Nanostructured Materials for Next-Generation Energy Storage and Conversion (eBook)

Dr. Bashir was chair of the American Chemical Society (ACS) South Texas Region (2011–2012); Dr. Liu was secretary/treasurer of the same section (2010–2011). Part of their leadership role was to invite elite speakers from top universities to come to the south Texas region to give technical presentations.In 2012–2013, both Drs. Bashir and Liu co-organized a symposium on behalf of the National ACS Conference (COLLOIDAL division) in Indianapolis, IN, related to colloidal based bottom-up synthesis in nanofabrication related to environmental and energy aspects. At that conference, Dr. Liu separately co-organized energy talks on behalf of the ACS ENERGY division.In March 2014, both Drs. Bashir and Liu co-organized an ACS symposium (COLLOIDAL division) in Dallas, TX, related to environmental cleanup using nano-engineered systems.Both editors are therefore well known and well connected in this field to put forth an excellent book on this topic.

Preface 5
The Carbon Economy: Current Dilemma 6
Acknowledgment 9
Author Contributions 9
References 9
Contents 11
List of Contributors 12
1 Photocatalytic Hydrogen Evolution 20
1.1 Introduction 21
1.2 Fundamental Mechanisms 24
1.3 Semiconductor Photocatalysts 29
1.4 d0 Metal Oxide Photocatalyst 30
1.4.1 Group 4 Elements (Ti, Zr)-Based Oxides 30
1.4.2 Group 5 Elements (Nb, Ta)-Based Oxides 31
1.4.3 Group 6 Elements (W, Mo) and Other d0 Elements-Based Oxides 33
1.4.4 d10 Metal Oxide Photocatalyst 33
1.4.5 f0 Metal Oxide Photocatalyst 34
1.4.6 Nonmetal Oxide Photocatalyst 34
1.5 Approaches to Modify Electronic Band Structure 36
1.5.1 Doping 36
1.5.2 Metal Ion Doping 36
1.5.3 Nonmetal Doping 37
1.5.4 Solid Solutions 37
1.5.5 Dye Sensitization 38
1.5.6 Cocatalyst Loading 38
1.5.6.1 Noble Metal Cocatalyst 38
1.5.6.2 Nontransition-Metal Cocatalyst 39
1.6 Nanostructure of Semiconductors 40
1.6.1 0-D Material 40
1.6.2 1-D Material 41
1.6.3 2-D Material 42
1.7 Sacrificial Reagents 44
1.8 Overall Water Splitting 45
1.9 Perovskite-Structure Photocatalyst 46
1.10 Perovskite Solar Cell 48
1.11 Summary and Future Prospects 52
References 53
2 Transition Metal Complexes for Hydrogen Activation 61
2.1 Introduction and Background 62
2.2 Molecular Complexes for Hydrogen Activation 67
2.2.1 Hydrogen Activation by Mononuclear Transition Metal Complexes 67
2.2.1.1 Homolytic Cleavage of H2 67
2.2.1.2 Heterolytic Cleavage of H2 69
2.2.1.3 Transition Metal Complex as Homogenous Hydrogenation Catalysts 71
2.2.2 Heterometallic Cluster Complexes for Hydrogen Activation 76
2.2.2.1 Heterometallic Cluster Complexes for Hydrogen Activation and Homogenous Hydrogenation Catalysis 76
2.2.2.2 Biomimetic Model Complexes for Hydrogen Activation 81
2.3 Supported Nanoclusters for Hydrogenation Reactions 85
2.3.1 Transition Metal Cluster Complexes as Precursors for Heterogeneous Hydrogenation 87
2.3.2 Heavy Main Group Metal Modified Transition Metal Clusters as Supported Catalysts for Hydrogenation 92
2.4 Summary 95
References 96
3 Hydrogen Separation Membranes of Polymeric Materials 103
3.1 Overview of Hydrogen Separation Membrane Technology 105
3.2 Principles of Hydrogen Separation Membrane 108
3.2.1 Gas Separation Mechanism 108
3.2.2 Gas Separation Mechanism for Polymer Membrane 110
3.2.3 Gas Separation Performance Evaluation 111
3.3 Polymer Materials and Membrane Structure 113
3.3.1 Polymeric Membrane Material for Hydrogen Separation 114
3.3.1.1 Polyimide (PI) 115
3.3.1.2 Polybenzimidazole (PBI) 116
3.3.2 Hydrogen Separation Membrane Structure 119
3.3.2.1 Dense Membrane 119
3.3.2.2 Porous Membrane 120
3.3.2.3 Hybrid Microporous Membrane 120
Mixed Matrix Membrane 120
Polymer Intrinsic Microporosity 121
3.4 Industrial Application of Hydrogen Separation Polymer Membrane 121
