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《Ti, V, Nb 摻雜MgH 2 儲氫體系的放氫性能及微觀機(jī)理Dehydrogenation》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在行業(yè)資料-天天文庫。
1、2010年第68卷化學(xué)學(xué)報(bào)Vol.68,2010第20期,2077～2085ACTACHIMICASINICANo.20,2077～2085·研究論文·Ti,V,Nb摻雜MgH2儲氫體系的放氫性能及微觀機(jī)理,abaa張健*黃雅妮毛聰龍春光aab邵毅敏付俊慶彭平a(長沙理工大學(xué)汽車與機(jī)械工程學(xué)院長沙410114)b(湖南大學(xué)材料科學(xué)與工程學(xué)院長沙410082)摘要采用基于密度泛函理論的贗勢平面波方法,計(jì)算了過渡金屬元素Ti,V,Nb摻雜MgH2儲氫體系的幾何構(gòu)型、能量與電子結(jié)構(gòu).結(jié)果顯示:Ti,V,
2、Nb摻雜原子較Mg表現(xiàn)出更強(qiáng)的“親氫性”,摻雜原子在吸引周圍H原子同時(shí)卻削弱了體系中的H—Mg鍵強(qiáng);摻雜體系相結(jié)構(gòu)穩(wěn)定性降低,放氫性能提高,且體系放氫能力按MgH2-Ti,MgH2-V,MgH2-Nb順序依次增強(qiáng);放氫過程中,摻雜原子與周圍H原子所形成的氫化物團(tuán)簇對改善體系放氫性能表現(xiàn)出主要的催化活性;摻雜元素改善MgH2體系放氫性能的微觀機(jī)理在于摻雜體系在費(fèi)米能級附近能隙的變窄、低能級區(qū)成鍵電子數(shù)的減少以及H—Mg間相互作用的減弱.關(guān)鍵詞MgH2;贗勢平面波;放氫性能;電子結(jié)構(gòu)Dehydroge
3、nationPropertiesandMicromechanismsofMgH2HydrogenStorageSystemswithTi,VorNbDoping,abaaZhang,Jian*Huang,YaniMao,CongLong,ChunguangaabShao,YiminFu,JunqingPeng,Pinga(InstituteofAutomobileandMechanicalEngineering,ChangshaUniversityofScienceandTechnology,Ch
4、angsha410114)b(CollegeofMaterialsScienceandEngineering,HunanUniversity,Changsha410082)AbstractUsingthepseudopotentialplane-wavemethodbasedondensityfunctionaltheory,thegeometricalconfiguration,energeticsandelectronicstructuresofMgH2hydrogenstoragesyste
5、mswithtransitionmetalsTi,VorNbdopinghavebeencalculated.ThedopingatomofTi,VorNbexhibitsmorenotableaffinitywithhydrogenascomparedwithMgatom.ThebondingstrengthofMg—Hisweakenedwhenthedopingatompullsnearbyhydrogenatomstowarditself.DuetothedopingofTi,VorNb,
6、thestructuralstabilitiesofMgH2systemsaredecreasedandtheirdehydrogenationpropertiesareimproved,aswellas,thedehydrogenationabilitiesofdopedsystemsareincreasedgraduallyinorderofMgH2-Ti,MgH2-VandMgH2-Nbsystems.Theclustersofhydridesformedfromdopingatomsand
7、hydrogenplaysignificantcatalyticroleinimprovingthedehydrogenationpropertiesofMgH2systems.ThemicromechanismsofimprovedpropertieslieinthenarrowingoftheenergygapnearFermienergylevel,thedecreasingofbondingelectronsnumberaswellastheweakeningofH—Mginteracti
8、onsindopedsystems.KeywordsMgH2;pseudopotentialplane-wave;dehydrogenationproperty;electronicstructure為解決能源短缺、環(huán)境污染日益嚴(yán)重和經(jīng)濟(jì)可持續(xù)發(fā)展等問題,開發(fā)清潔可再生能源已迫在眉睫.氫能以*E-mail:zj4343@163.comReceivedMay2,2010;revisedJune18,2010;acceptedJuly13,2010.長沙理工大學(xué)人才引進(jìn)基金(No.20
