How to make catalysts
WS 07 Cat React Eng Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Agenda
Use Use of supo suport rted ed cata cataly lyst sts s
What are weak points
Tradit Tradition ional al catal catalyst yst prepar preparati ation on method methods s
Why can that be made better?
Novel Novel functiona functionalizati lization on methods methods
OneOne-st step ep meth method ods s
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
Cri Criter teria for for a goo good cat catalys alystt Chemistry related
Non-chemical
activity
stability
selectivity
morphology
thermal characteristics
mechanical strength originality cost
27. April 2005
Catalyst Preparation
Why supported catalysts?
Most active mater terials are NOT:
Mech Mechan anic ical ally ly or ther therma mall lly y stab stable le
of a open open morpho morpholog logy y
of low low cos cost
Æ Goo Good
for for mak making ing rin rings
Useles ess s Æ Usel
27. April 2005
Cata Cataly lyst sts s
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
Cata Cataly lyst st pr prep epar arat atio ion n
Good Good and and sta stabl ble e disp disper ersi sion on nece necess ssar ary y 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 Goal:: opti optima mall disp disper ersi sion on for for acti active ve comp compon onen entt and and stab stabililis isat atio ion n agai agains nstt sint sinter erin ing g
How: How: Usin Using g ultr ultra a hard hard and and chem chemic ical ally ly unre unreac activ tive e materials with high melting points (SiO2, TiO2, Al2O3, Carbon….)
With ith a larg large e surfa urface ce area rea (10 (10-? m2/g)
27. April 2005
How big is the SSA of of a si single carbon graphene sh sheet?
Graphite STM Image
~ 2160 kg m-3 Interlaye Interlayerr distance distance = 0.335 0.335 nm ρ
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 nic materia materials ls at large large scale” scale” “anorga
Solid state reactions (precipitation, drying, coagulation)
Reduction, carbonization, leaching
Sol Sol – gel (rea (reacti ctive ve chemi chemistr stry) y)
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) Recati Recative ve gases gases (H2, CH4, NH3…)
ΔT
(500(500- 1500°C 1500°C)) ~ 4-12 4-12 h
Preparation of Catalytic bed (e.g. M, MN x, MCx)
WC, MoC, MoC, W, W, Fe, Fe, CoN CoN …
27. April 2005
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)
27. April 2005
Chemical and Physical Vapor Deposition Atomic Layer Deposition
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Anch Anchor orin ing g and and Gra Graft ftin ing g
Stabl table e coval ovalen entt bond bonds s betw betwee een n homo homoge gene neou ous s tran transi siti tion on meta metall comp comple lex x and and inor inorga gani nic c supp suppor ortt O
O M OH silica
473 K
+
MoCl5
-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
low loading
Support, often porous grains
Dipping Drying, Reduction
calcination T circa 400°C Metal salt solution
Impregnated support
Active Catalyst 27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Precipitation
high loading
Change of T, pH or concentration Metal salt solution
ÆDecrease
solubility of metal
Particle size of active species determined by solubi solubilit lity y + supersol supersolubi ubilit lity y (see (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, 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 phase synthe synthesis sis of nanoma nanomater terial ials s
© Reto Reto Strob Strobel el 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 (e.g YAG 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, 16, 822. W.J. Stark, Commun., 2003, 588-9. 27. April 2005L. Madler, M. Maciejewski, S.E. Pratsinis, and A. Baiker, Chem. Commun.,
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
100
% / d e v o 50 m e r
N2 + H2O
V/TiO2 flame synthesis
x
O N
commercial material 0 100
150
200
250
Process temperature / °C