3.4.1 Current Industrial Development 123
3.4.2 Membrane Fabrication Technique 125
3.4.3 Modules and System Configuration 126
3.5 Summary and Next Generation Hydrogen Separation Membrane 128
References 130
4 Hydrogen Storage Technologies 135
4.1 Hydrogen as a Fuel 136
4.1.1 Introduction 136
4.1.2 Hydrogen Economy 137
4.2 Hydrogen Storage 139
4.2.1 Classification of Hydrogen Storage Technologies 139
4.2.2 US Department of Energy Targets for Hydrogen Storage Systems for Light Duty Vehicles 140
4.2.3 Current Status of Hydrogen Storage Technologies 141
4.3 Hydrogen Storage Technologies 141
4.3.1 Physical Methods of Hydrogen Storage 141
4.3.1.1 Compressed Gaseous Hydrogen Storage 141
4.3.1.2 Liquefied Hydrogen Storage 144
4.3.1.3 Cryo-Compressed Hydrogen Storage 146
4.3.2 Chemical Methods of Hydrogen Storage 147
4.3.2.1 Solid-State Hydrogen Storage (On-board Regenerable Materials) 147
Reversible Hydrides 148
Metal Hydrides 148
Complex Hydrides 149
Porous Materials 149
4.3.2.2 Chemical Hydrogen Storage (Off-board Regenerable Materials) 150
Sodium Borohydride 150
Aluminum Hydride 151
Ammonia-Borane 151
Liquid Organic Hydrogen Carriers 152
4.3.3 Hybrid Methods of Hydrogen Storage 152
4.3.3.1 Cryo-Adsorption Hydrogen Storage 152
4.4 Challenges of Hydrogen Storage Technologies 153
4.5 Summary 154
References 156
5 Hydrogen Storage in Metal-Organic Frameworks 161
5.1 Introduction 162
5.2 Syntax Used for Hydrogen Storage 164
5.2.1 Adsorption or Absorption 164
5.2.2 Chemisorption and Physisorption 164
5.2.3 Langmuir Surface Area and BET Surface Area 165
5.2.4 Excess and Total Adsorption Amount of Hydrogen 167
5.2.5 Isosteric Heat of the Hydrogen Adsorption 168
5.3 Engineering Novel MOFs for Hydrogen Storage 168
5.3.1 MOFs Based on Carboxylate Linkers 169
5.3.2 MOFs Based on Azolate Linkers 173
5.3.3 MOFs Based on Mixed Linkers 175
5.4 Postsynthetic Modification of MOFs to Improve the Hydrogen Storage Capability 177
5.4.1 Postmodification of the Inorganic Clusters 179
5.4.2 Postmodification of the Organic Linkers 180
5.4.3 Post Modification of MOFs by Doping Catalysts 183
5.5 Summary 184
References 184
6 Porous Carbons for Hydrogen Storage 189
6.1 Introduction 191
6.2 Adsorptive Hydrogen Storage 191
6.2.1 The Chahine Rule 191
6.2.2 Deliverable (or Working) Capacity 193
6.2.3 BET Surface Area 193
6.3 Porous Carbons with High Hydrogen Uptake 195
6.3.1 Activated Carbons 195
6.3.2 Porous Graphene-Based Materials 197
6.3.3 MOF-Derived Porous Carbons 201
6.3.4 Doped Porous Carbons 206
6.3.5 Zeolite-Templated Carbons 210
6.3.6 Carbide-Derived Carbons 214
6.3.7 Porous Polymer Networks 215
6.4 Summary 217
References 217
7 Strategies for Hydrogen Storage in Porous Organic Polymers 221
7.1 Introduction 222
7.2 Key Challenges for Porous Materials in Hydrogen Storage 224
7.2.1 Surface Area 225
7.2.2 Pore Size Distribution 226
7.2.3 Heat of Adsorption 227
7.3 Advantages of POPs Over MOFs 228
7.3.1 Potential to Reach Higher Surface Area 228
7.3.2 Excellent Physicochemical Stability 229
7.4 Strategies to Improve Hydrogen Storage Capacity in POPs 230
7.4.1 Rational Design to Achieve High Surface Area 230
7.4.1.1 Size of Monomer 230
7.4.1.2 Geometry of Monomer 231
7.4.1.3 Efficiency of Polymerization 231
7.4.2 Improving Heat of Adsorption by Metal Insertion 232
7.4.3 Capacity Improvement Through Material Engineering 234
7.5 Summary 236
References 237
8 Metal Hydrides used for Hydrogen Storage 242
8.1 Metal Hydrides Fundamentals 243
8.2 Classification of the Hydrides 244
8.2.1 Ionic Hydrides 245
8.2.2 Covalent Hydrides 245
8.2.3 Metallic Hydrides 245
8.3 Metal Hydride Formation 245
8.4 Metal Hydride properties 246
8.4.1 Pressure-Composition-Temperature (PCT) 246
8.4.2 Activation and Decrepitation 248
