Materials for Hydrogen Production, Conversion, and Storage

Inamuddin, PhD, is an assistant professor in the Department of Applied Chemistry, Aligarh Muslim University, Aligarh, India. He has extensive research experience in analytical chemistry, materials chemistry, electrochemistry, renewable energy, and environmental science. He has worked on different research projects funded by various government agencies and universities and is the recipient of multiple awards, including the Fast Track Young Scientist Award and the Young Researcher of the Year Award for 2020, from Aligarh Muslim University. He has published almost 200 research articles in various international scientific journals, 19 book chapters, and 145 edited books with multiple well-known publishers, including Scrivener Publishing. He is a member of various editorial boards for scientific and technical journals and is an editor on several of them in different capacities. Tariq Altalhi, PhD, is an assistant professor and department head in the Department of Chemistry at Taif University, Saudi Arabia. He is also the Vice Dean of the College of Science, and he leads a group involved in fundamental interdisciplinary research across numerous fields. Sayed Mohammed Adnan, PhD, is a research scholar in the Department of Chemical Engineering, Aligarh Muslim University, India. He is actively involved in research and has published several articles in reputed journals. His research areas are very broad, encompassing a multitude of scientific areas. Mohammed A. Amin, PhD, is a professor of physical chemistry at Taif University, Saudi Arabia, and a professor of physical chemistry at Ain Shams University, Cairo, Egypt. He has won numerous scholarly awards and has been a guest editor for a reputable scientific journal.

• Preface xxi1 Transition Metal Oxides in Solar-to-Hydrogen Conversion 1Zuzanna Bielan and Katarzyna Siuzdak1.1 Introduction 21.2 Solar-to-Hydrogen Conversion Processes Utilizing Transition Metal Oxides 31.2.1 Photocatalysis 31.2.2 Photoelectrocatalysis 51.2.3 Thermochemical Water Splitting 61.3 Transition Metal Oxides in Solar-to-Hydrogen Conversion Processes 71.3.1 Photocatalysis and Photoelectrocatalysis 71.3.1.1 TiO 2 81.3.1.2 α-Fe 2 O 3 161.3.1.3 CuO/Cu 2 O 201.3.2 Thermochemical Water Splitting 231.3.2.1 Fe 3 O 4 /FeO Redox Pair 241.3.2.2 CeO 2 /Ce 2 O 3 and CeO/CeO 2-δ Redox Pairs 251.3.2.3 ZnO/Zn Redox Pair 271.4 Conclusions and Future Perspectives 28References 292 Catalytic Conversion Involving Hydrogen from Lignin 41Satabdi Misra and Atul Kumar VarmaList of Abbreviations 412.1 Introduction 422.1.1 Background of Bio-Refinery and Lignin 422.1.2 Lignin as an Alternate Source of Energy 442.1.3 Lignin Isolation Process 452.2 Catalytic Conversion of Lignin 452.2.1 Lignin Reductive Depolymerization into Aromatic Monomers 472.2.2 Catalytic Hydrodeoxydation (HDO) of Lignin 482.2.3 Hydrodeoxydation (HDO) of Lignin-Derived-Bio-Oil 51Summary and Outlook 52References 533 Solar–Hydrogen Coupling Hybrid Systems for Green Energy 65Bilge Coşkuner