Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2:...
Transcript of Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2:...
![Page 1: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/1.jpg)
13th Oxford School on Neutron Scattering
St. Anne's College, University of Oxford 2 - 13 September 2013
Chemical Applications of Neutron ScatteringPart 2
Mainly Inelastic Scattering:Spectroscopy and Dynamics
Alberto AlbinatiUniversity of Milan, Department of Chemistry
![Page 2: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/2.jpg)
Chemical Applications of Neutron Scattering
Part 2: Inelastic Scattering
• INS Spectroscopy: Transition Metals Hydrides
• Rotational Tunnelling and the Nature of the M-H2
Bond
• Combined use of Diffraction, Spectroscopy and ab-
initio calculations
• Hydrogen Storage
![Page 3: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/3.jpg)
Incoherent Scattering Cross Sections
( )224incoh b bσ π= −
•Incoherent Scattering arises from the random distribution of different isotopes with different scattering lengths.
•Incoherent Scattering depends on the correlation between the positions of the same nucleus at different times.
NO INTERFERENCE EFFECTS ≡ SPECTROSCOPY
![Page 4: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/4.jpg)
INS spectrum from a hypothetical molecular crystal
![Page 5: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/5.jpg)
Inelastic and Quasielastic Neutron Spectroscopy
∆E hτ π≈ 2
Time Scale τ Resolution ∆E Spectroscopic Technique
10-11 sec 10 - 100 meV Direct Geometry TOF
10-9 sec 0.3 - 20 meV Backscattering Crystal Analyzer
10-7 sec 5 neV - 1 meV Spin Echo
Q =4πλ
ϑsin
MomentumTransfer Q(Å-1)
Distance (Å) Regime
0.05 100 Continous or Macrospic Diffusion
5 1 Atomic or Microscopic Diffusion
![Page 6: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/6.jpg)
INELASTIC INCOHERENT NEUTRON SCATTERING:
•The energy of the thermal neutrons is comparable to that of the lattice and molecular vibrations.•The incoherent part of the scattering cross-section (σinc) arises from the random distribution of different isotopes with different scattering lengths.
•The incoherent part of the scattering cross-section describes the singleparticles dynamics: Vibrational and rotational spectroscopy.•The intensity scattered by each mode depends on the value of the incoherent scattering cross-section ( σinc ) and the atomic displacements.•The incoherent cross section for Hydrogen is very large: modes involving H atoms will dominate the INS Spectrum
σinc (H) = 80.27 (barn)
σinc (D) = 2.05 (barn)
σ(inc) σ(coh) σ(abs)
![Page 7: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/7.jpg)
Inelastic neutron scattering measures atomic motion
22 )' ( ,coh
coh
d kb Nd dE
Sk
ωσω
=
Q
22 )' ( ,incoh
inc hi
o
d kb Nd dE k
Sω
ωσ =
Q
Inelastic coherent scattering measures correlated motions of atoms
Inelastic incoherent scattering measures self-correlationse.g. vibrations, diffusion
( )1 ( , ), )2
( i tG t e d dtS ωωπ
−= ∫∫ Q rQ r r
( )1 ( , )2
( , )ii t
sG t dS e d tω
πω −= ∫∫ Q rr rQ
![Page 8: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/8.jpg)
Correlation Functions
Scoh (Q, ω) F.T. G (r, t)
Sinc (Q, ω) F.T. Gs (r, t)
• G(r, t) ≡ Probability of finding an atom at r and at time t when there is an atom at r = 0 at t = 0.
• Gs(r, t) ≡ Probability of finding an atom at r and at time t if the same atom was at r = 0 at t = 0.
