Catalyst Preparation
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How to make catalysts
WS 07 Cat React Eng Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Agenda Use of suported catalysts
What are weak points
Traditional catalyst preparation methods
Why can that be made better?
Novel functionalization methods One-step methods 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Criteria for a good catalyst Chemistry related
Non-chemical
activity
stability
selectivity
morphology
thermal characteristics
mechanical strength originality cost
27. April 2005
Catalyst Preparation
Why supported catalysts? Most active materials are NOT:
Mechanically or thermally stable
of a open morphology
of low cost
Æ Good for making rings Æ Useless Catalysts
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst preparation
Æ Good and stable dispersion necessary 27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Traditional (1) Produce a support with a high surface area (2) Functionalize support using large range of surface methods
Classical: Grafting, Precipitation, Impregnation
Modern techniques: Vapor deposition, layer deposition
27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Supports – keeping activity at the right place Goal: optimal dispersion for active component and stabilisation against sintering
How: Using ultra hard and chemically unreactive materials with high melting points (SiO2, TiO2, Al2O3, Carbon….)
With a large surface area (10-? m2/g)
27. April 2005
How big is the SSA of a single carbon graphene sheet?
Graphite STM Image
ρ ~ 2160 kg m-3 Interlayer distance = 0.335 nm
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Methods for preparation of supports “anorganic materials at large scale” Solid state reactions (precipitation, drying, coagulation) Reduction, carbonization, leaching Sol – gel (reactive chemistry) Flame hydrolysis of chloride (high temp + gas phase)
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Reduction, carbonization: metallic phases Temperature controlled reaction Bed of precursor material (usually oxide MOx) Recative gases (H2, CH4, NH3…)
ΔT (500- 1500°C) ~ 4-12 h
Preparation of Catalytic bed (e.g. M, MNx, MCx)
27. April 2005
WC, MoC, W, Fe, CoN …
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Alloy leaching, larger surfaces: Raney nickel! Ni Alloy (e.g. AlNi) Solid solution
Quenching Precipitation Al
Digestion of less noble metal using NaOH
Porous Ni with low particle size (Raney Nickel) 27. April 2005
Catalyst Preparation
Sol-Gel: mostly oxides
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Zeolites Aluminiumsilicates
> 600 m2/gr
Solid acids
Trapping of Ions and metal complexes (ship in a bottle)
27. April 2005
Isomer selective synthesis
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Flame hydrolysis 2 H2 + O2 Æ H2O SiCl4 + H2O Æ SiO2 + 4 HCl
TiCl4, SnCl4, AlCl3, Fe(CO)5…
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Functionalization Traditional Chemical methods
Grafting
Precipitation
Impregnation
Modern methods (mostly from electronics industry)
Chemical and Physical Vapor Deposition
Atomic Layer Deposition
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Anchoring and Grafting Stable covalent bonds between homogeneous transition metal complex and inorganic support O
O M OH silica
+
MoCl5
473 K -HCl
OMoCl4 silica anchored species
27. April 2005
473 K -HCl
O O silica grafted species
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Impregnation Æ low loading Support, often porous grains
Dipping Drying, Reduction
calcination T circa 400°C Metal salt solution
Impregnated support
Active Catalyst 27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Precipitation Æ high loading
Change of T, pH or concentration Metal salt solution
ÆDecrease solubility of metal
Particle size of active species determined by solubility + supersolubility (see TVT) 27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Physical Vapor deposition (PVD) or “how to transfer metals from A to B”
27. April 2005
Catalyst Preparation
What is flame spray synthesis? Flame spray as a one step method to functionalized catalysts
Æ Flame spray •Use of an organic liquid precursor •Dispersing precursor with oxygen •Igniting the spray using a premix flame L. Madler, H. K. Kammler, R. Mueller, S. E. Pratsinis, J. Aerosol Sci., 2002, 33, 369. 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Gas phase synthesis of nanomaterials
© Reto Strobel Stark, W.J., Mädler L., Pratsinis S. E., WO 2004005184 27. April 2005
Catalyst Preparation
How useful is it?
