075%25%(50nm),.TiO2[23,24],,,.[25]./,,272　　　29,[19,20].　　SG1.0%La-TiO2-600(36.7m2/g)COP1.0%La-TiO2-800(14.9m2/g),,(1).,,,Ran-jit[11][26].4　SEMFig4　SEMimagesofthecatalystsamples(a)COP1.0%La-TiO2-800,(b)SG1.0%La-TiO2-6002.5　SEM　　1min,3.,,,COP1.0%La-TiO2-800SG1.0%La-TiO2-60018.817.3μm,.3　1minFig3　Particlesizedistributionofthesamplepowdersinwaterafterultrasonicdispersionfor1min　　SEM,4.(2～20μm),.COP1.0%La-TiO2-800,.,SG1.0%La-TiO2-600,..2.6　　　(),TiO,O/Ti2.49,.Li[14]-1.2%La3+-TiO2,O/Ti2.70,O/TiLa,OLa2O3.Li[14].　　-La3+-TiO2O/Ti,.Li[14]-La3+-TiO2Ti,O,CLa,C,Ti,OLa.[14],TiLa2O3CTi4+,La3+-TiO2Ti3+.,C,La3+-TiO2Ti3+-.　　La3+-TiO2La2O3TiO2,-,La2O3((SHE)-1.8～-3.5eV)TiO2(SHE-0.3eV),TiO2La2O3[9,14].,,La3+