Institute of Catalysis and Surface Chemistry

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WP2.2 Advanced Catalyst Development

• Institute of Catalysis and Surface Chemistry
• Polish Academy of Sciences
• 6 months research activities
• new catalyst formulations based on Cu-Mn mixed
  oxides
• synthesis
• physico-chemical characterization
• preliminary catalytic testing

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WP2.2 Advanced Catalyst Development

• Synthetic approach for preparation of mixed oxide
  precursors
• citrate method (sol-gel)
• hydrotalcite method

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WP2.2 Advanced Catalyst Development
Citrate method
Hydrotalcite method
Cu(II), Mn(II), Al(III) nitrates
Cu(II), Mn(II), Al(III) nitrates
2.5 M Citric acid
1 M Na2CO3/NaOH
Viscous solution
Precipitation pH9, 55oC
Stirring 65oC
Drying 50oC
Citrate Gel
Hydrotalcite
Drying 250oC
Calcination 450oC
Xerogel
Mixed oxide
Calcination 550oC
Mixed oxide
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Hydrotalcite (Mg0.75Al0.25)(OH)2(CO3)0.1250.5H2
O
Brucite Mg(OH)2
(Mg0.75Al0.25)(OH)20.25
(CO3)2-0.125
(H2O)0.5
Synthetic hydrotalcite M2(1-x)M3x(OH)2xAn-x/
n?yH2O
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WP2.2 Advanced Catalyst Development
Synthetic hydrotalcite
M2(1-x)M3x(OH)2xAn-x/n
Natural Hydrotalcite M2 Mg2 M3 Al3 An-
CO32-, NO3- x 0.25
Synthetic hydrotalcite M2 Mg, Ni, Zn, Fe, Co,
Cu, MnM3 Al, Mn, Fe, Cr . An - CO32
, NO3-, Cr2O72-, PMo12O403- 0.20ltxlt0.33
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WP2.2 Advanced Catalyst Development
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WP2.2 Advanced Catalyst Development
Thermal decomposition of CuMnAl/111/
hydrotalcite-like precursor monitored in a high
temperature XRD chamber
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WP2.2 Advanced Catalyst Development
Sample Oxidic phases after calcination at Oxidic phases after calcination at Oxidic phases after calcination at Oxidic phases after calcination at Oxidic phases after calcination at Oxidic phases after calcination at Oxidic phases after calcination at Oxidic phases after calcination at Oxidic phases after calcination at
Sample 373 K 473 K 573 K 673 K 773 K 873 K 973 K 1073 K 1173 K
CuAlCO3 (21) HT HT --- --- CuO CuO CuO Cu2Al4O7 CuO Cu2Al4O7 CuO Cu2Al4O7
CuMnAlCO3 (1251) HT R R --- --- CuMn2O4 CuO CuMn2O4 CuO CuMn2O4 CuO CuMn2O4 CuO CuMn2O4 CuO
CuMnAlCO3 (441) HT R R --- --- CuMn2O4 CuO traces Mn2O3 traces CuMn2O4 CuO Mn2O3 Mn2AlO4 CuMn2O4 CuO Mn2AlO4 CuMn2O4 CuO CuMnO2 MnAl2O4
CuMnAlCO3 (211) HT --- --- --- CuMn2O4 CuMn2O4 CuO traces CuMn2O4 MnAl2O4 CuO CuMn2O4 MnAl2O4 CuO CuMn2O4 CuO MnAl2O4
CuMnAlCO3 (111) HT R R --- --- CuMn2O4 CuMn2O4 (weak) Mn1xAl2-xO4 CuMn2O4 Mn2AlO4 MnAl2O4 CuMn2O4 CuO Mn2AlO4 CuMn2O4 CuO Mn2AlO4
CuMnAlCO3 (121) HT R R --- --- CuMn2O4 CuMn2O4 Mn2O3 CuMn2O4 Mn2O3 Mn2AlO4 CuMn2O4 Mn2O3 traces Mn2AlO4 CuMn2O4
MnAlCO3 (21) HT R --- --- --- Mn3O4 Mn3O4 Mn3O4 Mn2AlO4 Mn2O3 Mn2AlO4
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WP2.2 Advanced Catalyst Development
XRD of mixed oxides derived from
hydrotalcite-like precursors
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WP2.2 Advanced Catalyst Development

• Bulk vs. surface chemical composition

Sample CuMnAl atomic ratios-bulk values (ICP OES) CuMnAl atomic ratios-surface values (XPS) BET m2/g
CuMnAl (1251) 135.11 4.72.11 55
CuMnAl (441) 4.14.21 0.91.61 61
CuMnAl (111) 1.11.21 1.21.81 96
CuMnAl (211) 2.11.11 1.20.61 62
CuMnAl (121) 1.12.21 0.911 132
MnAl (21) 2.31 0.41 237
CuAl (21) 2.21 0.21 30
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WP2.2 Advanced Catalyst Development
Transmission Electron Microscopy
HAADF STEM
CuMnAl (111)
HAADF STEM shows that CuMnAl (111) is a mixture
of semi-amorphous oxide phases of different
composition. HRTEM proves that one of them is
nanocrystalline spinel CuMn2O4.
HRTEM
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WP2.2 Advanced Catalyst Development
Scanning Electron Microscopy
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WP2.2 Advanced Catalyst Development
XPS
Contribution of various Cu and Mn oxidation
states at the surface of a CuMnAl/211/Ht
catalyst after exposure to air at different
temperatures
Sample Cu Cu2 Mn2 Mn4
CuMn 1350C 5.1 42.65 31.5 68.5
CuMn 2400C 61.2 35.5 27.5 72.5
reduction
oxidation
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WP2.2 Advanced Catalyst Development
H2 TPR of Cu-Mn-Al mixed oxides derived from
hydrotalcite precursors
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WP2.2 Advanced Catalyst Development
XRD patterns of Cu-Mn-Al mixed oxides derived
from citrate precursors.
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WP2.2 Advanced Catalyst Development
Influence of the nature of precursor
MnAl/21/Ht
MnAl/21/Cit
237 m2/g
77 m2/g
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WP2.2 Advanced Catalyst Development
CH4 combustion fixed-bed flow glass reactor, p1
bar, temperature 175-525oC, catalyst - 0.5 ml,
CH4 1g/m3, GHSV 10 000 h-1.
Sample T50 oC BET m2/g
CuMnAl/441/Ht 389 61
CuMnAl/121/Ht 411 132
MnAl/21/Ht 412 237
CuAl/21/Ht 470 30
MnAl/21/Cit 478 77
MnAl/12/Cit 439 324
Cu/Mn/12/Cit 458 18
ECOCAT washcoat 255 n.d.
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WP2.2 Advanced Catalyst Development

• Future action
• Further exploration along the compositions based
  on mixed Cu and Mn oxides, aiming at maximization
  of the specific surface area and simultaneous
  formation of the copper-rich spinel phase.
• Investigation of compositions enriched with
  promoters (e.g. Ce, Zr).
• Synthesis of perovskite and hexaaluminate
  precursors containing Co and La.