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
How useful is it?
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Products Complex systems
Mixed oxides (e.g YAG)
Composites (e.g. Pt/CeO2/ZrO2)
Excellent product dispersion CeO2/ZrO2 transmission electron micrograph
J. Marchal, T. John, R. Baranwal, T. Hinklin, R. M. Laine, Chem. Mater., 2004, 16, 822. W.J. Stark, 27. April 2005 L. Madler, M. Maciejewski, S.E. Pratsinis, and A. Baiker, Chem. Commun., 2003, 588-9.
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
VOx / titania for DeNOx O2
NO + NH3
NOx removed / %
100
N2 + H2O
V/TiO2 flame synthesis
50
commercial material 0
100
150
200
250
Process temperature / °C
W. J. Stark, K. Wegner, S. E. Pratsinis, A. Baiker, J. Catal., 197, 182 (2001) W. J. Stark, A. Baiker, S. E. Pratsinis, Part. Part. Sys. Charact., 19, 306-311 (2002). 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Fine chemistry OH
OH OOH O
Ti/silica 1
2
Selectivity / %
100 90
Peroxid Olefin 1
80 70 60 50
Shell- Aerogel patent wet-phase
TS-1 6 g/h 150 g/h
500 g/h
flame-made Ti/SiO2
W. J. Stark, S. E. Pratsinis, A. Baiker, A., J. Catal., 203, 516 (2001). W. J. Stark, H. K. Kammler, R. Strobel, D. Günther, A. Baiker, S. E. Pratsinis, Ind. Eng. Chem. Res., 41, 4921 (2002). 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Highest purity catalysts result better selectivity OH
OH
TBHP (5)
100
O
60
40
2
OH
80
Co Cr Mn Fe
1
OH
20 10
100
1000
80
60
40
20
1
O
Lewis acid
(b)
Fe, Ti
TBHP (5)
Co Cr Mn Fe
O
OH
3 O
(c)
Cr, Co
10
Heavy metal content / ppm
4
100
1000
heavy metal content / ppm 0.5 O2 + H O
Cr, Mn, Fe, Co
5
W. J. Stark, R. Strobel. D. Günther, S. E. Pratsinis, A. Baiker, J. Mater. Chem. 12, 3620 (2002) 27. April 2005
(a)
Ti
1
olefin usage / %
peroxid usage / %
100
6
(d)
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
flame
100 75
commercial
50 25
0.8
1000
ee / %
75 50 E4759 (reference)
25
5Pt3/3 (this work)
0 0
50
100
time / min
150
200
dV/dlog(D) / cm3 nm-1 g-1
Conversion / %
Pt/alumina: 50 % less Pt required for enantioselective hydrogenations
0.6 0.4 0.2 0 1
10
Pore diameter / nm
R. Strobel, W. J. Stark, L. Mädler, S. E. Pratsinis, A. Baiker, J. Catal., 294-304, 213 (2002). 27. April 2005
5Pt3/3
E4759
100
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
High temperature stability ceramic materials
Ceria/zirconia for automotive exhaust gas cleaning
Composite materials Excellent cold-start less Pt/Pd/Rh
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Dyn. oxygen /mol kg
-1
0.5 Pt/ceria/zirconia Flame Wet phase
1.2 1.0 0.8 0.6
2 CeO2
0.4
CO H2
0.2 0.0 0
200
400
600
Ce2O3 + "O" CO2 H2O 800
1000
Temperature / °C 27. April 2005
1200
Reference powder prepared from precipitation and impregnation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Dyn. oxygen /mol kg
-1
0.5 Pt/ceria/zirconia: Thermal stability 1.2 1.0 0.8 0.6
st
Flame, 1 nd Flame, 2 st Wet phase, 1 nd Wet phase, 2
0.4 0.2 0.0 0
200
400
600
800
1000
Temperature / °C
27. April 2005
1200
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Morphology and particles size strongly influence the sintering stability Rhodia, 2004: fractal like structures of ceria based oxides:
Highest thermal stability.
