铜锌镁铝四元水滑石的微观结构及其姜-泰勒畸变.pdf

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1、物理化学学~(WuliHuaxueXuebao158Acta．-Chim．．2012，28(1)，58—64January[Article]doi：l0．3866／PKU．WHXB20122858www．whxb．pku．edu．cn铜锌镁铝四元水滑石的微观结构及其姜．泰勒畸变王力耕施炜姚萍倪哲明李远刘娇(浙江工业大学化学工程与材料学院，先进催化材料实验室，杭州310032)摘要：采用密度泛函理论(DFT)，选取CASTEP程序模块，对铜锌镁铝四元水滑石【(M)．IV-LDHs(M=Cu，Zn，

2、Mg，A1)】周期性模型进行几何全优化，从各体系的结构参数、电子排布、Mulliken电荷布居、结合能、氢键等方面，研究了体系中的姜．泰勒效应、氯离子位置对层板畸变及体系稳定性的影响．优化结果表明，姜．泰勒效应不仅存在于d轨道未排满的Cu中，也存在于理论上d轨道排满的Zn与P轨道未排满的Mg中．氯离子排在金属上方的体系，其金属畸变程度大于氯离子排在非金属上方的体系．同时，对于本文选取的8个CuAI．IV-LDHs体系，结合能绝对值按照1—8号逐渐降低，体系的稳定性下降，最终转变为不稳定的压扁的八

3、面体构型．这有助于从理论上对含铜四元水滑石的姜一泰勒效应进一步认识．关键词：四元含铜水滑石：密度泛函理论：姜．泰勒效应中图分类号：O641MiCroStruCtureandJahn—TellerEfectofCu-Zn—Mg-AILayeredDoubleHydroxidesWANGLi-GengSHIWeiYAOPingNIZhe—MingLIYuanLIUJiao(LaboratoryofAdvancedCatalyticMaterials，CollegeofChemicalEngineer

4、ingandMaterialsScience，ZhejiangUniversityofTechnology,Hangzhou310032，PR．China)Abstract：Weproposeaperiodicinteractionmodelforlayereddoublehydroxides，CuZnMgAIquaternaryhydrotalcites【(M)一IV-LDHs(M=Cu，Zn，Mg，A1)】．Basedondensityfunctionaltheorythegeometrie

5、sofCuZnMgAIquaternaryhydrotalciteswereoptimizedusingtheCASTEPprogram．TheimpactsoftheJahn．TeIlerefectandtheIocationofchlorineoverthelayerdistortionandstabilitywereinvestigatedbyanalyzingthegeometricparameters，theelectronicarrangement，chargepopulations

6、，bindingenergles，andhydrogen．bonding．TheoptimizationresultsshowedthattheJahn-TeIlerefectdoesnotonlyexistinCuwhenitsdorbitaIiSpartiallyfilledbutitalsoexistsinZnwhenitsdorbitaIiSfulIaswelIasinMgwhenitsPorbitaIiSpartiallyfilled．SystemswherethechlorideiS

7、locatedabovethemetalshowgreatermetaJdistortionthansystemswithanionsJocatedabovenon—metals．Eightsystems(Nos．1—8)werechosenforourworkandtheirabsolutebindingenergyvalueswerefclundtodecreasegraduallywhilethestabilityofthesystemsbecameworse．Finally，thesys

8、temsbecameunstableandwerefoundtobeflattenedoctahedralforms．TheseresultshelpUStobetterunderstandtheJahn-TellerefectincOpDe卜c0ntainingl、，_LDHSfromtheory．KeyWords：COpper_cOntainingquaternaryhydrotalcite；Densityfunctionaltheory；Jahn。Tellerefect1引言M表示二价金属