k asakura - kekpf · 2011. 5. 27. · they accelerate chemical reaction without changing themselves...
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Ultrafast analysis of catalyst surface
K Asakura
Catalysis Research Center, Hokkaido University, Kita-ku N21W10, Sapporo, Hokkaido 001-0021, Japan
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Polymers and plastics are generate using Catalysts (Ziegler Natter or Kaminsky catalysts)
Automobile catalysts (Pt-Pd-Rh/Al2O3, Pt/CeO2) Photocatalysts(TiO2) Enzyme Fuel cell electrode
What are catalysts?
Automobile catalyst To remove NOx From exhausted gas
They accelerate chemical reaction without changing themselves and important in many fields.
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Three important factors in catalysis
Activity rate determining step Slowest process.
Selectivity ex. Propane oxidation
• No selectivity CO2• High selectivity CH2CHCHO
Life time
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Classification of Catalysts
Solid State Catalysts-Heterogeneous catalysts Pt-Rh-Pd/Al2O3 Solid surface plays an important role
Catalyst in Solution Homogeneous catalysts Cross coupling catalysts, Enzyme Chiral synthesis, Metatheses Metal active site is important
Special Active Site Plays an important role.
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Miyaura-Suzuki Reaction
Oxidative addiition
transmetalation
Reductive elimination
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Classification of Catalysts
Solid State Catalysts-Heterogeneous catalysts Pt-Rh-Pd/Al2O3 Solid surface plays an important role
Catalyst in Solution Homogeneous catalysts Cross coupling catalysts, Enzyme Chiral synthesis, Metatheses Metal active site is important
Special Active Site Plays an important role.
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Heterogenous Catalysts
Langmuir Hinshellwood mechanism Horiuchi-Polanyi Mechamism
H2
CH2=CH2 H H CH2-CH3 H
CH3-CH3CH2=CH2
Catalysts
Adsorption Diffusion Reaction
Desorption
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From Unused Biomass to Fuel(A.Fukuoka Angewandte Chem. 2007)
Wood Celulose Solvitol
Alcohols
Gasoline
Plastics
CO2PlantsPhotosynthesis
Pt Catalyst
Fine Chemicals
glucose
Hemicelulose
5C sugarEnzyme
New Chemical industry based on biomassPF-ERL
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Environment Improvement Catalysts
)
mol )
50
40
30
20
10
0100806040200
3DOM-WO3
WO3
二 m
ol )
50
40
30
20
10
0100806040200
3DOM-WO3
WO3NP-
Time / min
CO2
mol )
50
40
30
20
10
0100806040200
3DOM-WO3
WO3
)
50
40
30
20
10
0100806040200
3DOM-WO3
WO3NP-
Light
Photodegradation of VOC Ueda Ohtani et al. J.Material Chem. (2010)
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Soot combution on nanofibered LaMnO3Nanofibered
conventional
Li, S.; Kato, R.; Wang, Q.; Yamanaka, T.; Takeguchi, T.; W., U. Applied Catalysis B: Environmental 2010, 93, 383.
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Rh dimer catalysts (Active for ethylene hydroformylationreaction)K. Asakura, K.K. Bando, Y. Iwasawa, H. Arakawa, K. Isobe, J.Am.Chem.Soc 112 (1990) 9096.
C2H4+CO+H2 C2H5CHO
4 6 8 10 12 14 16-0.20-0.15-0.10-0.050.000.050.100.15
k (
k)
K / 10nm-1
Rh Rh
CC
OO
RCp*
OO
SiO2
Rh Rh
C OR
Cp*
OO
SiO2
4 6 8 10 12 14 16
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
k (
k)
k /10 nm-1
H2RC2H5CHO
+CO,+R
0.270 nmm
IR吸収バンド1710 cm-1
IRabsorption band 2032,1969 cm-1
EXAFS before the reaction EXAFS after the adsorption
CO2
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.In-situ studies
Active site is dynamically changed during the reaction
In-situ studies are necessary to determine the reaction mechanisms.