Filiz, Esra Balkanli Unlu, Hülya Civelek Yörüklü, Meltem Karaismailoglu Elibol, Yağmur Akar, Ali Turgay San, Halit Eren Figen and Aysel Kantürk Figen3.1 Concept of Green Sources and Green Storage 663.2 Coupling of Green to Green 673.3 Solar Energy–Hydrogen System 673.3.1 Photoelectrochemical Hydrogen Production 683.3.1.1 PEC Materials 703.3.1.2 Photoelectrochemical Systems 733.3.2 Electrochemical Hydrogen Production 743.3.2.1 Polymer Electrolyte Membrane Electrolysis Cell (PEMEC) 753.3.2.2 Alkaline Electrolysis Cell (AEC) 763.3.2.3 Solid Oxide Electrolysis Cell (SOEC) 773.3.3 Fuel Cell 783.3.4 Photovoltaic 793.4 Thermochemical Systems 803.5 Photobiological Hydrogen Production 823.6 Conclusion 84References 854 Green Sources to Green Storage on Solar–Hydrogen Coupling 97A. Mohan Kumar, R. Rajasekar, P. Sathish Kumar, S. Santhosh and B. Premkumar4.1 Introduction 984.1.1 Hybrid System 994.2 Concentrated Solar Thermal H 2 Production 1014.3 Thermochemical Aqua Splitting Technology for Solar–H 2 Generation 1034.4 Solar to Hydrogen Through Decarbonization of Fossil Fuels 1054.4.1 Solar Cracking 1064.5 Solar Thermal-Based Hydrogen Generation Through Electrolysis 1074.6 Photovoltaics-Based Hydrogen Production 1074.7 Conclusion 109References 1105 Electrocatalysts for Hydrogen Evolution Reaction 115R. Shilpa, K. S. Sibi, S. R. Sarath Kumar, R. K. Pai and R.B. Rakhi5.1 Introduction 1165.2 Parameters to Evaluate Efficient HER Catalysts 1175.2.1 Overpotential (o.p) 1175.2.2 Tafel Plot 1185.2.3 Stability 1195.2.4 Faradaic Efficiency and Turnover Frequency 1195.2.5 Hydrogen Bonding Energy (HBE) 1205.3 Categories of HER Catalysts 1215.3.1 Noble Metal-Based Catalysts 1215.3.2 Non-Noble Metal-Based Catalysts 1255.3.3 Metal-Free 2D Nanomaterials 1265.3.4 Transition Metal Dichalcogenides 1295.3.5 Transition Metal Oxides and Hydroxides 1305.3.6 Transition Metal Phosphides 1325.3.7 MXenes (Transition Metal Carbides and Nitrides) 132Conclusion 134References 1346 Recent Progress on Metal Catalysts for Electrochemical Hydrogen Evolution 147Tejaswi Jella and Ravi Arukula6.1 Introduction 1486.1.1 Type of Water Electrolysis Technologies 1486.1.1.1 Alkaline Electrolysis (AE) 1496.1.1.2 Proton Exchange Membrane Electrolysis (peme) 1496.1.1.3 Solid Oxide Electrolysis (SOE) 1496.2 Mechanism of Hydrogen Evolution Reaction (HER) 1496.2.1 Performance Evaluation of Catalyst 1516.3 Various Electrocatalysts for Hydrogen Evolution Reaction (her) 1536.3.1 Noble Metal Catalysts for HER 1536.3.1.1 Platinum-Based Catalysts 1536.3.1.2 Palladium Based Catalysts 1556.3.1.3 Ruthenium Based Catalysts 1576.3.2 Non-Noble Metal Catalysts 1586.3.2.1 Transition Metal Phosphides (TMP) 1586.3.2.2 Transition Metal Chalcogenides 1626.3.2.3 Transition Metal Carbides (TMC) 1636.4 Conclusion and Future Aspects 164References 1657 Dark Fermentation and Principal Routes to Produce Hydrogen 181Luana C. Grangeiro, Bruna S. de Mello, Brenda C. G. Rodrigues, Caroline Varella Rodrigues, Danieli Fernanda Canaver Marin, Romario Pereira de Carvalho Junior, Lorena Oliveira