New Pt-Pd Coating for Diesel Oxidation Catalyst Dr. Toni Kinnunen Dr. Andreina Moreno Dr. Kauko Kallinen Auli Savimäki Sergio Del Re Osmo Jahkola
New Pt-Pd Coating for Diesel Oxidation Catalyst
Dr. Toni KinnunenDr. Andreina MorenoDr. Kauko KallinenAuli SavimäkiSergio Del ReOsmo Jahkola
Introduction
• Engine and laboratory tests were perfomed to compare Pt-only and Pt-Pd
oxidation catalysts for diesel applications
• Pt-only catalyst: Current Ecocat DOC washcoat
• Pt-Pd catalyst: Next generation Ecocat DOC washcoat
• Catalysts: 90 g/ft3 Pt-only catalyst vs 70 g/ft3 Pt-Pd (4:1) catalyst. Light duty
• Heavy duty studies: 40 g/cft Pt-only vs 30 g/cft Pt-Pd (4:1).
• Same Ecocat® substrate was used for both catalysts in engine tests
Light-Duty studies
Engine TestsLaboratory Tests
Furnace
Catalystin reactor
PreheaterN2
COCO2
NO
Air
C3H6
Heated lines180 °C
Fridge
C3H8Other
FTIR-analyzer
NO/NOx-analyzerCO/CO2-analyzerO2-analyzer
Computer
THC/CH4-analyzer
Heatedsamplingunit
Mas
sfl
ow
con
tro
llers
Syringepump forliquids
Waterpump
Controlcenter
Aftertreatment system: CC+UF
Engine: 1,9 l, 4-cylinder, 74 kWCalibration: Euro IV
EcoCat® Substrate
Fresh engine test results (CC-only LD Euro 4)
0,17
0,493
0,212
0,556
0
0,1
0,2
0,3
0,4
0,5
0,6
THC CO
Em
issi
ons
g/K
m
Current Pt-only, 90 g/cft New Pt-Pd, 4:1, 70 g/cft
Light-Duty studies
Aged (HT800 / 20h) engine test results (CC-only LD Euro 4)
0,237
0,936
0,247
0,852
00,10,20,30,40,50,60,70,80,9
1
THC CO
Em
issi
ons
g/K
m
Current Pt-only, 90 g/cft New Pt-Pd, 4:1, 70 g/cft
Light-Duty studies
Deterioration factors:
1,39
1,9
1,17
1,53
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
2
DF THC DF CODF(
Em
issi
ons
aged
/Em
issi
ons
fres
h)
Current Pt-only, 90g/cft New Pt-Pd, 4:1, 70 g/cft
Light-Duty studies
DF = Emissions agedEmissions fresh
Laboratory EDC simulation –Gas mixture composition
BalanceN2
1000 ppmC3H6
1000 ppmCO
4.5 %CO2
4.5 %H2O
200 ppmNO
12 %O2
ConcentrationComponent
= 2.573
Purpose is to compare the
behavior of Pt vs. Pt-Pd
catalysts with a mixture
containing higher amounts
of CO and THC
Engine calibrations possiblyEngine calibrations possiblyused in future diesel vehiclesused in future diesel vehiclesto reduce emissionsto reduce emissionsNONOXX
Light-Duty studies
Laboratory EDC simulation results –THC fresh
0
20
40
60
80
100
120
0 200 400 600 800 1000 1200
Co
nve
rsio
n(%
)/
Sp
eed
(km
/h)
0
50
100
150
200
250
300
350
Tem
per
atu
re(°
C)
Speed Current 90 g/cft Pt New Pt-Pd 4:1 70 g/cft Temp.
Light-Duty studies
Laboratory EDC simulation results –THC aged (HT800/20h)
0
20
40
60
80
100
120
0 200 400 600 800 1000 1200
Co
nve
rsio
n(%
)/
Sp
eed
(km
/h)
0
50
100
150
200
250
300
350
Tem
per
atu
re(°
C)
Speed Current 90 g/cft Pt New Pt-Pd 4:1 70 g/cft Temp.
Light-Duty studies
Laboratory EDC simulation results –CO aged (HT800/20h)
0
20
40
60
80
100
120
0 200 400 600 800 1000 1200
Con
vers
ion
(%)/
Sp
eed
(km
/h)
0
50
100
150
200
250
300
350
Tem
pera
ture
(°C
)
Speed Current 90 g/cft Pt New Pt-Pd 4:1 70 g/cft Temp.