14 m2/g for Ce/ZrOx after 1100 °C, 4h
23 m2/g for Pr-doped Ce/ZrOx after 1100 °C, 4h
Rohart et al, Rhodia Electronics & Catalysis, Top. Catal. 30/31, 2004. Engelhard WO 02/30546, OMG-DMC2 EP 1181970; Daihatsu EP 1174174; Delphi US 6378338; Engelhard WO 02/22242; Toyota EP 1172139 27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Larger flame spray burners
Pilot scale flame spray synthesis at 750 g / h
only 45 m2/g as prep. 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Large vs. small starting powders as prep.
1100 °C, 4 h, air
Lab scale,
120-160 m2/g for
4.5 m2/g
res. time 5-10 μsec
0.5 wt% Pt / CeZrO4
Pilot scale,
40-45 m2/g
26-29 m2/g
res. time >30 μsec
0.5 wt% Pt / CeZrO4
14 m2/g*
Rohart et al, Rhodia Electronics & Catalysis, Top. Catal. 30/31, 2004. Engelhard WO 02/30546, OMG-DMC2 EP 1181970; Daihatsu EP 1174174; Delphi US 6378338; Engelhard WO 02/22242; Toyota EP 1172139 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Large vs. small starting powders
Neck formation, local equilibrium
Rapid sintering
Rohart et al, Rhodia Electronics & Catalysis, Top. Catal. 30/31, 2004. Engelhard WO 02/30546, OMG-DMC2 EP 1181970; Daihatsu EP 1174174; Delphi US 6378338; Engelhard WO 02/22242; Toyota EP 1172139 27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Large vs. small starting powders
Rohart et al, Rhodia Electronics & Catalysis, Top. Catal. 30/31, 2004. Engelhard WO 02/30546, OMG-DMC2 EP 1181970; Daihatsu EP 1174174; Delphi US 6378338; Engelhard WO 02/22242; Toyota EP 1172139 27. April 2005
WS 07 Cat React Eng Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Agenda Use of suported catalysts
What are weak points
Traditional catalyst preparation methods
Why can that be made better?
Novel functionalization methods One-step methods 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Criteria for a good catalyst Chemistry related
Non-chemical
activity
stability
selectivity
morphology
thermal characteristics
mechanical strength originality cost
27. April 2005
Catalyst Preparation
Why supported catalysts? Most active materials are NOT:
Mechanically or thermally stable
of a open morphology
of low cost
Æ Good for making rings Æ Useless Catalysts
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst preparation
Æ Good and stable dispersion necessary 27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Traditional (1) Produce a support with a high surface area (2) Functionalize support using large range of surface methods
Classical: Grafting, Precipitation, Impregnation
Modern techniques: Vapor deposition, layer deposition
27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Supports – keeping activity at the right place Goal: optimal dispersion for active component and stabilisation against sintering
How: Using ultra hard and chemically unreactive materials with high melting points (SiO2, TiO2, Al2O3, Carbon….)
With a large surface area (10-? m2/g)
27. April 2005
How big is the SSA of a single carbon graphene sheet?
