氢气在Na-MAZ和Li-MAZ沸石原子簇上的吸附.pdf

《氢气在Na-MAZ和Li-MAZ沸石原子簇上的吸附.pdf》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、物理化学学~(WuliHuaxueXuebao1JulyActaPhys．一C。，z．2011，27(7)，1647—16531647[ArticleJwww．whxb．pku．edu．CII氢气在Na—MAZ和Li．MAZ沸石原子簇上的吸附梁建明’章日光赵强’董晋湘’王宝俊李晋平(太原理工大学精细化工研究所，太原030024；太原理工大学煤科学与技术教育部和山西省重点实验室太原030024)摘要：采用基于密度泛函理论(DFT)的广义梯度近似(GGA)／PBE(Perdew-Burke．Emzerh0f)交换相

2、关泛函和双数值基加P极化(DNP)基组对氢气分子在Na．MAZ和Li．MAZ沸石原予簇上的吸附进行了研究，计算得到吸附复合物的平衡几何结构参数、振动频率以及吸附能等数据．结果表明：MAZ沸石中存在四个稳定的吸附位点，分别为SI、SS和S位点：氢气分子在Na—MAZ沸石的SII”位点吸附时最稳定，而在Li．MAZ沸石中．氢气分子处于SI，，和S位点时最稳定．吸附能越大，氢气分子键长越长，振动频率减少也越多．Li．MAZ沸石对氢气的吸附能力要明显强于Na—MAZ沸石的吸附能力，理论上Li．MAZ沸石具有更高的氢气储

3、量，可能是～一种潜在的储氢材料关键词：MAZ沸石：氧气；吸附；密度泛函理论：广义梯度近似中图分类号：O641HydrogenAdsorptiononZeoliteNa—MAZandLi·MAZClustersLIANGJian—Ming’ZHANGRi—GuangZHAOQiang’DONGJin—Xiang’WANGBao—Jun，LIJin—Pingr(ResearchInstituteofSpecialChemicals，TaiyuanUniversityofTechnology,Taiyuan03002

4、4．R．China；KeyLaboratory03CoalScienceandTechnology,MinistryofEducationandShanxiProvinceTa~uanUniversityofTechnology,Zaiyuan030024,R，China)Abstract：HydrogenadsorptiononzeoliteNa·-MAZandLi．MAZclusterswasinvestigatedusingdensityfunctionaltheory(DFT)withthegenera

5、lizedgradientapproximation(GGA)ofthePerdew．Burke．Ernzerhof(PBE)exchange—correctionfunctionalandthedoublenumericalpluspolarization(DNP)basisset．EquilibriumstructuraIparameters，vibrationfrequencies，andadsorptionenergieswereobtainedandcompared．Thecalculatedresu

6、ltsshowthatfourstableadsorptionsitesarepresenlonzeoliteMAZ．TheyaredesignatedSl，Sl”，Sll，andSll”，respectively．ThemoststableadsorptionstructurewashydrogenontheSII”siteofzeoliteNa—MAZandthehydrogenontheSl”andSll”sitesofzeoliteLi—MAZwerethemoststable．Wealsofoundf

7、hatlargeradsorptionerergiesindicatelongerH—HbonddistancesandaIowervibrationfrequencyshift．TheadsorptionabilityofzeoliteLi-MAZtowardhydrogeniSstrongerthanthatofzeoliteNa—MAzZeoliteLi-MAZhasahighertheoreticaIhydrogenstoragecapacityanditmaybeapotentiafhydrogens

8、toragemateriaIKeyWords：ZeoliteMAZ；Hydrogen；Adsorption；Densityfunctionaltheory；GeneralizedgradientapproximationReceived：January20，2011；Revised：May9，2011；PublishedonWeb：May23，2011．Correspondingaut