MoO_3改性的TiO_2在可见光下催化降解亚甲基蓝

作者:杨华博;李翔;王安杰;王瑶;陈永英 刊名:催化学报 上传者:梁霞

【摘要】采用浸渍法制备了MoO3/P25催化剂(MoO3/P25(x),x为MoO3与P25质量比),用X射线衍射、紫外-可见漫反射光谱、傅里叶变换红外光谱及拉曼光谱等手段对样品进行了表征,并用催化降解亚甲基蓝考察了催化剂在可见光区的催化活性.结果表明,MoO3在P25表面最大单层负载量对应的MoO3与P25质量比在0.1左右.单层分散的氧化钼物种与P25之间有较强的相互作用,降低了P25禁带宽度,提高了催化剂对可见光的吸收.当MoO3与P25质量比大于0.1时,会生成晶相MoO3,催化剂对可见光的吸收反而随MoO3担载量增加而降低.催化剂禁带宽度不是决定其可见光下催化降解亚甲基蓝活性的唯一因素.具有适宜禁带宽度和一定晶相MoO3含量的MoO3/P25(0.25)表现出最佳活性.

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1.IntroductionTiO2isthemostfrequentlyusedphotocatalystduetoitslowcost,highstability,andhighphotocatalyticoxidationactivity.InthepresenceofTiO2,mostorganicpollutantscanbephotocatalyticallydegradedandmineralizedtoCO2,H2O,andothersmallinorganicmolecules.However,TiO2hasarelativelylargebandgap(3.03.2eV),requiringhighenergyultraviolet(UV)lightforactivation,andalsosuffersfromlowquantumyield.Hence,mostoftheeffortstowardsmodifyingTiO2toenhanceitsvisiblelightabsorptionandsolarenergyconversionefficiencyhavebeendevotedtoreducingitsbandgapandimprovingitsquantumefficiency.Thereportedmethodsincludemetaldeposition[1,2],iondoping[3],couplingwithothersemiconductors[4],andorganicphotosensitization[5].ThebandgapofMoO3is2.9eV,whichisclosetothatofTiO2,andstronginteractionsoccurbetweenMoO3andTiO2[6].ManystudieshaveindicatedthatthephotocatalyticactivityofTiO2intheUVregionorthevisiblelightregioncanbeimprovedbyMoO3doping.Forexample,Kubackaetal.[7]studiedmixedTiM(M=V,Mo,Nb,andW)oxidesandreportedthatonlystructurallyhighlyhomogeneousanatasetypeoxideswithelectronicpropertiesexclusivelyproducingadecreaseinbandgapmayleadtoefficientvisiblelightdrivenphotocatalysts. 妕englandBakardjieva[8]foundthatadditionofMoO3ledtoanincreaseintheactivityofanataseforthedegradationofOrangeIIdyeintheUVandvisibleregions.Inthepresentwork,MoO3wasintroducedtoP25(TiO2,ratioofanatasetorutileof80:20)byanincipientwetnessimpregnationmethod,andtheinfluenceofMoO3dispersiononthephotocatalyticperformanceofP25undervisiblelightwasstudiedusing

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