High temperature and high pressure.
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Introduction
Sulfur compounds in fossil fuel. 1.Sulfur is oxidized to sulfurous or sulfuric
acids and is an origin for acid rain.2.It poisons the deNOX catalysts equipped in
cars. 3. Demand for use of low quality oil with high
sulfur contents.
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1990-1994 1995-2000 Post 2000
USA 500 ppm 500 ppm 15 ppm by 2006
Europe 500 ppm 500 ppm 50ppm by 200510 ppm by 2008
Japan 0.2 wt% 500 ppm 50 ppm by 200510 ppm by 2007
Sulfur in fuel is legally restricted more and more strictly.
http://www.epa.gov/apti/course422/ap7b1.html
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s
s
H2+ H2S
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Metal phosphides
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0
20
40
60
80
100
Con
vers
ion
/ %
S
N
HDSHDN
Fe2P/SiO2 MoP Ni2P/SiO2CoP/SiO2 WP Ni-Mo-S/Al2O3
More active than commercially avaialbe NiMoS
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In situ EXAFS .
High pressure cellJ.Phys. Chem.93,4213(1989)
Z.Phys.Chem.,144,105(1985).
Thermocouple
HeaterWater
GasGas
Gas
Window(Acrylic resin)
O-ringQuartz Tube
SampleWater
Water
Water
X-ray
Io I
J.Synchro.Rad.8, 581(2001).J.Chem.Phys. 70 (1979) 4849.
X-ray absorption, Principles, applications, techniques of EXAFS, SEXAFS, and XANES, New York, John Wiley & Sons, 1988.
X-ray windows are set far away from sample.
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Experimental SetupPF-ERL 2011/04/27
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X-rayInfraredThermocouple
Gas injection bulb
Heater
IR and X-ray hit the sampleSample : Ni2P/MCM-4135 mg,15 mm in diameter
Heating803 K by heaterGas introduction
Sample
反応 : C4H4S + 2H2 → C4H8SC4H8S + H2 → H2S + C4H8
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Experimental SetupMCT
InterferometerOptical faiber
IR
X-ray
QMS
Gas controller
ActivitiyQMS
Gas flow
StructureQXAFS
AdsorptionFT-IR
Reaction Cell
KEK, PF BL-9C
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EXAFS of Ni2P under reaction conditions.
2 4 6 8 10 12-0.1
0.0
0.1
0.2
b)
a)
(k)
k / A-1
Before reaction
10 h 4 6 8 10-0.004
-0.002
0.000
0.002
0.004
(k)
k / 10 nm-1
• Ni2P Ni K-edge XAFSDifference Spectrum
•Ni-S at 0.227 nm• with N=0.1.
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Difference spectra in HDS – before reaction
NiP
NiP
P
PNi
S PNi
P
NiP
P
PNi
P
• CF results of Ni-SR=0.227 nm; CN=0.1.
• Judging from the ratio of surface Ni to the bulk ~0.5 S/Ni=0.2±0.2
• Little reaction temperature dependence
k(k
) / 1
0nm
-1
0.00
0.02
0.04
0.06
0.08
0.10
0.12
k / 10 nm-13 104 5 6 7 8 9
Ni – S (FEFF)CN = 0.1, R = 0.227 nm, 2 = 0.0064 Å2
HDS at 513 K
HDS at 553 K
HDS at 593 K
Simulated XAFS based on Ni-S bond
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How does Ni-S bond change?