Pires, Sandra Imaculada Maintinguer, Arnaldo Sarti and Kelly J. Dussán7.1 Introduction 1827.2 Biohydrogen Production from Organic Waste 1837.2.1 Crude Glycerol 1867.2.1.1 Dark Fermentation of Crude Glycerol to Biohydrogen and Bio Products 1877.2.2 Dairy Waste 1897.2.2.1 Dark Fermentation of Dairy Waste to Biohydrogen and Bioproducts 1907.2.3 Fruit Waste 1937.2.3.1 Dark Fermentation of Fruit Waste to Hydrogen and Bioproducts 1947.3 Anaerobic Systems 1987.3.1 Continuous Multiple Tube Reactor 2067.4 Conclusion and Future Perspectives 209Acknowledgements 210References 2108 Catalysts for Electrochemical Water Splitting for Hydrogen Production 225Zaib Ullah Khan, Mabkhoot Alsaiari, Muhammad Ashfaq Ahmed, Nawshad Muhammad, Muhammad Tariq, Abdur Rahim and Abdul Niaz8.1 Introduction 2268.2 Water Splitting and Their Products 2298.3 Different Methods Used for Water Splitting 2298.3.1 Setup for Water Splitting Systems at a Basic Level 2298.3.2 Photocatalysis 2308.3.3 Electrolysis 2328.4 Principles of PEC and Photocatalytic H 2 Generation 2328.5 Electrochemical Process for Water Splitting Application 2338.5.1 Water Splitting Through Electrochemistry 2338.6 Different Materials Used in Water Splitting 2338.6.1 Water Oxidation (OER) Materials 2338.6.2 Developing Materials for Hydrogen Synthesis 2358.6.3 Material Stability for Water Splitting 2358.7 Mechanism of Electrochemical Catalysis in Water Splitting and Hydrogen Production 2358.7.1 Electrochemical Water Splitting with Cheap Metal-Based Catalysts 2368.7.2 Catalysts with Only One Atom 2368.7.3 Electrochemical Water Splitting Using Low-Cost Metal-Free Catalysts 2378.8 Water Splitting and Hydrogen Production Materials Used in Electrochemical Catalysis 2388.8.1 Metal and Alloys 2388.8.2 Metal Oxides/Hydroxides and Chalogenides 2398.8.3 Metal Carbides, Borides, Nitrides, and Phosphides 2398.9 Uses of Hydrogen Produced from Water Splitting 2408.9.1 Water Splitting Generates Hydrogen Energy 2408.9.2 Photoelectrochemical (PEC) Water Splitting 2418.9.3 Thermochemical Water Splitting 2418.9.4 Biological Water Splitting 2418.9.5 Fermentation 2418.9.6 Biomass and Waste Conversions 2428.9.7 Solar Thermal Water Splitting 2428.9.8 Renewable Electrolysis 2428.9.9 Hydrogen Dispenser Hose Reliability 2428.10 Conclusion 243References 2439 Challenges and Mitigation Strategies Related to Biohydrogen Production 249Mohd Nur Ikhmal Salehmin, Ibdal Satar and Mohamad Azuwa Mohamed9.1 Introduction 2499.2 Limitation and Mitigation Approaches of Biohydrogen Production 2529.2.1 Physical Issues and Their Mitigation Approaches 2529.2.1.1 Operating Temperature Issue and Its Control 2529.2.1.2 Hydraulic Retention Time (HRT) and Optimization 2529.2.1.3 High Hydrogen Partial Pressure – Implication and Overcoming the Issue 2539.2.1.4 Membrane Fouling Issues and Solutions 2549.2.2 Biological Issues and Their Mitigation Approaches 2569.2.2.1 Start-Up Issue and Improvement Through Bioaugmentation 2569.2.2.2 Biomass Washout Issue and Solution Through Cell Immobilization 2569.2.3 Chemical Issues and Their Mitigation