Light-Duty studies
Light-off Test Results at Different Temperatures
111
139
193 20
5
87
181
184
17718
7 206
211 22
6
173 18
9
189
182
0
50
100
150
200
250
Fresh HT-600°C
HT-700°C
HT-800°C
Fresh HT-600°C
HT-700°C
HT-800°C
Tem
per
atu
re,°
C
CO THCCurrent Pt-only /90 g/cft New Pt-Pd 4:1/ 70 g/cft
Light-Duty studies
Catalyst Characterization: High resolution SEM-EDS
Current Pt-only / HT-800°C/20h aged
New Pt-Pd / Fresh
Current Pt-only / Fresh
New Pt-Pd/ HT-800°C/20h aged
Current Pt-only / HT-800°C/20h aged
New Pt-Pd / Fresh
Current Pt-only / Fresh
New Pt-Pd/ HT-800°C/20h aged
Catalyst Characterization
d=39.835
d=46.402 d=66.846 d=67.775
d=81.500
d=86.051
d=39.835
d=46.402 d=66.846 d=67.775
d=81.500
d=86.051
O
Al
Pd
Pt
O
Al
Pd
Pt
EDS- analysis XRD-analysis
Pt and Pd interact: By forming an alloy
Slows down sintering
Stabilizes Pt
Increases durability
SO2 resistance –Lab EDC simulation with E4 mixture
0,248
0,051
0,256
0,052
0
0,05
0,1
0,15
0,2
0,25
0,3
THC CO
Em
issi
ons
(g/K
m)
Current Pt-only, 90 g/cft New Pt-Pd, 4:1, 70 g/cft
25 ppm SO2HT ageing (400°C / 20h)
Light-Duty studies
PGM price comparison
Price estimate based on PGM prices of 4th quarter 2008 in €
61
40
0
10
20
30
40
50
60
70
Pt only/ 90 g/cft Pt:Pd/ 4:1/ 70 g/cft
Rel
ativ
eP
GM
pri
ces
Heavy Duty Studies
Engine Bench Testing On-Road Ageing
Engine: Calibrated to Euro IIIAgeing cycle: 35000 Km on roadCatalyst: 30 g/cft Pt:Pd (4:1) coatedon EcoCat® substrate
Performance at different test points:- conversion of THC, CO, formation of NO2
Test vehicle:MAN 6.9 l Turbo (D 0826 LOH 17), 166 kW (2400 1/min, 664 Nm)Fuel: city Diesel 8 ppm Sulfur
Bench Engine tests using MAN engine
42 560
289
220
200
1200
Low1
666252384Exhaust gas, m3/h
9800037 00056 500SV, 1/h (6,79 dm3)
440370280Temp., °C
546400207Torque, Nm
215012001800Engine speed, rpm
HighMediumLow2Test point
42 560
289
220
200
1200
Low1
666252384Exhaust gas, m3/h
9800037 00056 500SV, 1/h (6,79 dm3)
440370280Temp., °C
546400207Torque, Nm
215012001800Engine speed, rpm
HighMediumLow2Test point
Heavy Duty Studies
Engine tests - MAN THC conversion
THC conversion as fresh (Average of 2-4 repeats)
0
20
40
60
80
1 00
Co
nv
ers
ion
,%
L o w 1 L o w 2 M e d iu m H ig h
C u rre n t/P t/ 40 g /cft N e w /P t-P d 4 :1 / 30 g /cft
%
Heavy Duty Studies
•THC conversion after 15h (Average of 2-4 repeats)
Engine tests - MAN THC conversion
•THC conversion after 35000 Km On-road ageing (Average of 2-4 repeats)
0
2 0
4 0
6 0
8 0
10 0
Co
nv
ers
ion
,%
L o w 1 L o w 2 M e d iu m H ig h
C u rre n t/P t/ 40 g /c ft N ew /P t-P d 4 :1 / 3 0 g /c ft N ew /P t-P d , 4 :1 /3 0 g /c ft, 3 50 00 K m
%
Heavy Duty Studies
NO2 formation as fresh (Average of 2-4 repeats)
Engine tests - MAN NO2 formation%
0
20
40
60
80
100
Fo
rma
tio
n,
%
L o w 1 L o w 2 M ed iu m H ig h
C u rren t/P t/ 40 g /c ft N e w /P t:P d 4:1 / 3 0 g/c ft
Heavy Duty Studies
NO2 formation after 15 h (Average of 2-4 repeats)
NO2 formation after 35000 Km On-road ageing (Average of 2-4 repeats)
Engine tests - MAN NO2 formation
0102030405060708090
100
Fo
rmat
ion
,%
Low1 Low2 Medium High
Current/Pt/ 40 g/cft New/Pt:Pd 4:1/ 30 g/cft New/Pt-Pd, 4:1/ 30 g/cft, 35000Km
Heavy Duty Studies
Summary
Pt and Pd form an alloy which has different sintering behaviorthan Pt or Pd separately
Pd helps to improve durability by allowing Pt to sinter slowly
Pd helps to keep light-off low after ageing
Combined with proper engine calibrations Pt-Pd catalyst is abetter candidate than classic Pt-only catalysts
NO2 formation decreases indicating its dependence to the Ptloading