reading

Cover page

Title page
Copyright page
Preface
Acknowledgments
1: Introduction to Basic Properties of Hydrogen
1. 1.1 Basics about THE Hydrogen Element
2. 1.2 Basics about the Hydrogen Molecule
3. 1.3 Other Fundamental Aspects of Hydrogen
4. 1.4 Safety and Precautions about Hydrogen
5. References
2: Hydrocarbons for Hydrogen Generation
1. 2.1 Basics about Hydrocarbons
2. 2.2 Steam Methane Reforming
3. 2.3 Partial Oxidation
4. 2.4 Methanol and Ethanol Steam Reforming
5. 2.5 Glycerol Reforming
6. 2.6 Cracking of Ammonia and Methane
7. 2.7 Summary
8. References
3: Solar Hydrogen Generation: Photocatalytic and Photoelectrochemical Methods
1. 3.1 Basics about Solar Water Splitting
2. 3.2 Photocatalyic Methods
3. 3.3 Photoelectrochemical Methods
4. 3.4 Summary
5. References
4: Biohydrogen Generation and Other Methods
1. 4.1 Basics about Biohydrogen
2. 4.2 Pathways of Biohydrogen Production from Biomass
3. 4.3 Thermochemical Conversion of Biomass to Hydrogen
4. 4.4 Biological Process for Hydrogen Production
5. 4.5 Summary
6. References
5: Established Methods Based on Compression and Cryogenics
1. 5.1 Basic Issues about Hydrogen Storage
2. 5.2 High Pressure Compression
3. 5.3 Liquid Hydrogen
4. 5.4 Summary
5. References
6: Chemical Storage Based on Metal Hydrides and Hydrocarbons
1. 6.1 Basics on Hydrogen Storage of Metal Hydrides
2. 6.2 Hydrogen Storage Characteristics of Metal Hydrides
3. 6.3 Different Metal Hydrides
4. 6.4 Hydrocarbons for Hydrogen Storage
5. 6.5 Summary
6. References
7: Physical Storage Using Nanostructured and Porous Materials
1. 7.1 Physical Storage Using Nanostructures
2. 7.2 Physical Storage Using Metal-Organic Frameworks
3. 7.3 Clathrate Hydrates
4. 7.4 Summary
5. References
8: Hydrogen Utilization: Combustion
1. 8.1 Basics about Combustion
2. 8.2 Mechanism of Combustion
3. 8.3 Major Factors Affecting Combustion
4. 8.4 Catalytic Combustion
5. 8.5 Summary
6. References
9: Hydrogen Utilization: Fuel Cells
1. 9.1 Basics of Fuel Cells
2. 9.2 Types of Fuel Cells
3. 9.3 Catalysts for Oxygen Reduction Reaction of Fuel Cells
4. 9.4 Fuel Processing
5. 9.5 Applications of Fuel Cells
6. 9.6 Summary
7. References
10: Hydrogen Utilization in Chemical Processes
1. 10.1 Background
2. 10.2 Hydrogen Utilization in Petroleum Industry
3. 10.3 Hydrogen Utilization in Chemical Industry
4. 10.4 Hydrogen Utilization in Metallurgical Industry
5. 10.5 Hydrogen Utilization in Manufacturing Processes
6. 10.6 Hydrogen Utilization in Physics
7. 10.7 Summary
8. References
Supplemental Images
Index
End User License Agreement

List of Tables

TABLE 4.1 Comparison of Hydrogen Yields Are Obtained by Use of Three Different Processes
TABLE 4.2 Hydrogen Production from Conversion of Oil Palm Shell and Physic Nut Waste
TABLE 4.3 Product Distribution Obtained from Different Processes of Pyrolysis Process
TABLE 4.4 Typical Gas Composition Data as Obtained from Commercial Wood and Charcoal Downdraft Gasifiers Operated on Low to Medium Moisture Content Fuels (Wood 20%, Charcoal 7%)
TABLE 4.5 Composition of Bio-Syngas from Biomass Gasification
TABLE 4.6 Comparison of Hydrogen Yields Are Obtained by Use of Three Different Processes
TABLE 4.7 The Main Advantages of Different Biological Hydrogen Production Processes
TABLE 4.8 Classification of Hydrogenases
TABLE 5.1 Hydrogen Compressibility Factor (Z) at 20°C and Corresponding Volumetric Capacity $c5-math-5011$ [4]
TABLE 8.1 Summary of 19 Reversible Elementary Reactions in the H₂O₂ Reaction Mechanism
TABLE 8.2 Summary of Several Important Reactions Involving NO_x in Hydrogen Combustion
TABLE 9.1 The Different Fuel Cells that Have Been Realized and Their Electrode Reactions