Approaches 2579.2.3.1 pH Variation and Its Regulation 2579.2.3.2 Limiting Nutrient Loading and Optimization 2579.2.3.3 Inhibitor Secretion and Its Control 2589.2.3.4 Byproduct Formation and Its Exploitation 2609.2.4 Economic Issues and Ways to Optimize Cost 2609.3 Conclusion and Future Direction 265Acknowledgements 266References 26610 Continuous Production of Clean Hydrogen from Wastewater by Microbial Usage 277P. Satishkumar, Arun M. Isloor and Ramin Farnood10.1 Introduction 27810.2 Wastewater for Biohydrogen Production 27910.3 Photofermentation 28110.3.1 Continuous Photofermentation 28310.3.2 Factors Affecting Photofermentation Hydrogen Production 28610.3.2.1 Inoculum Condition and Substrate Concentration 28610.3.2.2 Carbon and Nitrogen Source 28710.3.2.3 Temperature 28810.3.2.4 pH 28810.3.2.5 Light Intensity 28810.3.2.6 Immobilization 29010.4 Dark Fermentation 29110.4.1 Continuous Dark Fermentation 29210.4.2 Factors Affecting Hydrogen Production in Continuous Dark Fermentation 29610.4.2.1 Start-Up Time 29610.4.2.2 Organic Loading Rate 29610.4.2.3 Hydraulic Retention Time 29710.4.2.4 Temperature 30110.4.2.5 pH 30210.4.2.6 Immobilization 30210.5 Microbial Electrolysis Cell 30410.5.1 Mechanism of Microbial Electrolysis Cell 30410.5.2 Wastewater Treatment and Hydrogen Production 30510.5.3 Factors Affecting Microbial Electrolysis Cell Performance 30810.5.3.1 Inoculum 30810.5.3.2 pH 30810.5.3.3 Temperature 30810.5.3.4 Hydraulic Retention Time 30810.5.3.5 Applied Voltage 31010.6 Conclusions 310References 31111 Conversion Techniques for Hydrogen Production and Recovery Using Membrane Separation 319Nor Azureen Mohamad Nor, Nur Shamimie Nadzwin Hasnan, Nurul Atikah Nordin, Nornastasha Azida Anuar, Muhamad Firdaus Abdul Sukur and Mohamad Azuwa Mohamed11.1 Introduction 32011.2 Conversion Technique for Hydrogen Production 32111.2.1 Photocatalytic Hydrogen Generation via Particulate System 32111.2.2 Photoelectrochemical Cell (PEC) 32411.2.3 Photovoltaic-Photoelectrochemical Cell (PV-PEC) 32511.2.4 Electrolysis 32711.3 Hydrogen Recovery Using Membrane Separation (h 2 /o 2 Membrane Separation) 32911.3.1 Polymeric Membranes 33011.3.2 Porous Membranes 33111.3.3 Dense Metal Membranes 33211.3.4 Ion-Conductive Membranes 33311.4 Conclusion 335Acknowledgements 336References 33612 Geothermal Energy-Driven Hydrogen Production Systems 343Santanu Ghosh and Atul Kumar VarmaAbbreviations 34412.1 Introduction 34512.2 Hydrogen – A Green Fuel and an Energy Carrier 34712.3 Production of Hydrogen 34812.3.1 Fossil Fuel-Based 34812.3.2 Non-Fossil Fuel-Based 34912.4 Geothermal Energy 35312.4.1 Introductory View 35312.4.2 Types and Occurrences 35412.5 Hydrogen Production From Geothermal Energy 35512.5.1 Hydrogen Production Systems 35512.5.2 Working Fluids 36912.5.3 Assimilation of Solar and Geothermal Energy 37012.5.4 Chlor-Alkali Cell and Abatement of Mercury and Hydrogen Sulfide (AMIS) Unit 37212.5.5 Hydrogen Liquefaction 37412.5.6 Hydrogen Storage 37512.6 Economics of Hydrogen Production 37712.6.1 A General Overview 37712.6.2 Economy