539
3.1 Synthesis of Catalyst: Importance of Aerosol Routes
Heterogeneous catalysts may be broadly divided into bulk catalysts and supported
catalysts. Bulk catalysts consist mainly of the active catalytic material (inert binders
may be added to aid the forming processes) while supported catalysts consists of
active catalytic materials dispersed on the surface of a support material. Table 3
shows bulk and supported catalysts used in industry.
Table 2 CO 2 Reforming reactions
S/N
Reaction
∆H 298
a (kJ/mole)
Description
1
CH 4 + CO 2 = 2CO + 2H 2
+247
Dry reforming
2
CH 4 + H 2 O = CO + 3H 2
+206
Steam reforming
3
CH 4 + ½ O 2 = CO + 2H 2
−36
Partial oxidation
4
CH 4 + 2O 2 = CO 2 + 2H 2 O
−880
Methane combustion
5
CO 2 + H 2 = CO + H 2 O
+41.1
Reverse water gas shift
6
CH 4 = C + 2H 2
+75
Methane cracking
7
2CO = C + CO 2
−172.4
Boudouard reaction
8
C + H 2 O = CO + H 2
+131.3
Water gas reaction
9
C + O 2 = CO 2
−393.5
Coke combustion
a
∆H 298 is the heat of reaction at 298 K
Table 3 Bulk and supported catalyst used in the industry
Industrial processes
Bulk catalyst
Al 2 O 3
Claus process, dehydration of alcohols to olefins and
ethers
Al 2 O 3 /SiO 2
Fluid catalytic cracking, acid-catalyzed reactions
Fe-Molybdate
Selective oxidation (methanol to formaldehyde)
Bi-Molybdate
Selective oxidation (propene to acrolein)
Vanadyl pyrophosphate
Selective oxidation (butane to maleic anhydride)
Fe 2 O 3 -Cr 2 O 3
High temperature water gas shift
Supported catalyst
Cu/ZnO-Al 2 O 3
Methanol synthesis
Ag/α-Al 2 O 3
Selective oxidation (ethylene to ethylene oxide)
Pt-Re/Al 2 O 3
Catalytic naphtha reforming
Cr 2 O 3 /Al 2 O 3
Toulene dehydroalkylation
Pt/Al 2 O 3
Propane dehydrogenation
Ni/Al 2 O 3
Steam methane reforming
Synthesis of Novel Catalysts for Carbon Dioxide Conversion to Products of Value
3.1 Synthesis of Catalyst: Importance of Aerosol Routes
Heterogeneous catalysts may be broadly divided into bulk catalysts and supported
catalysts. Bulk catalysts consist mainly of the active catalytic material (inert binders
may be added to aid the forming processes) while supported catalysts consists of
active catalytic materials dispersed on the surface of a support material. Table 3
shows bulk and supported catalysts used in industry.
Table 2 CO 2 Reforming reactions
S/N
Reaction
∆H 298
a (kJ/mole)
Description
1
CH 4 + CO 2 = 2CO + 2H 2
+247
Dry reforming
2
CH 4 + H 2 O = CO + 3H 2
+206
Steam reforming
3
CH 4 + ½ O 2 = CO + 2H 2
−36
Partial oxidation
4
CH 4 + 2O 2 = CO 2 + 2H 2 O
−880
Methane combustion
5
CO 2 + H 2 = CO + H 2 O
+41.1
Reverse water gas shift
6
CH 4 = C + 2H 2
+75
Methane cracking
7
2CO = C + CO 2
−172.4
Boudouard reaction
8
C + H 2 O = CO + H 2
+131.3
Water gas reaction
9
C + O 2 = CO 2
−393.5
Coke combustion
a
∆H 298 is the heat of reaction at 298 K
Table 3 Bulk and supported catalyst used in the industry
Industrial processes
Bulk catalyst
Al 2 O 3
Claus process, dehydration of alcohols to olefins and
ethers
Al 2 O 3 /SiO 2
Fluid catalytic cracking, acid-catalyzed reactions
Fe-Molybdate
Selective oxidation (methanol to formaldehyde)
Bi-Molybdate
Selective oxidation (propene to acrolein)
Vanadyl pyrophosphate
Selective oxidation (butane to maleic anhydride)
Fe 2 O 3 -Cr 2 O 3
High temperature water gas shift
Supported catalyst
Cu/ZnO-Al 2 O 3
Methanol synthesis
Ag/α-Al 2 O 3
Selective oxidation (ethylene to ethylene oxide)
Pt-Re/Al 2 O 3
Catalytic naphtha reforming
Cr 2 O 3 /Al 2 O 3
Toulene dehydroalkylation
Pt/Al 2 O 3
Propane dehydrogenation
Ni/Al 2 O 3
Steam methane reforming
Synthesis of Novel Catalysts for Carbon Dioxide Conversion to Products of Value