![Page 9: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/9.jpg)
INCOHERENT INELASTIC NEUTRON SCATTERING
( ) ( )2d 1 , ,
d d 4f
coh coh inc incf i
kS S
E kσ σ ω σ ω
π= + Ω
Q Q
( )( ) ( )( ) ( ) ( )
22 ' 2 2 2
,
1 1d 2 2 x . expd d 2
inc jinc rj r
j rj r
n bk Q uE k m
σ δ ω ωω
+ ± = −
Ω ∑ ∑q
q Q u qq
( ) ( )2 22 '2d 1 1 exp 2
d d 2 2 2inc
inc
Q u Zk b n W NE k m
ωσω
= + ± − Ω
2 '2d ( , )
d dinc
inc inck b S
E kσ ω=Ω
Q ( ) ( )2 2, exp 2incS Q u Wω = −Q
for a powder sample we can average
at very low T for hydrogenous materials
![Page 10: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/10.jpg)
![Page 11: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/11.jpg)
![Page 12: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/12.jpg)
The INS Difference-Spectrum of [P2N2Zr]2 (µ-H)(µ-N2H)
21 2 coth
8 2h hu
kTν
π µν =
![Page 13: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/13.jpg)
The Structure of [Co(CO)15H]−
D. Hart & al.JACS 1981, 103 1458
[Co6(CO)15]2- + H+ → [HCo6(CO)15]-
NMR (solution) δ ~ +3
Hydride δ ~ -5 -40
Formyl δ ~ +5 +10
![Page 14: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/14.jpg)
Cs[Co6(CO)15H]IN1 - ILL (30g)J. Howard (1983)
I.R. K[Co6(CO)15H] (CsI )Longoni & Stanghellini (1987)
K[Co6(CO)15H]Be Filter - LANSCE (1987)
800 1400 cm-1
15 K
![Page 15: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/15.jpg)
TOSCA
TFXA
![Page 16: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/16.jpg)
TOSCA at ISIS
![Page 17: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/17.jpg)
INS & I.R. Spectra of X[Co6(CO)15H]
K[Co6(CO)15H] in CsI
900 1000 1100 1200 1300 1400-0.1
0.0
0.1
0.2
0.3
0.4
0.5
S(Q
,ω) (
a. u
.)
ω (cm-1)
H-D PPNCo6[CO]15 DFT calculation
T = 20K
![Page 18: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/18.jpg)
INS & I.R. Spectra of X[Co6(CO)15H]
K[Co6(CO)15H] in CsI
900 1000 1100 1200 1300 1400-0.1
0.0
0.1
0.2
0.3
0.4
0.5
S(Q
,ω) (
a. u
.)
ω (cm-1)
H-D PPNCo6[CO]15 DFT calculation
T = 20K
![Page 19: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/19.jpg)
H-H Distances (Å) vs. JHD (Hz)
W(CO)3(PiPr3)2(H2) 0.82 (1) 34.0
[Fe(dppe)2(H)(H2)]+ 0.82 (2) 30.5
[Ru(dppe)2(H)(H2)]+ 0.82 (3) 32.0
[Os(dppe)2(H)(H2)]+ 0.79 (2) 25.5
d (H-H) JHD
![Page 20: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/20.jpg)
INS Spectra of M-(H2) Complexes
![Page 21: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/21.jpg)
M-(η2-H2) Bonding
![Page 22: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/22.jpg)
Non-classical Hydrides and Rotational Tunnelling Spectroscopy
![Page 23: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/23.jpg)
Rotational Tunnelling: Single Particle Rotation
For a single particle model (i.e.: V(ω) describes the system):
i i iεΗΦ = Φwhere
2 ( )B V ϕΗ = ∇ +
( )( ) 1 cos2j
V jV jn nϕ ϕ= −∑ n=2 twofold potentialn=3 threefold potential
2 / (2 )B I=
B: H2 (7.3 meV) > NH4+, NH3 (0.782 meV) > CH4, -CH3 (0.655 meV)
The level splitting is proportional to V(φ) and B