of Hydrogen Yield Using Geothermal Energy 37912.7 Environmental Impressions of Geothermal Energy-Driven Hydrogen Yield 38112.8 Conclusions 382References 38413 Heterogeneous Photocatalysis by Graphitic Carbon Nitride for Effective Hydrogen Production 397Kiran Kumar B., B. Venkateswar Rao, Sashivinay Kumar Gaddam, Ravi Arukula and Vishnu Shanker13.1 Introduction 39813.1.1 Typical Heterogeneous Photocatalysis Mechanism 39913.1.2 Necessity of the Photocatalytic Water Splitting 40013.2 g-C 3 N 4 -Based Photocatalytic Water Splitting 40113.2.1 Influence of the g-C 3 N 4 Morphology on Photocatalytic Water Splitting 40213.2.1a g-C 3 N 4 Thin Nanosheets-Based Photocatalytic Water Splitting 40213.2.1b Porous g-C 3 N 4 -Based Photocatalytic Water Splitting 40413.2.1c Crystalline g-C 3 N 4 -Based Photocatalytic Water Splitting 40513.2.2 Metal Doped Photocatalytic Water Splitting 40613.2.3 Semiconductor/g-C 3 N 4 Heterojunction for Photocatalytic Water Splitting 40713.3 Future Remarks and Conclusion 408References 40914 Graphitic Carbon Nitride (g-CN) for Sustainable Hydrogen Production 417Zaib Ullah Khan, Mabkhoot Alsaiari, Saleh Alsayari, Nawshad Muhmmad and Abdur Rahim14.1 Introduction 41814.2 Various Methods for Hydrogen Production 42114.3 Production of Hydrogen from Fossil Fuels 42214.3.1 Steam Reforming 42214.3.2 Gasification 42214.4 Hydrogen Production from Nuclear Energy 42214.4.1 Water Splitting by Thermochemistry 42214.5 Hydrogen Production from Renewable Energies 42314.5.1 Electrolysis 42314.5.2 Photovoltaic Solar 42314.5.3 Wind Method for Producing Hydrogen 42314.5.4 Biomass Gasification Use for Hydrogen Production 42414.5.5 Agricultural or Food-Processing Waste that Contains Starch and Cellulose 42414.6 Preparation of g-C 3 N 4 Materials 42514.6.1 Sol-Gel Method for Making Graphitic Carbon Nitride 42614.6.2 Hard and Soft-Template Method 42614.6.3 Template-Free Method for Making Graphitic Carbon Nitride 42814.7 Properties of g-C 3 N 4 Materials 42914.7.1 Stability 42914.7.1.1 Thermal Stability 42914.7.1.2 Chemical Stability 43014.7.1.3 Electrochemical Properties 43014.8 The Advantages of Sustainable Hydrogen Production and Their Applications 43014.8.1 Hydrogen Applications 43014.9 Hydro Processing in Petroleum Refineries and Their Usage 43114.9.1 Hydrocracking 43114.9.2 Hydrofining 43114.9.3 Ammonia Synthesis 43214.9.4 Synthesis of Methanol 43314.9.5 Electricity Generation from Hydrogen 43314.9.6 Applications for Green Hydrogen 43414.9.7 Replacing Existing Hydrogen 43414.9.8 Heating 43514.9.9 Energy Storage 43514.9.10 Alternative Fuels 43514.9.11 Fuel-Cell Vehicles 43614.10 Conclusion 436References 43615 Hydrogen Production from Anaerobic Digestion 441Muhammad Farhan Hil Me, Mohd Nur Ikhmal Salehmin, Hau Seung Jeremy Wong and Mohamad Azuwa Mohamed15.1 Introduction 44115.2 Basic Overview of Anaerobic Digestion 44315.3 How to Obtain Hydrogen from Anaerobic Digestion 44515.3.1 Single-Stage Reactor 44515.3.2 Two-Stage Reactor 44515.3.3 Feedstock and Resulting Hydrogen 44615.4 Challenges and Mitigation