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1、物理化學(xué)學(xué)報(bào)(WuliHuaxueXuebao)2872ActaP@s.一C..2011,27(12),2872-2880December[Article]doi:10.3866/PKU.WHXB20112872Ⅵ~rw.whxb.pku.edu.cna.MnO2負(fù)載納米Au催化劑低溫催化氧化CO和苯的性能葉青霍飛飛閏立娜王娟程水源康天放(北京工業(yè)大學(xué)環(huán)境與能源工程學(xué)院,北京100124)摘要:以尿素為沉淀劑用沉積.沉淀法制備了MnO負(fù)載Au催化劑xAu/mMnO(x=0—7(對(duì)應(yīng)的Au負(fù)載量(質(zhì)量分?jǐn)?shù))分別為O一7%)),使用X射線粉
2、末衍射(XRD)、N-吸附/脫附、透射電鏡(TEM)、X射線光電子能譜(XPS)和H.程序升溫還原(H.TPR)等技術(shù)對(duì)所制樣品進(jìn)行了表征,并測(cè)定其對(duì)CO和苯的催化氧化性能.XRD結(jié)果表明,負(fù)載Au對(duì)a-MnO載體結(jié)構(gòu)影響不大,隨Au含量的增加,Au顆粒明顯增大.N一吸附,脫附和TEM結(jié)果表明,Au的加入對(duì)xAu/a-MnO的比表面積、孔容和孔徑等結(jié)構(gòu)性能影響較小,表明Au分布在mMnO載體表面,未阻塞其孔道.XPS結(jié)果表明,隨著Au負(fù)載量的增加,xAu/a-MnO中的O一,(Ol一或O一)、Mn/Mn。和Au”,Au。的摩爾比在增加,
3、表明其晶格氧、Mn和Au。的濃度在增加.由于貴金屬的溢氫作用,Au明顯促進(jìn)xAula-MnO:氧化還原能力,其中3Au/mMnO具有最高的氧化還原性.負(fù)載Au明顯影響xAu/a-MnO樣品的催化活性,xAu/a-MnO:的催化性能與Au的分散性、氧化還原性能及表面氧物種的種類密切相關(guān),其中3Au/mMnO顯示出最佳活性,其催化氧化CO的。=80。C,苯的。=200。C.關(guān)鍵詞:a-MnO負(fù)載Au催化劑:低溫還原性:相互作用:CO氧化:苯催化燃燒中圖分類號(hào):0643HighlyActiveAu/a·Mn02CatalystsfortheL
4、ow-TemperatureOxidationofCarbonMonoxideandBenzeneYEQingHUOFei—FeiYANLi-NaWANGJuanCHENGShui—YuanKANGTian—Fang(CollegeofEnvironmentalandEnergyEngineering,BeringUniversityofTechnology,Beo'ing100124PPChina)Abstract:a-MnO2一supportedgoldcatalysts(xAu/a-MnO2,x=0-7(corresponding
5、totheAuloading(massfraction)of0-7%)werepreparedbyadeposition—precipitationmethodusingureaasaprecipitationagentandcharacterizedbydifferenttechniquessuchasX-raydifractionfXRD),N2adsorption—desorptionmeasurements,transmissionelectronmicroscopy(TEM),X—rayphotoelectronspectro
6、scopy(XPS),andH2temperature.programmedreduction(TPR).ThecatalyticactivitiesofthematerialswereevaluatedfortheoxidationofCOandbenzene.TheAuparticlesizewasfoundtoberelatedtotheAuIoadingofthexAu/cr_Mn02samplesandincreasedwithAuIoading.XPSresultsshowedthatthemoleratiosofO2。/(
7、02一or0’),Mn,Mn”andAu。/Au。increasedupontheadditionofAu.Theloadingofgoldovera-Mn02significantlymodifiedthecatalyticactivities.ThecatalyticperformanceofxAu/cr-MnO2stronglydependedontheAuloading,and3Au/a-Mn02gainedthebestactivityato=80。Cand丁g0=20。CforthecatalyticoxidationofC
8、Oandbenzene.respectively.Theexcellentperformanceof3Aula-Mn02isassociatedwithhighlydispersedAu,goodIow.t