Your text hHeterogeneous Catalysis: Fundamentals,
Engineering and Characterizations (with accompanying
presentation slides and instructor's manual)ere 1
Contents
Preface.................................................................................................................. ix
Chapter 1: Introduction .......................................................................................... 1
1.1 Historical background ............................................................................................ 1
1.2 Fundamental concepts and quantities in catalysis .................................................. 7
1.2.1 Fractional coverage .....................................................................................7
1.2.2 Catalytic activity .........................................................................................7
1.2.3 Conversion, yield, and selectivity .............................................................11
1.3 Importance of heterogeneous catalysis in today’s industry ................................... 17
1.3.1 Ammonia synthesis ...................................................................................18
1.3.2 Sulfuric acid production ............................................................................19
1.3.3 Catalytic cracking .....................................................................................20
1.3.4 Polymerization of alpha-olefins ................................................................21
1.4 Questions and problems ....................................................................................... 22
References ................................................................................................................... 23
Chapter 2: Fundamentals of the adsorption process ............................................... 27
2.1 Physical and chemical adsorption ........................................................................ 27
2.2 Thermodynamics and energetics of adsorption .................................................... 36
2.2.1 Heat of adsorption.....................................................................................37
2.2.2 Binding energy of adsorbates ....................................................................39
2.3 Kinetics of adsorption .......................................................................................... 42
2.3.1 Adsorption time ........................................................................................42
2.3.2 Adsorption rate .........................................................................................44
2.3.3 Potential energy diagrams .........................................................................47
2.3.4 The Elovich equation in chemisorption kinetics ........................................54
2.3.5 Desorption rate .........................................................................................56
2.4 Questions and problems ....................................................................................... 59
References ................................................................................................................... 60
v
,vi Contents
Chapter 3: Adsorption models, surface reaction, and catalyst architectures ............. 63
3.1 Adsorption isotherms and their classification ....................................................... 63
3.1.1 Langmuir isotherm ....................................................................................68
3.1.2 Henry’s isotherm.......................................................................................70
3.1.3 Freundlich isotherm ..................................................................................71
3.1.4 Temkin isotherm .......................................................................................72
3.1.5 BET isotherm............................................................................................72
3.1.6 Potential theory of Polanyi ........................................................................75
3.1.7 Recent approaches to model adsorption isotherms ....................................77
3.2 Adsorption isobars and isosteres .......................................................................... 79
3.3 Models for surface reactions ................................................................................ 81
3.4 Catalysts, cocatalysts, and supports...................................................................... 86
3.4.1 Catalyst supports .......................................................................................87
3.4.2 Cocatalysts ................................................................................................92
3.5 Questions and problems ....................................................................................... 95
References ................................................................................................................... 97
Chapter 4: Surface area and porosity ...................................................................101
4.1 Estimation of the surface area ............................................................................ 101
4.1.1 Gravimetric and dynamic methods ..........................................................102
4.1.2 Volumetric methods ................................................................................104
4.2 Estimation of porosity and pore size .................................................................. 108
4.2.1 Dubinin Radushkevich and Dubinin Astakhov methods ......................110
4.2.2 Horvath Kawazoe method .....................................................................110
4.2.3 Saito Foley method ...............................................................................112
4.2.4 Barrett Joyner Halenda method ...........................................................113
4.2.5 Dollimore Heal method .........................................................................114
4.2.6 Density functional theory ........................................................................115
4.2.7 Mercury porosimetry...............................................................................116
4.3 Hysteresis and capillary condensation ................................................................ 117
4.4 Pore models—morphology................................................................................. 123
4.5 Mechanisms of diffusion within catalyst pores .................................................. 128
4.6 Questions and problems ..................................................................................... 135
References ................................................................................................................. 138
Chapter 5: Catalytic reaction engineering .............................................................141
5.1 Catalytic reaction steps ...................................................................................... 141
5.1.1 External diffusion ...................................................................................142
, Contents vii
5.1.2 Internal diffusion.....................................................................................144
5.1.3 Adsorption ..............................................................................................144
5.1.4 Surface reaction ......................................................................................147
5.1.5 Desorption ..............................................................................................149
5.2 Reaction mechanism and the rate-limiting step .................................................. 149
5.3 Catalytic reactor design ..................................................................................... 155
5.4 Diffusion and reaction in heterogeneous catalysis .............................................. 162
5.4.1 Mass transfer-limited and reaction rate-limited reactions ........................162
5.4.2 Diffusion with reaction in a catalyst pellet ..............................................164
5.4.3 Thiele modulus .......................................................................................168
5.4.4 Internal and overall effectiveness factors ................................................170
5.4.5 Weisz Prater and the Mears criteria ......................................................175
5.5 Multiple steady states and thermal hysteresis ..................................................... 176
5.6 Catalyst deactivation and regeneration ............................................................... 179
