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1、物理化學(xué)學(xué)~(WuliHuaxueXuebao)OctoberActaPs.一Chim.Sin.2013,290o),2207-22142207[Article]doi:l0.3866/PKU.WHXB201307191www.whxb.pku.edu.cn多孔金屬有機(jī)骨架材料儲氫性能分子模擬吳選軍鄭佶李江蔡衛(wèi)權(quán)(武漢理工大學(xué)化學(xué)工程學(xué)院,武漢430070)摘要:采用優(yōu)化的DREIDING力場參數(shù),通過巨正則系綜蒙特卡洛(GCMC)模擬方法對H:在IRMOF一1、IRMOF.61和lRMOF.62共3種金屬有機(jī)骨架(MOFs)材料中的吸附平衡性能進(jìn)行了比較研究.結(jié)果表明,該力場能夠在全壓力
2、范圍內(nèi)很好地復(fù)制H在IRMOF.62材料中的等溫吸附曲線:但對低壓下H在lRMOF.61中的等溫吸附曲線預(yù)測出現(xiàn)低估.與IRMOF-1相比,具有互穿骨架結(jié)構(gòu)的lRMOF一61和IRMOF-62材料在常溫下的儲氫能力并無明顯提高.進(jìn)一步比較77K時100kPa、3.0MPa下H在上述MOFs材料中達(dá)到吸附平衡時的幾率密度分布發(fā)現(xiàn),H:會優(yōu)先吸附在ZnO骨架附近靠近苯環(huán)的位置:對具有互穿結(jié)構(gòu)的MOFs材料而言,由于其孔腔尺寸縮小,使得H優(yōu)先吸附位區(qū)域零散化.適當(dāng)長度的有機(jī)配體形成的互穿骨架結(jié)構(gòu)能增強(qiáng)與H分子之間的相互作用,具備較高的儲氫能力:而有機(jī)配體尺寸過長則會增加骨架結(jié)構(gòu)中H2吸附死角,對
3、H。的吸附能力反而出現(xiàn)下降.關(guān)鍵詞:金屬有機(jī)骨架材料:多孔材料:巨正則系綜蒙特卡洛模擬:儲氫:等溫吸附中圖分類號:O641MolecularSimulationonHydrogenStorageCapacitiesofPorousMetalOrganicFrameworkswuXuan-JunZHENGJiLIJiangCAIWei—Quan(SchoolofChemicalEngineering,WuhanUniversityofTechnology,Wuhan430070,PR.China)Abstract:TheadsorptionequilibriumpropertiesofH2m
4、oleculeslnvariousmeta1.organicframeworks(MOFs)includinglRMOF.61,IRMOF-62,andIRMOF.1werestudiedusingthegrandcanonicaIMonteCarlo(GCMC)simulationmethodwiththeoptimizedparametersobtainedusingtheDRElDINGforcefield.ThecalculafedparameterscouldexactlyreproducetheadsorptionisothermsofH2moleculesinlRMOF.62
5、.However,theymayunderestimatetheadsorptionisotherm0fH2moleculesinlRMOF.61atlowpressure.TheH2storagecapacities0fIRMOF一61andlRMOF一62withinterpenetratingframeworkswerenotsignificantlyhigherthanthatoflRMOF.1atroomtemperature.H2moleculeswerepreferentialyadsorbednearZn40units.whichwereIocatedclosetotheb
6、enzenerings,accordingtotheprobabilitydensitydistributionofH2moleculesintheaboveMOFsunderadsorptionequilibriumconditionsat77K,100kPa,and3.0MPa.FortheMOFswithinte~enetmtingframeworks,theareawithpreferentiaIadsorptionsitesforH2moleculesissmallerandmorescatteredthantheMOFwithoutbecauseoftheirsmallerca
7、vitysizes.TheorganicIinkershouldbeofappropriateIengthtopromotetheformationofaninterpenetratingframework,whichcanenhancetheinteractionbetweentheframeworkandH2molecules,andthusimproveH2storagecapacity.Iftheorganicl