Strategies in Biohydrogen Production 44715.4.1 Combating Microbial Competition 44715.4.2 Enhancing Biohydrogen Production Yield by Technical and Operational Adjustments 44815.4.3 Minimizing Inhibition by Byproducts from Pretreatments 45015.4.4 Minimizing Inhibition by Metal Ions 45115.4.5 Minimizing In-Process Inhibition 45215.4.5.1 Volatile Fatty Acids and Alcohols 45215.4.5.2 Ammonia 45315.4.5.3 Hydrogen 45315.5 Practicality of Technologies at Industrial Scale 45315.6 Conclusion 456Acknowledgements 456References 45616 Impact of Treatment Strategies on Biohydrogen Production from Waste-Activated Sludge Fermentation 465Rajeswari M. Kulkarni, Dhanyashree J.K., Esha Varma, Sirivibha S.P. and Shantha M.P.16.1 Introduction 46616.2 Methods of Production of Hydrogen Using WAS 46716.2.1 Dark Fermentation 46816.2.2 Photofermentation 46916.2.3 Microbial Electrolysis Cell 47016.3 Physical Treatment Methods 47116.4 Chemical Treatment Methods 48616.5 Conclusions 504References 50517 Microbial Production of Biohydrogen (BioH 2) from Waste-Activated Sludge: Processes, Challenges, and Future Approaches 511Abhispa Bora, T. Angelin Swetha, K. Mohanrasu, G. Sivaprakash, P. Balaji and A. Arun17.1 Introduction 51217.2 Hydrogen and Waste-Activated Sludge 51317.2.1 Hydrogen 51317.2.2 Waste-Activated Sludge 51417.3 Mechanisms of Hydrogen Production 51417.3.1 H 2 Production by Dark Fermentation Process 51517.3.2 H 2 Production by Photofermentation Process 51617.3.3 Using Microbial Electrolysis Cell 51817.4 H 2 Production by Microalgae Using Waste 52017.4.1 Bottlenecks of H 2 Production 52017.4.2 Key Factors Influencing H 2 Production 52117.5 Recent Endeavors to Enhance H 2 Production 52217.5.1 Recent Advancements in Dark Fermentation 52217.5.2 Recent Advances in Photofermentation 52617.5.3 Recent Advances in Microbial Electrolysis Cell 52717.6 Future Approaches 52817.7 Conclusion 528References 52918 Perovskite Materials for Hydrogen Production 539Surawut Chuangchote and Kamonchanok Roongraung18.1 Current Problems of Technology for Hydrogen Production 54018.2 Principle of Perovskite Materials 54018.2.1 Oxide Perovskite 54218.2.1.1 Titanate-Based Oxide Perovskite (ATiO 3) 54218.2.1.2 Tantalate-Based Oxide Perovskite (ATaO 3) 54418.2.1.3 Niobate-Based Oxide Perovskite 54518.2.2 Halide Perovskite 54718.2.2.1 Conventional Halide Perovskite 54718.2.2.2 Lead-Free Halide Perovskites 54818.3 Synthesis Process for Perovskite Materials 54918.3.1 Microwaves 55018.3.2 Sol-Gel 55018.3.3 Hydrothermal/Solvothermal 55118.3.4 Precipitation 55318.3.5 Hot-Injection 55318.4 Hydrogen Production from Solar Water Splitting 55418.4.1 Photocatalytic System 55518.4.2 Photoelectrochemical System 55618.4.3 Photovoltaic–Electrocatalytic System 55918.5 Conclusion and Future Perspectives 562References 56319 Progress on Ni-Based as Co-Catalysts for Water Splitting 575Arti Maurya, Kartick Chandra Majhi and Mahendra Yadav19.1 Introduction 57619.1.1 Thermodynamic Aspects of Hydrogen Production 57719.1.2 Different Processes for the Photocatalytic Hydrogen Evolution by