250 300 350 400 450 500 550 600
0.0
0.1
NN
i-S
T / K0 10 20 30 40 50 600.0
0.1
0.2
t / min
0.0
0.1
0.2
N
i-S
0.0
0.1
0.2
513 K
553 K
593 K
T / K 513 553 593
v/min-1 0.47(3) 0.8(3) 2.5(3)
•Ni-S is rapidly formed and saturated. •Saturation number is 0.1 •Ea=53 kJ/mol for formation reaction of Ni-S
0.1
Time and temperature dependence of Ni-S formation
Formation rate
Saturation number of Ni-S bond
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He HDS反応H2還元
He H2還元240 ℃
530 ℃H2S処理
H2還元
530 ℃
XANES, IR and MS changes during 513 K2B06
2010年9月16日20HDS反応開始
IR
Ni=SXAFS
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Reaction mechanisms
NiPS Formation processes
Ⅰ : Ni-Sformation
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Reaction mechanisms
Hydorgenation processes C-S bond cleavage
C-S bond cleavage
H2S
2H2
NiPS Formation processes
Ⅱ : Ni-SReaction
THT
H2S
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Reaction mechanisms
Hydorgenation processes C-S bond cleavage
C-S bond cleavage
H2S
2H2
Ⅲ : Steadystate
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Time resolved studies=>DXAFSPF-ERL
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• Stedy state- Mixture
• Reaction starts at once- Pump-probe- T-jump, P-Jump- Isotope change
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H.F.J.van’t Bilk, J.B.A.D.van Zon, T.Huizinga, J.C.Vis, D.C.Koningsberger, and R.Prins,J.Am.Chem.Soc., 107 (1985) 3139.
C
ORh
Rhx cluster
CO
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Disruption of Rh clusters on Al2O3 surface by CO at RT
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-4
-2
0
2
4
6420
The k3-weighted EXAFS Fourier transformed functions for Rh/Al2O3 under CO (26.7 kPa) at 298 K measured by DXAFS
together with the curve fittings of the observed FT data and their imaginary parts
-4
-2
0
2
4
6420
-4
-2
0
2
4
6420
0 s 0.6 s 3 s
-4
-2
0
2
4
6420R / 0.1 nm R / 0.1 nm R / 0.1 nm R / 0.1 nm
|FT|[
k3(
k)]
|FT|[
k3(
k)]
|FT|[
k3(
k)]
|FT|[
k3(
k)]
7 s
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(1) Suzuki, A.; Inada, Y.; M.; Nomura, M.; Iwasawa, Y.et al., Angewandte Chemie Inter.Ed. 2003, 42, 4795.
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The values of coordination number
(CN) and bond distance (R)
determined by the curve fitting as a function of CO exposure time
3.0
2.8
2.6
2.4
2.2
2.0
1.886420
Time / s
8
6
4
2
0
CN
R /
0.1
nmRh-Rh
Rh-Rh
Rh-O
Rh-O
Rh-C-(O)
Rh-(C)-O
Rh-CO
298 K
333 K
353 K
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(1) Suzuki, A.; Inada, Y.; M.; Nomura, M.; Iwasawa, Y.et al., Angewandte Chemie Inter.Ed. 2003, 42, 4795.
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Illustrative mechanism and time scale at 298 K for the disintegration oRh clusters on Al2O3 during CO adsorption by time-resolved DXAFS
Species A Intermediate B Intermediate C Species D
CO CO CO
600 ms 2000 ms 4000 ms
17 kJ/mol
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(1) Suzuki, A.; Inada, Y.; M.; Nomura, M.; Iwasawa, Y.et al. Angewandte Chemie Inter.Ed. 2003, 42, 4795.
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Tada, M., S. Murata, et al. (2007). Angewandte Chemie-International Edition 46(23): 4310-4315.
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Electrochemical trigger
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IF we have faster XAFS, what will do we obtain?
s-s Reaction intermediate
at-fs
ps-ns Atomic Dynamics
Electron DynamicsPF-ERL
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July 6 2009 6WCOC31
Spectroscopy and desorption analysisT. Matsushima, Surf. Sci.Reports 52 (2003) ; Surf. Sci. 603 (2009) 1415.
diffusion
OCO
Surface
CO2
① ② ③
STMEn
ergy
Distance from the surfacevibration
Rotation
Angle, translation
Transition stateO,CO
①
②
③
Spectrscopy
Transition state
Repulsive desorption → No equillibrium and information after reaction is maintained.
