Crystalline structure - Single crystal & Powder X-ray diffraction (XRD) - Electron crystallography Oxidation state & Coordination - X-ray absorption spectra - X-ray photoelectron spectra (XPS & Auger) - Solid state NMR ( mainly coordination) - IR & Raman ( mainly coordination) - UV-Vis spectra Elemental analysis- ICP-AES, XPS, EDX Surface area & Pore size - N 2 adsorption-desorption isotherm - Mercury Intrusion Porosimetry Morphology- SEM Pore structure- TEM Techniques for characterization of nano- porous materials
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Techniques for characterization of nano- porous …sfcheng/HTML/material94/...k d f k s k k c k i j j j j j j j j V R R f R N − ⋅ ⋅ + + ⋅ ⋅ − ⋅ = ∑ k a 2E photoelectron
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Crystalline structure- Single crystal & Powder X-ray diffraction (XRD)- Electron crystallography
Oxidation state & Coordination- X-ray absorption spectra- X-ray photoelectron spectra (XPS & Auger)- Solid state NMR ( mainly coordination)- IR & Raman ( mainly coordination)- UV-Vis spectra
Elemental analysis- ICP-AES, XPS, EDXSurface area & Pore size
If use higher field, e.g. 300 MHz ⇒ better resolution
0.999995
1.0
mI = -1/2
mI = +1/2
For 1H
I = 1/2
• High resolution NMR spectra of solids
ψψ E=Η
SRQCSJDRFZ Η+Η+Η+Η+Η+Η+Η=Η
external Hamiltonian internal Hamiltonian
HZ: Zeeman interaction of the nuclear magnetic moment with the applied field B0
HRF: interaction between nuclear spin & the time-dependent radio freq. field B1(t)
HD: dipolar interaction between nuclear magnetic dipole momentsHJ: e— mediacted nuclear spin-spin interactionHCS: chemical shift associated with electronic screening of nucleiHSR: spin-rotation interaction; I and molecular angular momentumHQ: nuclear spin & quadruple moment
not importantin solid
importantfor I > 1/2
A general Hamiltonian for the interactions experienced by a nucleus of spin I
HamiltonianWave function
eigenvalue
A general Hamiltonian for the interactions experienced by a nucleus of spin I in the solid state may be written as in equation (1.2)
H = HZ + HD + HCS + H SC + HQ (1.2)
0 ~ 109Quadrupolar
0 ~ 104Scalar Coupling
0 ~ 105Chemical Shift
0 ~ 105Dipolar
106 ~ 108Zeeman
Table 1.1 Approximate ranges of the different spin interactions (in Hz)
Zeeman interaction
ZNNzZ
ZZ
IHgIHH
HHHH
00
000 cos
βγ
µθµµ
−=−=
−=−=⋅−=
h
vv
=
==
Cme
g
IgI
PN
NN
2h
h βγµ
magnetogyric ratio
nuclear g factorBohr magneton of the particular nucleus
Dipolar interaction HD
IDIr
HHij
IIID
vvh⋅⋅== ˆ
3
22γ
internuclear distance
dipolar coupling tensor
magnetogyric ratio
For single type of spin, I
Chemical shift interaction
0ˆ HIH ICS
vvh ⋅⋅= σγ Proportional linearly to the applied field
Range of common isotropic chemical shift (ppm)
necleus
20031P
10019F
25013C
8029Si
35015N
201H
Table. Typical values of chemical shift
Spin-spin coupling interaction
SJIH SC
vv⋅⋅= ˆ
field independent and is usually smaller than the other interaction
Quadrupolar interaction
IQIHQ
vv⋅⋅= ˆ
nuclear electric quadrupole moment eQ
only when I > ½field independent
ν
ν
ν1
ν2
Dipolar Interaction
HD = 0, if 3cos2θij – 1 = 0
Magic Angle Spinning
(MAS)
Q4
Q3
Q2
Crystalline structure- Single crystal & Powder X-ray diffraction (XRD)- Electron crystallography
Oxidation state & Coordination- X-ray absorption spectra- X-ray photoelectron spectra (XPS & Auger)- Solid state NMR ( mainly coordination)- IR & Raman ( mainly coordination)- UV-Vis spectra
Elemental analysis- ICP-AES, XPS, EDXSurface area & Pore size
Techniques for characterization of nano-porous materials
△E = hνm
Vibrational Spectroscopy
IR Spectroscopy
IRstretching
bending
stretchingbending
stretchingbending
stretching
stretching
stretching
Faujasite
Ferrierite
ZSM-5
Raman Spectroscopy
Boltzman Distribution affects the intensity of Anti-Stocks
Anatase638
515 395
200400600800
Rutile445
608
200400600800
Fig. 3.2 FT-Raman spectra of TiO2 of anatase and rutile phases: (a) lab-made, and after calcination at (b) 400 ℃, (c) 700 ℃, in comparison to (d) ) commercially available.
(a)(a)
(b)(b)
(c) (c)
(d)
(d)
Conclusions
There are still a huge There are still a huge SPACESPACE in the research of in the research of nanonano--porous materials. porous materials.