5.7 Questions and problems ..................................................................................... 187
References ................................................................................................................. 191
Chapter 6: Green heterogeneous catalysis ............................................................193
6.1 Conversion of biomass to biofuels ..................................................................... 194
6.1.1 Biomass feedstock ..................................................................................194
6.1.2 Traditional thermochemical processes for catalytic conversion of
biomass ...................................................................................................197
6.1.3 Aqueous-phase reforming for hydrogen and alkanes production .............202
6.2 Electrocatalysis .................................................................................................. 205
6.2.1 Fundamentals of electrocatalytic processes .............................................205
6.2.2 Water electrolysis ...................................................................................209
6.2.3 Electrochemical CO2 reduction ...............................................................214
6.3 Photocatalysis .................................................................................................... 218
6.3.1 Fundamentals of photocatalytic processes ...............................................218
6.3.2 Water and wastewater purification ..........................................................224
6.3.3 Organic synthesis ....................................................................................230
6.4 Questions and problems ..................................................................................... 234
References ................................................................................................................. 237
Chapter 7: Characterization techniques ................................................................243
7.1 X-ray diffraction .............................................................................................. 243
7.2 X-ray photoelectron spectroscopy .................................................................... 250
7.3 X-ray absorption spectroscopy ......................................................................... 254
7.4 Electron microscopy ........................................................................................ 259
, viii Contents
7.5 Infrared and Raman spectroscopy .................................................................... 266
7.6 Temperature-programed methods ..................................................................... 272
7.7 Electrochemical techniques .............................................................................. 277
7.7.1 Voltammetry ......................................................................................... 279
7.7.2 Electrochemical impedance spectroscopy.............................................. 283
7.8 UV visible and photoluminescence spectroscopy ........................................... 286
7.8.1 UV visible spectroscopy...................................................................... 286
7.8.2 Photoluminescence spectroscopy .......................................................... 290
7.9 Solid-state nuclear magnetic resonance and electron paramagnetic
resonance spectroscopies.................................................................................. 293
7.9.1 Nuclear magnetic resonance.................................................................. 293
7.9.2 Electron paramagnetic resonance .......................................................... 296
7.10 Computational tools: density functional theory and molecular
dynamic simulations ........................................................................................ 301
7.11 Questions and problems ................................................................................... 305
References ................................................................................................................. 309
Index ..................................................................................................................315
Engineering and Characterizations (with accompanying
presentation slides and instructor's manual)ere 1
Contents
Preface.................................................................................................................. ix
Chapter 1: Introduction .......................................................................................... 1
1.1 Historical background ............................................................................................ 1
1.2 Fundamental concepts and quantities in catalysis .................................................. 7
1.2.1 Fractional coverage .....................................................................................7
1.2.2 Catalytic activity .........................................................................................7
1.2.3 Conversion, yield, and selectivity .............................................................11
1.3 Importance of heterogeneous catalysis in today’s industry ................................... 17
1.3.1 Ammonia synthesis ...................................................................................18
1.3.2 Sulfuric acid production ............................................................................19
1.3.3 Catalytic cracking .....................................................................................20
1.3.4 Polymerization of alpha-olefins ................................................................21
1.4 Questions and problems ....................................................................................... 22
References ................................................................................................................... 23
Chapter 2: Fundamentals of the adsorption process ............................................... 27
2.1 Physical and chemical adsorption ........................................................................ 27
2.2 Thermodynamics and energetics of adsorption .................................................... 36
2.2.1 Heat of adsorption.....................................................................................37
2.2.2 Binding energy of adsorbates ....................................................................39
2.3 Kinetics of adsorption .......................................................................................... 42
2.3.1 Adsorption time ........................................................................................42
2.3.2 Adsorption rate .........................................................................................44
2.3.3 Potential energy diagrams .........................................................................47
2.3.4 The Elovich equation in chemisorption kinetics ........................................54
2.3.5 Desorption rate .........................................................................................56
2.4 Questions and problems ....................................................................................... 59
References ................................................................................................................... 60
v
,vi Contents
Chapter 3: Adsorption models, surface reaction, and catalyst architectures ............. 63
3.1 Adsorption isotherms and their classification ....................................................... 63
3.1.1 Langmuir isotherm ....................................................................................68
3.1.2 Henry’s isotherm.......................................................................................70
3.1.3 Freundlich isotherm ..................................................................................71
3.1.4 Temkin isotherm .......................................................................................72
3.1.5 BET isotherm............................................................................................72
3.1.6 Potential theory of Polanyi ........................................................................75
3.1.7 Recent approaches to model adsorption isotherms ....................................77
3.2 Adsorption isobars and isosteres .......................................................................... 79
3.3 Models for surface reactions ................................................................................ 81