O
④
Analysis of desorbed species transition state information
STM Spectrscopy
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CO2 Desorption profile during CO +O reactionT. Matsushima, Surf. Sci.Reports 52 (2003) ; Surf. Sci. 603 (2009) 1415.
0 30 60 900
500
1000
1500
T Tr
ansl
atio
nal /
K
/ deg
[11b0]
[001] Interaction is large.
Pd(110) surface
[001]
0]1[1
0]1[1
[001]
Angle dependence of Translation energy
θcos30]1[1
[001]θcos10
Fastest
Slowest
Pd(110)
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July 6 2009 6WCOC33
IR EmissionK. Nakao, K. Kunimori, et al. Catalysis Letters 85 (2003) 213; K. Nakao, K. Kunimori et.al., Catalysis Today 111 (2006) 316.
Position average of s and b
Symmetric stretch
Bending
s mode
b mode
a mode Antisymmetric stretch
vibrational
rotation
RotationArea
Tva=2090 KTvsb=2200 KTr=1000 K
Anti-mode
IR emission from desorbed CO2 from Pd(111) with dirrerent surface temperatures
Surface temp=850 K
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Desorption from Pd(110)
Repulsive force
0 20 40 60400
600
800
1000
1200
1400
1600
1800
T vibration
[11b0]
T / K
Angle / Deg
[001]
T vibration
Large interaction
Coming along trough
Coming from the ridge
T. Yamanaka et al. Phys.Rev.Lett. 100(2008) 026104.
T surfacerotation
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Mmechanical catalystGerhard Swiegers
Energy –control to timing- control
Perfect Catalyst100 % acitivity, 100 % selectivity, Self-
recovery(long life time)Like Enzyme
Selective excitation
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Reaction induced by STM on Pd(110)
CH2CH2
CH3CH3
H2
Dosing tunneling current on7 nA, 450 mV, 1sec—C-H excitation.
Y. Sainoo, Y. Kim, M. Kawai, J. Chem. Phys.120 (2004) 7249.
Y. Kim, M. Kawai,et.al. PhysRev.Lett. 89 (2002) 126104.
-360 mV dI2/dV2 image
C-HC-D
T B
T
B
STS
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FEL-IR-selective excitation of chemical bond
H. Kuroda,et.al. Free Electron Lasers 2002, 2003, pp. II.
1. If one can use a strong pulse source with long interval, one irradiates the sample without heating the sample.
2μs
2sMacropulse
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July 6 2009 6WCOC 38
0.167 nm(967 cm-1)
0.173 nm (814 cm-1)
Ethanol decomposition reaction on MoO3 induced by Pulse IR
1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00
1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00
Ethylene
Ethylene
Aldehyde
1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00
Waterethanol
0.173 nm(814 cm-1)
1.9 mJ
3.2 mJ
3.5 mJ1230 cm-1
814 cm-1
967 cm-1
S.Sato, M.G.Moula Jpn.J.Appl.Phys. 41-1 (2002) 118; Chem.Lett 33 (2004) 558; Bull.Chem.Soc.Jpn., 81 (2008) 836.
No resonance
C2H5OH CH3CHO, CO2, C2H4
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Problems are
How to control inhomogeneity of CatalysisTime scale and Spatial scale. Chaotic reaction processSingle shot
CO oxidation reactions on Pt(100)
Surface is well-defined single crystal
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Real catalysts are complicated
Multifunctional Porus
Kapoor, M. P.; Inagaki, S. Bull. Chem. Soc. Jpn. 2006, 79, 1463.FSM-16
Moro-oka, Y. and W. Ueda (1994) Advances in Catalysis 40: 233.
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4D (Time + spatial resolution) +spectroscopyÅーmm の広いダイナミックレンジ ps- ms sub eV
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Conclusions
Ultra fast will help us understand the atom dynamics of surfaces
Ultrafast monitoring may be helpful to control the surface reaction
4D is necessary to apply the ultarafasttechnique to catalysts.
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