Graphite STM Image
ρ ~ 2160 kg m-3 Interlayer distance = 0.335 nm
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Methods for preparation of supports “anorganic materials at large scale” Solid state reactions (precipitation, drying, coagulation) Reduction, carbonization, leaching Sol – gel (reactive chemistry) Flame hydrolysis of chloride (high temp + gas phase)
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Reduction, carbonization: metallic phases Temperature controlled reaction Bed of precursor material (usually oxide MOx) Recative gases (H2, CH4, NH3…)
ΔT (500- 1500°C) ~ 4-12 h
Preparation of Catalytic bed (e.g. M, MNx, MCx)
27. April 2005
WC, MoC, W, Fe, CoN …
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Alloy leaching, larger surfaces: Raney nickel! Ni Alloy (e.g. AlNi) Solid solution
Quenching Precipitation Al
Digestion of less noble metal using NaOH
Porous Ni with low particle size (Raney Nickel) 27. April 2005
Catalyst Preparation
Sol-Gel: mostly oxides
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Zeolites Aluminiumsilicates
> 600 m2/gr
Solid acids
Trapping of Ions and metal complexes (ship in a bottle)
27. April 2005
Isomer selective synthesis
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Flame hydrolysis 2 H2 + O2 Æ H2O SiCl4 + H2O Æ SiO2 + 4 HCl
TiCl4, SnCl4, AlCl3, Fe(CO)5…
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Functionalization Traditional Chemical methods
Grafting
Precipitation
Impregnation
Modern methods (mostly from electronics industry)
Chemical and Physical Vapor Deposition
Atomic Layer Deposition
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Anchoring and Grafting Stable covalent bonds between homogeneous transition metal complex and inorganic support O
O M OH silica
+
MoCl5
473 K -HCl
OMoCl4 silica anchored species
27. April 2005
473 K -HCl
O O silica grafted species
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Impregnation Æ low loading Support, often porous grains
Dipping Drying, Reduction
calcination T circa 400°C Metal salt solution
Impregnated support
Active Catalyst 27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Precipitation Æ high loading
Change of T, pH or concentration Metal salt solution
ÆDecrease solubility of metal
Particle size of active species determined by solubility + supersolubility (see TVT) 27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Physical Vapor deposition (PVD) or “how to transfer metals from A to B”
27. April 2005
Catalyst Preparation
What is flame spray synthesis? Flame spray as a one step method to functionalized catalysts
Æ Flame spray •Use of an organic liquid precursor •Dispersing precursor with oxygen •Igniting the spray using a premix flame L. Madler, H. K. Kammler, R. Mueller, S. E. Pratsinis, J. Aerosol Sci., 2002, 33, 369. 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Gas phase synthesis of nanomaterials
© Reto Strobel Stark, W.J., Mädler L., Pratsinis S. E., WO 2004005184 27. April 2005
Catalyst Preparation
How useful is it?
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
How useful is it?
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Products Complex systems
Mixed oxides (e.g YAG)
Composites (e.g. Pt/CeO2/ZrO2)
Excellent product dispersion CeO2/ZrO2 transmission electron micrograph
J. Marchal, T. John, R. Baranwal, T. Hinklin, R. M. Laine, Chem. Mater., 2004, 16, 822. W.J. Stark, 27. April 2005 L. Madler, M. Maciejewski, S.E. Pratsinis, and A. Baiker, Chem. Commun., 2003, 588-9.
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
VOx / titania for DeNOx O2
NO + NH3
NOx removed / %
100
N2 + H2O
V/TiO2 flame synthesis
50
commercial material 0
100
150
200
250
Process temperature / °C
W. J. Stark, K. Wegner, S. E. Pratsinis, A. Baiker, J. Catal., 197, 182 (2001) W. J. Stark, A. Baiker, S. E. Pratsinis, Part. Part. Sys. Charact., 19, 306-311 (2002). 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Fine chemistry OH