![Page 24: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/24.jpg)
Single Particle Rotation: Twofold potential
For a 1D rotor in a twofold-potential:
21( ) cos 22V Vϕ ϕ=
2
221 cos 22B V Eϕ
ϕ ∂− + Ψ = Ψ ∂
Eigenvalues (in units of B) are determined by the ratio V(f)/B
W. Press Single Particle Rotations in Crystals (Springer)Prager, Heidemann Chem. Rev. 97, 2933 (1997)
![Page 25: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/25.jpg)
The new IN5 Spectrometer
![Page 26: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/26.jpg)
INSTITUT MAX VON LAUE - PAUL LANGEVIN
Detectors
Effective Height 3.0 m~3000 L 3He + 570 L CF4
4.75 bar 3He + 1.25 bar CF4
147.5° Hor - ± 20.55° vert
![Page 27: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/27.jpg)
Rotational Tunnelling in [Fe(H)2(H2)L3] and [Ru(H2)(H)(dppe)2]+
![Page 28: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/28.jpg)
Rotational Tunnelling in Ru(H2)2(H)2(Pcyp3)2
-1.0 -0.5 0.0 0.5 1.00.00
0.02
0.04
S(Q
,ω)
energy transfer, meV
RuH6,λ=6.5Α 4K 32K 43K 53K
![Page 29: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/29.jpg)
Rotational Tunnelling in Ru(H)2(H2)2L2
L = P(cyp)3L = P(cy)3
-0.6 -0.4 0.0 0.4 0.6meV
L = P(cy)2(tBut)
Vφ = 0.99, 1.09 kcal/mol
![Page 30: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/30.jpg)
VIBRATIONAL FREQUENCIES and TUNNEL SPLITTINGS for M-H2 COMPLEXES
Compound ν(H-H) τ(H-H) ωt Vt[cm-1] (IR) [cm-1] [cm-1] [kcal/mol]
W(CO)3(P iPr3)2(H)2 2695 370 - 340 0.73 2.4
W(CO)3(PCy3)2(H)2 2690 380 - 325 0.89 2.2
[Fe(PP3)(H)(H2)]+ 276 - 259 1.15 1.9
[Ru(PP3)(H)(H2)]+ 225 – 184 2.58 1.6
IrBr(P iPr3)2(H)2(H2) 18.9 0.53
IrI(P iPr3)2(H)2(H2) 9.8 0.98Ir
P
PX
H HH
H
![Page 31: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/31.jpg)
[(CH3)4Pb] Prager, Heidemann Chem Rev (1997)
![Page 32: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/32.jpg)
(iPr3P)2IrI(H)2(H)2
![Page 33: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/33.jpg)
Dihydrogen-Hydride Exchange in (iPr3P)2IrX(H)2(H)2
Ir
R3P
PR3
H(1)
H(2)
H(3)H(4)
X Ir
R3P
PR3
H(1) H(2)
H(3)
H(4)
X
A
Ir
R3P
PR3
H(1)H(2)
H(3)
H(4)
XB
Ir
R3P
PR3
H(1)
H(2)
H(3)
H(4)
X
C
Ir
R3P
PR3
H(1)H(2)
H(3)
H(4)
X
![Page 34: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/34.jpg)
(iPr3P)2IrX(H)2(H)2
IrH
H
HH
X
PiPr3
PiPr3
X Cl Br I
Rotat. tunnelling freq. 20 19 6(ω, cm-1)
Rotat. barrier V2exp 0.51(3) 0.48(3) 1.00(4)
(kcal/mole)
Rotat. barrier Vcalc 0.37 (2.04) 0.42 (2.11) 0.66 (2.32)(PMe3 / PH3 kcal/mole)
H-H (exp) 0.78 (INS) 0.819(8) 0.856(9)
H-H (calc) 0.853 0.857 0.862
![Page 35: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/35.jpg)
(iPr3P)2IrX(H)2(H)2: Observed and CalculatedExchange Energies (QENS & B3LYP)
Data @ 100, 175, 210, 250 K ∆Ea = 1.5(2) Kcal/mol
B3LYP/BS4 (reactant, intermediate, TS’s)∆ETS = 1.87 kcal/mol
![Page 36: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/36.jpg)
Dihydrogen-Hydride Exchange in (iPr3P)2IrX(H)2(H)2
Ir
R3P
PR3
H(1)
H(2)
H(3)H(4)
X Ir
R3P
PR3