Water Splitting 57819.1.3 Photocatalyst 57819.1.3.1 Homogeneous Photocatalysis 57819.1.3.2 Heterogeneous Photocatalysis 57919.2 Photocatalytic Hydrogen Generation System 58119.2.1 Electron Donor and Electrolyte/Sacrificial Reagent 58119.2.2 Loading of Co-Catalyst 58119.2.3 Photocatalytic Activity Efficiency 58319.3 Semiconductor Materials 58419.3.1 Oxide-Based Semiconductor and Their Composites 58419.3.2 Non-Oxide-Based Semiconductor and Their Composites 58619.3.3 Polymer/Carbon Dots/Graphene-Based and Carbon Nitride-Based Photocatalyst and Their Composites 58819.4 State of Art for the Nickel Used as Photocatalyst 59119.5 Progress of Ni-Based Photocatalyst for Hydrogen Evolution 59219.5.1 Metallic Form of Ni Used as Co-Catalyst 59219.5.2 Ni-Based Oxide and Hydroxide Used as Co-Catalyst for Hydrogen Production 59419.5.3 Ni-Based Sulfides Used as Co-Catalyst and Photocatalyst 59619.5.4 Ni-Based Phosphides Used as Co-Catalyst Towards Hydrogen Production 59819.5.5 Ni-Based Complex Act as Co-Catalyst for Hydrogen Production 60019.5.6 Other Ni-Based Co-Catalyst for Hydrogen Production 60219.6 Conclusion and Future Perspective 608Author Declaration 609Acknowledgment 609References 60920 Use of Waste-Activated Sludge for the Production of Hydrogen 625Hülya Civelek Yörüklü, Bilge Coşkuner Filiz and Aysel Kantürk Figen20.1 Introduction 62620.2 WAS to Hydrogen Production 62920.2.1 Biohydrogen Production 62920.2.1.1 Dark Fermentation 62920.2.1.2 Photofermentation 63220.2.1.3 Microbial Electrolysis Cell 63420.2.2 Thermochemical Hydrogen Production 63520.2.2.1 Pyrolysis 63620.2.2.2 Gasification 63920.2.2.3 Super Critical Water Gasification 64320.3 Conclusion Remarks 645References 64621 Current Trends in the Potential Use of the Metal-Organic Framework for Hydrogen Storage 655Maryam Yousaf, Muhammad Ahmad, Zhi-Ping Zhao, Tehmeena Ishaq and Nasir Mahmood21.1 Introduction 65621.2 Structure of MOFs 65721.3 Mechanism of H 2 Storage by MOFs 65921.4 Strategies to Modify the Structure of MOFs for Enhanced H 2 Storage 66121.4.1 Tuning the Surface Area, Pore Size, and Volume of MOFs 66121.4.2 Enhancement in Unsaturated Open Metal Sites 66321.4.3 MOFs with Interpenetration 66521.4.4 Linker Functionalization of MOFs 66721.4.5 Hybrid and Doping of MOFs 66821.5 Conclusions and Future Recommendations 674Acknowledgement 675References 67522 High-Density Solids as Hydrogen Storage Materials 681Zeeshan Abid, Huma Naeem, Faiza Wahad, Sughra Gulzar, Tabassum Shahzad, Munazza Shahid, Muhammad Altaf and Raja Shahid Ashraf22.1 Introduction 68222.2 Metal Borohydrides 68322.2.1 Lithium Borohydride 68322.2.2 Sodium Borohydride 68522.2.3 Potassium Borohydride 68722.3 Metal Alanates 68822.3.1 Lithium Alanate 68822.3.2 Sodium Alanate 69022.4 Ammonia Boranes 69122.5 Metal Amides 69322.5.1 Lithium Amide 69322.5.2 Sodium Amide 69422.6 Amine Metal Borohydrides 69622.6.1 Amine Lithium Borohydrides 69622.6.2 Amine Magnesium Borohydrides 69722.6.3 Amine Calcium Borohydrides 69822.6.4 Amine Aluminium Borohydrides 69922.7 Conclusion 699References 699Index 707