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1、StudiesinSurfaceScienceandCatalysis146Parketal(Editors)©2003ElsevierScienceB.V.Allrightsreserved129AfurtherinvestigationoneffectofbasicmediaonthesynthesisofMCM-41ChunYang^'^ShuxunGe^andNongyueHe"''^KeyLaboratoryofNewMaterialsandTechnologyofChinaNationalPackagingCorporation,ZhuzhouEngineering
2、College,Zhuzhou412008,P.R.China^CollegeofChemistryandEnvironmentalScience,NanjingNormalUniversity,Nanjing210097,PR.China^KeyLaboratoryforMolecularandBio-molecularElectronicsofMinistryofEducation,SoutheastUniversity,Nanjing210096,P.R.ChinaPuresiliceousMCM-41samplesweresynthesizedinstrongandwe
3、akalkalinemedia(sodiumhydroxideandethylenediamine).DifferentpHrangesforsynthesiswereobtainedfordifferentalkalinemedia.Ethylenediaminegavethesampleshigherstructuralorderandstability,andallowedtheuseofabroaderpHrangethatmakesiteasiertosynthesizeMCM-41ofgoodquality.Theadvantageofethylenediamine
4、mayresultsfromtheincreaseofchargedensityonthesurfaceofsurfactantmicellesowingtothepenetrationofconjugatedacidcationoftheorganicbase.1.INTRODUCTIONHexagonalMCM-41-typemesoporousmaterialsshowingalong-rangeorderarepotentiallyusefulinsomeapplicationsrequiringregularnano-metricporousstructureowin
5、gtotheiradjustableporesizeandhexagonallypatternedone-dimensionalchannelstructure[1].Therefore,manystudieshavebeenfocusedonthesynthesisofMCM-41withregularmesostructure[2-4].ThesematerialsusuallyarehydrothermallysynthesizedinanalkalinemediumthroughS^I"mechanism,andstrongbases,suchasNaOHand(CH3
6、)4NOH,areusuallyemployedasalkalinemediaforthesynthesis.However,thermalstabilityofthesamplespreparedfromstrongalkalinemediaissopoorthattheregularityinstructurecan'tbemaintainedduringthecalcinations[3,5].Inrecentreports,weakbases(NH3,methylamine,ethylamine,dimethylamineanddiethylamine)wereused
7、inthesynthesisofMCM-41[6-8].Itwasfoundthattheweakbasescouldendowthesampleswithhighstructuralorderandhydrothermalstability[8].Therefore,itisimportanttoinvestigatethemechanismofeffectofalkalinemediainthesynthesis.HerewecomparethesynthesisofMCM-41inwe