3.4 Catalysts, cocatalysts, and supports...................................................................... 86
3.4.1 Catalyst supports .......................................................................................87
3.4.2 Cocatalysts ................................................................................................92
3.5 Questions and problems ....................................................................................... 95
References ................................................................................................................... 97
Chapter 4: Surface area and porosity ...................................................................101
4.1 Estimation of the surface area ............................................................................ 101
4.1.1 Gravimetric and dynamic methods ..........................................................102
4.1.2 Volumetric methods ................................................................................104
4.2 Estimation of porosity and pore size .................................................................. 108
4.2.1 Dubinin Radushkevich and Dubinin Astakhov methods ......................110
4.2.2 Horvath Kawazoe method .....................................................................110
4.2.3 Saito Foley method ...............................................................................112
4.2.4 Barrett Joyner Halenda method ...........................................................113
4.2.5 Dollimore Heal method .........................................................................114
4.2.6 Density functional theory ........................................................................115
4.2.7 Mercury porosimetry...............................................................................116
4.3 Hysteresis and capillary condensation ................................................................ 117
4.4 Pore models—morphology................................................................................. 123
4.5 Mechanisms of diffusion within catalyst pores .................................................. 128
4.6 Questions and problems ..................................................................................... 135
References ................................................................................................................. 138
Chapter 5: Catalytic reaction engineering .............................................................141
5.1 Catalytic reaction steps ...................................................................................... 141
5.1.1 External diffusion ...................................................................................142
, Contents vii
5.1.2 Internal diffusion.....................................................................................144
5.1.3 Adsorption ..............................................................................................144
5.1.4 Surface reaction ......................................................................................147
5.1.5 Desorption ..............................................................................................149
5.2 Reaction mechanism and the rate-limiting step .................................................. 149
5.3 Catalytic reactor design ..................................................................................... 155
5.4 Diffusion and reaction in heterogeneous catalysis .............................................. 162
5.4.1 Mass transfer-limited and reaction rate-limited reactions ........................162
5.4.2 Diffusion with reaction in a catalyst pellet ..............................................164
5.4.3 Thiele modulus .......................................................................................168
5.4.4 Internal and overall effectiveness factors ................................................170
5.4.5 Weisz Prater and the Mears criteria ......................................................175
5.5 Multiple steady states and thermal hysteresis ..................................................... 176
5.6 Catalyst deactivation and regeneration ............................................................... 179
5.7 Questions and problems ..................................................................................... 187
References ................................................................................................................. 191
Chapter 6: Green heterogeneous catalysis ............................................................193
6.1 Conversion of biomass to biofuels ..................................................................... 194
6.1.1 Biomass feedstock ..................................................................................194
6.1.2 Traditional thermochemical processes for catalytic conversion of
biomass ...................................................................................................197
6.1.3 Aqueous-phase reforming for hydrogen and alkanes production .............202
6.2 Electrocatalysis .................................................................................................. 205
6.2.1 Fundamentals of electrocatalytic processes .............................................205
6.2.2 Water electrolysis ...................................................................................209
6.2.3 Electrochemical CO2 reduction ...............................................................214
6.3 Photocatalysis .................................................................................................... 218
6.3.1 Fundamentals of photocatalytic processes ...............................................218
6.3.2 Water and wastewater purification ..........................................................224
6.3.3 Organic synthesis ....................................................................................230
6.4 Questions and problems ..................................................................................... 234
References ................................................................................................................. 237
Chapter 7: Characterization techniques ................................................................243
7.1 X-ray diffraction .............................................................................................. 243
7.2 X-ray photoelectron spectroscopy .................................................................... 250
7.3 X-ray absorption spectroscopy ......................................................................... 254
7.4 Electron microscopy ........................................................................................ 259
, viii Contents
7.5 Infrared and Raman spectroscopy .................................................................... 266
7.6 Temperature-programed methods ..................................................................... 272
7.7 Electrochemical techniques .............................................................................. 277
7.7.1 Voltammetry ......................................................................................... 279
7.7.2 Electrochemical impedance spectroscopy.............................................. 283
7.8 UV visible and photoluminescence spectroscopy ........................................... 286
7.8.1 UV visible spectroscopy...................................................................... 286
7.8.2 Photoluminescence spectroscopy .......................................................... 290
7.9 Solid-state nuclear magnetic resonance and electron paramagnetic
resonance spectroscopies.................................................................................. 293
7.9.1 Nuclear magnetic resonance.................................................................. 293
7.9.2 Electron paramagnetic resonance .......................................................... 296
7.10 Computational tools: density functional theory and molecular
dynamic simulations ........................................................................................ 301
7.11 Questions and problems ................................................................................... 305
References ................................................................................................................. 309
Index ..................................................................................................................315