H(1) H(2)
H(3)
H(4)
X
A
Ir
R3P
PR3
H(1)H(2)
H(3)
H(4)
XB
Ir
R3P
PR3
H(1)
H(2)
H(3)
H(4)
X
C
Ir
R3P
PR3
H(1)H(2)
H(3)
H(4)
X
![Page 37: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/37.jpg)
Rotational Tunnelling in Ru(H2)2(H)2(Pcyp3)2
*( )
0( )E T
kTT e − Γ = Γ
-1.0 -0.5 0.0 0.5 1.00.00
0.02
0.04
S(Q
,ω)
energy transfer, meV
RuH6,λ=6.5Α 4K 32K 43K 53K
ω = 0.73 0.83 meVV = 0.99 1.09 kcal/mol
E* = 1.6 kcal/molH/H2 exchange
![Page 38: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/38.jpg)
H/H2 Exchange Mechanism
ΔE†(exp) = 1.65 KcaΔE†(calc) = 2.7 Kca
![Page 39: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/39.jpg)
Rotational Tunnelling and QENS for Tp*Rh(H2)H2
2 4 6 8 10 12 14
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
Ln(W
L)
1000/T
Ea=0.23kcal/mol
Ea=0.42kcal/mol
ω = 0.8 meV
![Page 40: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/40.jpg)
Tp*Rh(H2)H2: Exchange Path
E* = 3.9 kcal mol-1
![Page 41: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/41.jpg)
Classical vs. non-classical: [PP3Co(H)2]+ and [ PP3Co(H2)]+
Co
P
HP
PP
Co
P
PP
P
H H
Co
P
HP
PP
H
PF6- BPh4
-
Red solid White solid
HOTf THF
![Page 42: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/42.jpg)
White Form: [PP3Co(H)2]BPh4
Co – H 1.47 (7) Å (av)
![Page 43: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/43.jpg)
Red Form: [PP3Co(H)2]PF6
H – H 0.65(8) Å 0.807 Å (calc)
![Page 44: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/44.jpg)
![Page 45: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/45.jpg)
Red Form: [PP3Co(H)2]PF6White Form: [PP3Co(H)2]BPh4
![Page 46: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/46.jpg)
[PP3Co(H)2]BPh4 – H.P. Raman Spectrum
1500 1600 1700 1800 1900 2000 2100
0
2000
4000
6000
8000
10000
Pressure evolution of the H-Co-H stretching
Pressure (kbar)
23.0
20.8
18.8
16.2
13.2
10.7
8.8
6.0
4.6
1.9
Raman shift (cm-1)
![Page 47: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/47.jpg)
The Hydrogen Storage Problem
![Page 48: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/48.jpg)
Hydrogen as an Energy Vector
•Jules Verne The Mysterious Island (1 874).“… hydrogen and oxygen which constitute [water], used singly or together, will furnish an inexhaustible source of heat and light…”
•Max Pemberton The Iron Pirate (1 893).hydrogen from coal “ …fuels the most powerful engines
that have yet been placed on a battleship …”
![Page 49: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/49.jpg)
Hydrogen Production
Burning 3.8L gasoline produces ~ 9Kg of CO2
Energy wise 3.8L gasoline ~ 1Kg of H2
CH4 + H2O CO + 3H2CO + H2O CO2 + H2
H2/CO2 = 2/1
•Biomasses•Photovoltaic•Electrolysis + Nuclear Power (Solar Energy)
J.J. Romm “The Hype about Hydrogen” (2004) Ch.4
1 Kg of H2 by electrolysis ≡ 32 Kg of CO2
![Page 50: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/50.jpg)
Thermodynamics and kinetics of the adsorption /desorption process. -20<Qst(∆H) <-40 kJ/mol H2; Dchem>10-9cm2/s.