W. J . Stark, Stark, K. K . Wegne Wegner, S. E. E. Pratsinis, Pratsinis, A. A . Ba Baiker, ker, J J . Cat Catal., 197, 182 (2001) (2001) W. J . Stark, A. A. Baiker, S. E. Pra Prats tsiinis, Part. Part. Sys. Charact. 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
100
90
Peroxid Olefin 1
% / y 80 t i v i t c 70 e l e S 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., Catal., 203, 516 (2001). W. J. Stark, H. K. Kammler, R. Strobel, D. Günther, A. Baiker, S. E. Pratsinis, Ind. Eng. Chem. Res 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 (5)
100
% / 80 e g a s u 60 d i x o r e 40 p
100
O
1
2
OH % / 80
e g a s u 1 n i f e OH l o
Co Cr Mn Fe
60
10
100
1000
(b)
Fe, Ti
TBHP (5 ( 5)
1
O
Lewis acid
40
20
20
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, Stark, R. R. Strobe Strobel. D. Günth Günthe er, S. E. E. Pratsinis, Pratsinis, A. A . Ba Baiker, ker, J J . Mat Mater. Che Chem. 12, 3620 3620 (2002) 27. April 2005
(a)
Ti
6
(d)
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
Pt/alumina: 50 % less Pt required for enantio enantiosel select ective ive hydrog hydrogena enati tions ons flame
100
% / n 75 o i s r e 50 v n o C 25
com commercia cial 0.8 1 -
1000
g
1 -
0.6
m n
75
3
% / 50 e e
E4759 (reference) (reference)
25
5Pt3/3 (this work)
0 0
50
100
time / min
150
200
m0.4 c / ) D 0.2 ( g o l 0 d / V d
1
10
Pore diameter / nm
R. Strobe Strobel, W. J . Stark, L. L . Mä Mädler, S. E. Pra Prats tsiinis, A. A. Ba Baiker, ker, J J . Cat 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 High temper temperatu ature re stabil stability ity cerami ceramic c materi materials als
Ceria/zirconia for for autom utomot otiv ive e exhaust gas cleaning
Compos Composite ite materi materials als Excell Excellent ent cold-s cold-star tartt less less Pt/P Pt/Pd/ d/Rh Rh
27. April 2005
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
0.5 Pt/ceria/zirconia Pt/ceria/zirconia 1 -
g 1.2 k l 1.0 o m0.8 / n e 0.6 g y 0.4 x o 0.2 . n y 0.0 D 0
Flame Wet phase
2 CeO2 CO H2 200
400
600
Ce2O3 + "O" CO2 H2O 800
1000
Temperature / °C 27. April 2005
1200
Refere Reference nce powder powder prep prepar ared ed from from preci precipit pitati ation on and impregnation
Institute of Chemical and Bioengineering ETH Hönggerberg, HCI E 107 8093 Zürich Prof. Dr. Wendelin J. Stark
Catalyst Preparation
0.5 Pt/ceria/zirconia: Thermal stability 1 -
g 1.2 k l 1.0 o m0.8 / n 0.6 e g y 0.4 x o 0.2 . n y 0.0 D 0
200
400
600
Flame, 1
st
Flame, 2
nd
Wet phase, 1
st
Wet phase, 2
nd
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 par particles size strongly influence the sintering stability
Rhod Rhodia ia,, 2004 2004:: frac fracta tall like like stru struct ctur ures es of ceri ceria a base based d oxides:
Highes Highestt therma thermall stabil stability ity..
14 m2/g for for Ce/Z Ce/ZrO rOx afte afterr 1100 1100 °C, °C, 4h
23 m2/g for for Pr-d Pr-dop oped ed Ce/Z Ce/ZrO rOx afte afterr 1100 1100 °C, °C, 4h
Rohart et al, Rhodia Rhodia Electronics Electronics & Catalysis, Top. Catal. 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
Larg Larger er fla flame me spra spray y burn burner ers s
Pilo ilot sca scale le flam flame e spray ray synt sy nthe hesi sis s at 750 750 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
Larg Large e vs. vs. smal smalll star startting powd powder ers s 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 0.5 wt% wt% Pt / CeZr CeZrO O4
Pilot scale,
40-45 m2/g
26-29 m2/g
res. time >30 μsec
0.5 0.5 wt% wt% Pt / CeZ CeZrO rO4
14 m2/g*
Rohart et al, Rhodia Rhodia Electronics Electronics & Catalysis, Top. Catal. 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
Larg Large e vs. vs. smal smalll star startting powd powder ers s
Neck formation, local local equilib equilibriu rium m
Rapid sintering
Rohart et al, Rhodia Rhodia Electronics Electronics & Catalysis, Top. Catal. 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
Larg Large e vs. vs. smal smalll star startting powd powder ers s
Rohart et al, Rhodia Rhodia Electronics Electronics & Catalysis, Top. Catal. 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