8.4.3 Kinetics of Hydriding and Dehydriding 249
8.4.4 Gaseous Impurity Resistance 249
8.4.5 Cyclic Stability, Alloy Cost, and Safety 250
8.5 Metal Hydride Families 250
8.5.1 Elements 251
8.5.2 Alloys 251
8.5.3 AB5 Intermetallic Compounds 251
8.5.4 AB2 Intermetallic Compounds 252
8.5.5 AB Intermetallic Compounds 252
8.5.6 A2B Intermetallic Compounds 253
8.5.7 Other Intermetallic Compounds 253
8.5.8 Mg-Based Hydrides 254
8.6 Metal Hydrides Synthesis and Characterization Equipment 255
8.6.1 Synthesis Techniques 256
8.6.1.1 High Energy Ball Mill (BM) 256
8.6.1.2 Nitrogen Filled Glove Box (Dry Box) 257
8.6.1.3 Solvent Purification System 258
8.6.1.4 Annealing (Tube Furnace) System 258
8.6.2 Characterization Techniques 259
8.6.2.1 Differential Scanning Calorimetry (DSC) 259
8.6.2.2 Thermogravimetric Analysis (TGA) 260
8.6.2.3 X-Ray Diffractrometer (XRD) 261
8.6.2.4 Scanning Electron Microscope (SEM) 262
8.6.2.5 Energy Dispersive X-Ray Spectroscopy (EDS) 263
8.6.2.6 Pressure Composition Temperature (PCT) Apparatus 264
8.6.2.7 Thermal Programmed Desorption or Reaction (TPD/TPR) 265
8.6.2.8 Fourier Transform Infrared Spectrometer (FT-IR) 266
8.6.2.9 Gas Chromatography and Mass Spectroscopy (GC-MS) 267
8.7 Summary 268
References 269
9 Characterization of H2 Adsorption Sites: Where Are the Hydrogens Stored in the Materials? 273
9.1 Characterization of Material-H2 Interactions 274
9.2 Neutron Powder Diffraction 275
9.2.1 Comparison Between Neutron and X-ray Diffraction 275
9.2.2 Hydrogen/Deuterium Adsorption Sites in Crystalline Materials 277
9.2.3 Observation of Hydrogen/Deuterium Interlinked Clusters 281
9.3 Inelastic Neutron Scattering 282
9.3.1 Introduction to Inelastic Neutron Scattering 282
9.3.2 Hydrogen/Deuterium Filling Orders and Binding Energy 285
9.3.3 Minute Difference in Binding Sites in Reticular Structures 287
9.4 Infrared Spectroscopy 289
9.4.1 IR Response to Free and Trapped Hydrogen Molecules 289
9.4.2 Indirect Structural Information and Selected Reference 290
9.5 Solid-State Nuclear Magnetic Resonance 291
9.5.1 Hydrogen/Deuterium Bound to Transition Metal Clusters 292
9.5.2 Probe of para- and ortho-Hydrogen 295
9.6 Strategies Inspired from the Characterizations to Increase H2 Uptake 297
9.6.1 Increase in Surface Area and Tailoring Pore Geometry 298
9.6.1.1 Ligand Elongation 298
9.6.1.2 Catenation and Interpenetration 298
9.6.1.3 Impregnation 300
9.6.1.4 Mixed Ligand System 300
9.6.2 Increase in Isosteric Heat of H2 Adsorption 301
9.6.2.1 Exposed Metal Sites 301
9.6.2.2 Ionic Frameworks and Functionalization 301
9.7 Summary 302
References 303
10 Hydrogen-driven Economy and Utilization 307
10.1 Introduction of Hydrogen Economy 309
10.2 Properties of Hydrogen 316
10.2.1 Covalent Diatomic Molecule 316
10.3 Generation of Hydrogen 317
10.3.1 Generation of Hydrogen from Water 320
10.3.2 Steam Methane Reformation Coupled with CO2 Sequestration 323
10.3.3 Generation of Hydrogen from Methane 324
10.3.4 Generation of Hydrogen from Microorganism 325
10.4 Utilization of Hydrogen in Fuel Cells 325
10.4.1 Use of Hydrogen in Proton Exchange Membrane Fuel Cells 328
10.4.2 Use of Hydrogen in Solid Oxide Fuel Cells 329
10.4.3 Use of Hydrogen in Fuel Cell Vehicle 333
10.4.4 Hydrogen Storage for Transport 338
10.5 Renewable Framework, Path, and Policy 338
10.5.1 Environmental Remediation 340
10.5.2 Biomass for Electrical Generation 341
10.5.3 Biogas for Electrical or Hydrogen Generation 341
10.5.4 Sulfur-Iodine Thermocycle for Hydrogen Generation 342
10.5.5 The Hydrogen Production, Storage, and Utilization 342
10.6 Hydrogen Economy from 2015 to 2050 343
10.6.1 Hydrogen Distribution and Economics 344
10.7 Conclusion: Realistic Expectations for Hydrogen as Energy Carrier: For Our Yesterdays, Today and Tomorrows 345
References 346
Conclusion 356
Index 357