Capacity >6% wt, 60kg H2/m3 at RT, P<100 bar. ∼ 10% wt , at least, for the bare storage material itself.
Structural stability upon cycling/activation; Resistance against poisoning agents H2O, CO, CO2, N2, etc. Cost and Environment safety.
Parameters Values and Methods
Microscopically probe the interactions between H2 and individual adsorption sites – INS and Model calculations .
![Page 51: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/51.jpg)
![Page 52: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/52.jpg)
Proposed H2 Storage Materials
Mg2NiH4 LaNi5H6 H2(l) H2 (200 atm)
4Kg Hydrogen
2NaAlH4 2NaH + 2Al + 3H2↑
[Weller (2006)]
[Yaghi (2001)]
[Chem. Rev. (2004, 2012)]
![Page 53: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/53.jpg)
0 20 40 60 80 100 1200.0
0.2
0.4
0.6
0.8
1.0
-9
-20
-17
-22
-23
Frac
tiona
l Site
Occ
upan
cy
Pressure, bar
-33, -31-35kJ/mol H2
-26
Van der Waals–a few kJ, electrostatic-<10 kJ/mol H2
Graphite, activated carbons, CarbonNanotubes, Na+ , Li+… -exchangedZeolites
Interstitial hydrides-LaNi5, Non-classical hydrides: M-(η2-H2) complexes of Transition Metals
Very likely a combination ofelectronic and dispersiveinteractions. Most challenging tomodel and characterize. It washoped that MOF’s would fall here.
Expected Interactions and Associated Thermodynamics
![Page 54: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/54.jpg)
Rotational Energy Levels of the Hydrogen Molecule
Symmetry Properties Rotational Energy LevelsE = BJ(J+1)
![Page 55: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/55.jpg)
Introduction of a Barrier to Rotation of the H2 Molecule
![Page 56: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/56.jpg)
H2 Absorption in Nanoporous Materials
J. Eckert & al. JACS (2005)
8 10 12 14 16 18 20
S(Q,ω)
, arb.
units
Neutron energy loss, meV
SWNT
AC
Graphite
SWCNT
![Page 57: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/57.jpg)
0 20 40 60 80 100 1200.0
0.2
0.4
0.6
0.8
1.0
-9
-20
-17
-22
-23
Frac
tiona
l Site
Occ
upan
cy
Pressure, bar
-33, -31-35kJ/mol H2
-26
Van der Waals–a few kJ, electrostatic-<10 kJ/mol H2
Graphite, activated carbons, CarbonNanotubes, Na+ , Li+… -exchangedZeolites
Interstitial hydrides-LaNi5, Non-classical hydrides: M-(η2-H2) complexes of Transition Metals
Very likely a combination ofelectronic and dispersiveinteractions. Most challenging tomodel and characterize. It washoped that MOF’s would fall here.
Expected Interactions and Associated Thermodynamics
![Page 58: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/58.jpg)
Chemisorption of H2 in Fe -ZSM-5
ω = 4.2(2) cm-1 8.3(2) cm-1
NEAT @5K - λ = 5.1Å
Van der Sluys & al. JACS 1990, 112, 4831
![Page 59: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/59.jpg)
Chemisorption of Molecular Hydrogen in: Cu–ZSM5H2/Cu 0.4
H2/Cu 2.0
ωτ ±0.80 cm-1 ±1.37 cm-1
IN5 @4K - λ = 7.0Å
-0.5 0.0 0.5
10 ÷4 K
45 ÷10 K
92 ÷47 K150 ÷92 K
200 K
![Page 60: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/60.jpg)
Dihydrogen Adsorption Isotherms - H2 in Cu-ZSM5
Isosteric Heat of adsorptionH2 on Cu 39±4 - 73±4 kJ/mol
Pressure, bar0 14
H2/Cu
Q in
kJ/
mol
Abso
rbed
H2,
cc (S
TP)
:
Chem Phys Lett 449, 182 (2007)
![Page 61: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/61.jpg)
Molecular Chemisorption at Unsaturated Transition Metal Binding Sites
Sorption Based Materials with Greater H2 - Binding Energy
(can reach > 20 kJ/mol)
⇓ ⇓ ⇓Bind Multiple DihydrogenLigands
Lighter Metals: alkali,alkaline earth hybrids
Density too high? Not enough binding sites?
