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催化学报 2008
CeO2掺杂的Mn/Al催化剂的物化、表面及催化性能, PP. 687-695 Keywords: catalyticactivity,manganeseoxide,activationenergy,alumina Abstract: ？PureandCeO2-dopedMn/Almixedoxideswerepreparedbythewetimpregnationmethodusingfinelypowderedalumina,manganese,andceriumnitrates.Thephysicochemical,surface,andcatalyticpropertiesofthethermallytreatedsolids(at500,800,and900℃)wereinvestigatedusingXRD,nitrogenadsorptionat-196℃,andhydrogenperoxidedecompositioninanaqueoussolutionat30~50℃.TheMnoxidationstatechangedfromMn4+toMn2+onincreasingthecalcinationtemperature.ThereweretwouniquefeaturesassociatedwithCeO2thatareofinterest.Thefirstwasthatitfavoredthedispersionofmanganeseoxidesdepositedontheγ-Al2O3catalystcalcinedat500℃.ThesecondwasthatitenhancedtheformationofMn3O4speciesfromMn2O3depositedinitiallyonthealuminasupportcalcinedat800and900℃.Consequently,thespecificsurfaceareaoftheMn/Almixedoxidescalcinedat500℃wasincreasedbyincreasingtheamountofdopantadded.Anoppositeeffectwasobservedbyincreasingthecalcinationtemperaturefrom500to900℃.Thedopingfollowedbycalcinationatdifferenttemperaturesbroughtaboutanincreaseinthecatalyticactivityofmixedoxides.Pretreatmentsdidnotmodifythemechanismofthecatalyzedreactionbutchangedthenumberofcatalyticallyactivesiteswithoutchangingthenatureofthesesites.
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