AB储氢开题.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Basic Research For The Hydrogen Fuel Initiative,-,An Introduction For A,High Capacity Hydrogen Storage Material,:,Ammonia,Borane,(AB),Reporter:*,Reference,Hydrogen storage materials developments,1,Background on ammonia,borane,2,Recent studies of ammonia,borane,3,Further work,4,5,1.Hydrogen Storage Materials Developments,Hydrogen storage,materials,Global population growth,Cadidate,hydrogen storage materials,1.Metal hydrides,2.Complex hydrides,3.Sorbent systems,4.Chemical hydrides,Industry rapid pace,Overview of the properties of the major hydrogen storage materials classes,Fig.1 Reprinted from Ref.1,Summary of thermodynamic and theoretical capacity data for hydrogen storage reactions of recent interest,Table.1 Reprinted from Ref.1,Limitation of conventional hydrogen storage materials,1.Metal hydrides:The gravimetric density is too low or the thermodynamics of H-bonding is either too strong or too weak.(Reactions 1-3,9 in Table.1),2.Complex hydrides:The hydrogen release from complex hydrides is too low.(Reactions 4-8 in Table.1),3.Sorbent systems:The weak,van,der,Waals,interaction between molecular hydrogen and the sorbent for carbon-based materials and metal-organic frameworks.(Reactions 10-12 in Table.1),Comparison of gravimetric and volumetric densities of various hydrogen storage materials.,Fig.2,Reprinted from Ref.2,High hydrogen volumetric capacity(150g H2/L),High hydrogen gravimetric capacity(19 wt%),Solid form in ambient condition(110C-114),Producing hydrogen reaction on-board directly(70),Chemical hydrides:Ammonia,Borane,(AB),2.Background on Ammonia,Borane,2.1Pathways for ammonia,borane,synthesis and decomposition:,Synthesis:,Decomposition:,nNH3BH3(NH2BH2)n+(n-1)H2(500),BH2(NH3)2BH4+NH4Cl (add:diethyl ether)BH2(NH3)2Cl+NH3BH3+H2,2.2 Efficient methods are needed to dehydrogenate ammonia,borane,to release hydrogen,(1)Solid state thermal decomposition,(2)Transition metal catalyzed dehydrogenation,(3)Ionic liquid catalyzed dehydrogenation,(4)Solution phase thermal decomposition,(5)Nanophase ammonia,borane,encapsulated in,mesoporous,silica channels,3.Recent Studies of Ammonia,Borane,1,2,3,Determining AB physical properties and computational studies of AB structure,Dehydrogen,mechanism of ammonia,borane,studies,Ammonia,borane,-based hydrogen storage materials development,3.1 Ammonia-,borane,:physical properties,X-ray diffraction,neutron powder diffraction,inelastic neutron scattering,IR,Raman,microwave spectroscopy,NMR spectroscopy,Physical properties:,structure,phase transition,elastic constant,bond distance,vibration mode,Variation in the molecular volume and unit cell dimensions as a function of temperature and pressure.,Fig.2,Reprinted from Ref.3,Pmn21 Orthorhombic,I4mm Tetragonal,Left:Three,-dimensional Fourier difference maps calculated after refining boron and nitrogen atoms.Reprinted from Ref 4 Bowden X-ray,Bottom:The,evolution of the crystal structure with temperature projection on the,b,-,c,plane.Reprinted from Ref 5 J.B.Yang powder neutron diffraction,Left:,Rietveld,refinement profile for the Cmc2,1,phase of NH,3,BH,3,at 1.7,GPa,the structure is shown in the inset.Reprinted from Ref 3,Filinchuk,X-ray,Phase transitions determined at 5,kbar,and 14,kbar,by,Trudel,and Gilson,Ref 6,shortly after confirmed at 8,kbar,by,Custelcean,and,Dreger,Ref 7,Lin and coworkers,Ref 8,found three transitions,at 2,5,and 12,GPa,using the Raman spectroscopy.,Left:,Dihydrogen,bonding network in(up)orthorhombic BH3NH3,and(down)a possible network for tetragonal BH3NH3.Only a single layer of atoms close to a plane perpendicular to,c,is shown in each case.The BH3 groups bonded to the NH3 groups shown are above this plane,while NH3 groups bonded to the BH3 groups shown are below.Reprinted from Ref 4 Bowden X-ray,The major experiments determined,dihydrogen,bond equal about 2.02,(the,van,der,Waals,radii of 2.4,),may a,ccount for AB comparatively high melting point.,3.2 Dehydrogenation mechanism of ammonia,borane,3.3 Ammonia,borane,-based hydrogen storage materials studies,Unit cells of solid,LiAB,AB Reprinted from Ref 6,Bond length:,LiAB,AB possesses weakened,dihydrogen,bond both within the,LiAB,layers and within the AB layers,resulting in a lower stability of,LiAB,AB,4.Further work,*,*,*,5.Reference,1.High capacity hydrogen storage materials:attributes for automotive applications and techniques for materials discovery,J.Yang,Chem.Soc.Rev,.,2010,39,656.,2.InitiativeControl of Hydrogen Release and Uptake in Condensed Phases,N.Hess,EERE Program Review,2006.,3.High-pressure phase and transition phenomena in ammonia,borane,NH,3,BH,3,from X-ray diffraction,Landau theory,and,ab,initio,calculations,Y.Filinchuk,Phys.Rev.B,2009,79,214111.,4.Room-Temperature Structure of Ammonia,Borane,M.Bowden,Aust.J.Chem,.,2007,60,149,5.Structural evolution of ammonia,borane,for hydrogen storage,J.B.Yang,Appl.Phys.Lett,.,2008,92,091916.,6.Understanding from First-Principles Why LiNH2BH3 NH3BH3 Shows Improved Dehydrogenation over LiNH2BH3 and NH3BH3,W.Li,J.Phys.Chem.C,2010,114,19089,Thank you,