Framework modifications: anionic frameworks, different metals…
⇓Combine two or more of these approaches in one material
![Page 62: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/62.jpg)
![Page 63: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/63.jpg)
The Effect of Framework Catenation
PCN-6 (15K) PCN-6’ (15K)
JACS (2008)
![Page 64: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/64.jpg)
O. Yaghi (2010)O. Yaghi (2010)
![Page 65: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/65.jpg)
Weak-H2 Chemisorption - HKUST-1
Peak at ~ 9.1 meV
Cu-BTCAimed at achieving heats of
adsorption of ~20 kJ/mol H2
S.S.-Y. Chui et al. Science 283, 1148 (1999)
![Page 66: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/66.jpg)
ZIF-68
ZIF-69
ZIF’s: Zeolite Type Frameworks
Cl substitution on benzene ring in ZIF-69Banerjee & al. Science 319, 939, 2008.
-2
0
2
4
6
8
10
12
14
16
0 100 200 300 400 500 600 700 800P (torr)
Up
tak
e (
mg
g-1
ST
P)
Adsorption-69
Desorption-69
Adsorption-68
Desorption -68Adsorption-70
Desorption-70
ZIF-70
![Page 67: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/67.jpg)
INS of H2 in ZIF-68, ZIF-69
Possible binding sites: ZnN4 cluster, Im, -NO2, organic, and -Cl (ZIF-69)
NEAT Spectrometer (BENSC) T = 5K
![Page 68: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/68.jpg)
CPO-27-Co [Co2(dhtp)(H2O)•8(H2O)] (dhtp = 2,5- dihydroxyterephthalic acid)
P.C. Dietzel & al. Chem. Comm.(2006)
Georgiev, Albinati Eckert
![Page 69: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/69.jpg)
CPO-27- M[M2(dhtp)(H2O)•8(H2O), M = Mg, Ni, Co]
(dhtp = 2,5- dihydroxyterephthalic acid)
Georgiev, Albinati Eckert
![Page 70: Chemical Applications of Neutron ScatteringChemical Applications of Neutron Scattering. Part 2: InelasticScattering ... •The energy of the thermal neutrons is comparable to that](https://reader031.fdocuments.us/reader031/viewer/2022013021/5f048bc47e708231d40e8136/html5/thumbnails/70.jpg)
Dr. S. Rizzato, University of Milan
Dr. P. A. Georgiev, University of Milan
Dr. T. F. Koetzle, Argonne National Laboratory
Dr. W. Klooster, Amethyst Scientific Consulting LLP, Singapore
Dr. S. Capelli, Institut Laue – Langevin
Dr. S. A. Mason, Institut Laue – Langevin
Dr. G. J. McIntyre, Institut Laue – Langevin
Dr. J. Ollivier, Institut Laue – Langevin
Dr. J. Eckert, Los Alamos National Laboratory
Prof. P. S. Pregosin. ETH – Zürich
Prof. H. Berke, University of Zürich
Dr. B. Chaudret, CNRS Toulouse
Dr. S. Sabo - Etienne, CNRS Toulouse
Dr. M. Grellier, CNRS Toulouse
Prof. B. L. Mojet, University of Twente
Prof. K. C. Caulton, Indiana University
Prof. M. B. Hall, Texas A&M
Prof. R. Morris, University of Toronto
Funded by:
C.N.R., M.U.R,
EU FP5-RTM, NATO