OH OOH O
Ti/silica 1
2
Selectivity / %
100 90
Peroxid Olefin 1
80 70 60 50
Shell- Aerogel patent wet-phase
TS-1 6 g/h 150 g/h
500 g/h
flame-made Ti/SiO2
W. J. Stark, S. E. Pratsinis, A. Baiker, A., J. Catal., 203, 516 (2001). W. J. Stark, H. K. Kammler, R. Strobel, D. Günther, A. Baiker, S. E. Pratsinis, Ind. Eng. Chem. Res., 41, 4921 (2002). 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Highest purity catalysts result better selectivity OH
OH
TBHP (5)
100
O
60
40
2
OH
80
Co Cr Mn Fe
1
OH
20 10
100
1000
80
60
40
20
1
O
Lewis acid
(b)
Fe, Ti
TBHP (5)
Co Cr Mn Fe
O
OH
3 O
(c)
Cr, Co
10
Heavy metal content / ppm
4
100
1000
heavy metal content / ppm 0.5 O2 + H O
Cr, Mn, Fe, Co
5
W. J. Stark, R. Strobel. D. Günther, S. E. Pratsinis, A. Baiker, J. Mater. Chem. 12, 3620 (2002) 27. April 2005
(a)
Ti
1
olefin usage / %
peroxid usage / %
100
6
(d)
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
flame
100 75
commercial
50 25
0.8
1000
ee / %
75 50 E4759 (reference)
25
5Pt3/3 (this work)
0 0
50
100
time / min
150
200
dV/dlog(D) / cm3 nm-1 g-1
Conversion / %
Pt/alumina: 50 % less Pt required for enantioselective hydrogenations
0.6 0.4 0.2 0 1
10
Pore diameter / nm
R. Strobel, W. J. Stark, L. Mädler, S. E. Pratsinis, A. Baiker, J. Catal., 294-304, 213 (2002). 27. April 2005
5Pt3/3
E4759
100
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
High temperature stability ceramic materials
Ceria/zirconia for automotive exhaust gas cleaning
Composite materials Excellent cold-start less Pt/Pd/Rh
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Dyn. oxygen /mol kg
-1
0.5 Pt/ceria/zirconia Flame Wet phase
1.2 1.0 0.8 0.6
2 CeO2
0.4
CO H2
0.2 0.0 0
200
400
600
Ce2O3 + "O" CO2 H2O 800
1000
Temperature / °C 27. April 2005
1200
Reference powder prepared from precipitation and impregnation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Dyn. oxygen /mol kg
-1
0.5 Pt/ceria/zirconia: Thermal stability 1.2 1.0 0.8 0.6
st
Flame, 1 nd Flame, 2 st Wet phase, 1 nd Wet phase, 2
0.4 0.2 0.0 0
200
400
600
800
1000
Temperature / °C
27. April 2005
1200
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Morphology and particles size strongly influence the sintering stability Rhodia, 2004: fractal like structures of ceria based oxides:
Highest thermal stability.
14 m2/g for Ce/ZrOx after 1100 °C, 4h
23 m2/g for Pr-doped Ce/ZrOx after 1100 °C, 4h
Rohart et al, Rhodia Electronics & Catalysis, Top. Catal. 30/31, 2004. Engelhard WO 02/30546, OMG-DMC2 EP 1181970; Daihatsu EP 1174174; Delphi US 6378338; Engelhard WO 02/22242; Toyota EP 1172139 27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Larger flame spray burners
Pilot scale flame spray synthesis at 750 g / h
only 45 m2/g as prep. 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Large vs. small starting powders as prep.
1100 °C, 4 h, air
Lab scale,
120-160 m2/g for
4.5 m2/g
res. time 5-10 μsec
0.5 wt% Pt / CeZrO4
Pilot scale,
40-45 m2/g
26-29 m2/g
res. time >30 μsec
0.5 wt% Pt / CeZrO4
14 m2/g*
Rohart et al, Rhodia Electronics & Catalysis, Top. Catal. 30/31, 2004. Engelhard WO 02/30546, OMG-DMC2 EP 1181970; Daihatsu EP 1174174; Delphi US 6378338; Engelhard WO 02/22242; Toyota EP 1172139 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Large vs. small starting powders
Neck formation, local equilibrium
Rapid sintering
Rohart et al, Rhodia Electronics & Catalysis, Top. Catal. 30/31, 2004. Engelhard WO 02/30546, OMG-DMC2 EP 1181970; Daihatsu EP 1174174; Delphi US 6378338; Engelhard WO 02/22242; Toyota EP 1172139 27. April 2005
Catalyst Preparation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Large vs. small starting powders
Rohart et al, Rhodia Electronics & Catalysis, Top. Catal. 30/31, 2004. Engelhard WO 02/30546, OMG-DMC2 EP 1181970; Daihatsu EP 1174174; Delphi US 6378338; Engelhard WO 02/22242; Toyota EP 1172139 27. April 2005
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