List of Illustrations

FIGURE 1.1 Relevant energy level of the ground electronic state of the H atom and its ionized state (H⁺ + e). E is energy, n is the principal quantum number, r is the distance between the electron and proton; −(1/r) is the Coulombic attraction between the electron and proton; and 13.6 eV corresponds to the ionization energy of the H atom from its ground electronic state (n = 1 or 1s atomic orbital).
FIGURE 1.2 Examples of several low-lying PES of H₂. Source: Reproduced with permission from Flemming et al. [4].
FIGURE 2.1 Schematic of the thermal swing sorption-enhanced reaction (TSSER)-steam-methane reforming (SMR) concept. Source: Reproduced with permission of Beaver et al. [2].
FIGURE 2.2 Schematic of a compact, tubular, small-scale methane reformer designed for fuel cell applications with convective heat transfer. Source: Reproduced with permission from Ogden [1].
FIGURE 2.3 Comparison of the steam reforming and partial oxidation methods. Source: Reproduced with permission from Ogden [1].
FIGURE 2.4 Selectivities of ethanol reforming as a function of temperature (H2O/EtOH = 3.7). Source: Reproduced with permission from Fierro et al. [9].
FIGURE 2.5 Dependence of selectivity of product gases on the flow rate of ethanol. Source: Reproduced with permission from Wang et al. [10].
FIGURE 2.6 Hydrogen selectivity and glycerol conversion over (a) Ni/Al₂O₃ and (b) Rh/CeO₂/Al₂O₃ for 13 hours at 900°C, with a feed flow rate of 0.15 mL min⁻¹ and water to glycerol ratio of 6. Source: Reproduced with permission from Adhikari et al. [14].
FIGURE 2.7 Chemical equilibrium of 2NH₃ = N₂ + 3 H₂ as a function of temperature and pressure. Source: Reproduced with permission from Hacker and Kordesch [15].
FIGURE 2.8 Different options for generating and purifying ammonia synthesis gas. Source: Reproduced with permission from Appl [16].
FIGURE 2.9 Equilibrium composition and conversion as a function of temperature. The figure shows the equilibrium number of moles based on an initial 100 mol of CH₄. Source: Reproduced with permission from Amin et al. [17].
FIGURE 2.10 Proposed mechanism of reaction. Source: Reproduced from Wang et al. [21].
FIGURE 3.1 (a) Photocatalytic hydrogen generation rate collected for ZnO nanorod arrays (NRA) film, hydrogen-treated ZnO (H:ZnO) NRA film, and H:ZnO nanorod (NR) powder in a solution containing 0.1 M Na₂SO₃ and 0.1 M Na₂S under white light irradiation. (b) Cycling performance of H : ZnO NRA films. Source: Reproduced with permission from Lu et al. [24]. (See color insert.)
FIGURE 3.2 (a–b) TEM images of GaP nanowires. The inset in (a) shows the indexed FFT pattern of the image, indicating the wire is a single crystal with a growth axis of [111] direction. (c) Photograph of a large GaP nanowire membrane on a PVDF filter membrane. Source: Reproduced with permission from Sun et al. [18]. (See color insert.)
FIGURE 3.3 (a,b) TEM images of graphene sheet decorated with CdS clusters. Inset: SAED pattern collected at the composite structure. (c) Schematic illustration of the charge separation and transfer in the graphene-CdS system under visible light. (d) Comparison of the visible light photocatalytic activity of graphene–CdS systems with different graphene loading for the H₂ production using 10 vol% lactic acid aqueous solution as a sacrificial reagent and 0.5 wt% Pt as a co-catalyst. Source: Reproduced with permission from Li et al. [30]. (See color insert.)
FIGURE 3.4 Schematic energy diagram of PEC water splitting with (a) photoanode, (b) photocathode, and (c) n-type photoanode and p-type photocathode. Source: Reproduced with permission from Liu et al. [31]. (See color insert.)
FIGURE 3.5 (a) Schematic presentation of the electrode structure. (b) Scanning electron micrograph showing a top view of the electrode after ALD of 5 × (4 nm ZnO/0.17 nm Al₂O₃)/11 nm TiO₂ followed by electrodeposition of Pt nanoparticles. (c) Current-potential characteristics in 1 M Na₂SO₄ solution under chopped AM 1.5 light illumination for the bare Cu₂O electrode, (d) for the as-deposited 5 × (4 nm ZnO/0.17 nm Al₂O₃)/11 nm TiO₂. The insets show respective photocurrent transient for the electrodes held at 0 V versus RHE in chopped light illumination with N₂ purging. Source: Reproduced with permission from Paracchino et al. [32]. (See color insert.)
FIGURE 3.6 (a) SEM image of silicon nanowire arrays fabricated by metal-catalyzed chemical etching; inset is the photograph of ∼10 mm × 10 mm silicon nanowire array sample with low reflection. (b) Schematic of silicon nanowire arrayed photoelectrode. Photon absorbed by silicon nanowire generates minority carrier, which drifts to semiconductor/electrolyte interface where H⁺ is reduced to H₂. Silicon nanowires are impregnated with Pt nanoparticles that serve as electrocatalysts for water reduction. (c) PEC performance of bare silicon nanowire and planar silicon film. (d) PEC performance of Pt modified planar silicon and nanowire silicon. Source: Reproduced with permission from Oh et al. [36]. (See color insert.)
FIGURE 3.7 (a) Linear sweep voltammograms collected on pristine TiO₂nanowire and hydrogen-treated TiO₂ (H:TiO₂) nanowires annealed at temperature of 350, 400, and 450°C. (b) IPCE spectra of pristine TiO₂ and H:TiO₂ nanowires. The inset is the magnified IPCE spectra that highlighted in the dashed box. (c) Simulated solar-to-hydrogen efficiencies for the pristine TiO₂and H : TiO₂ samples as a function of wavelength, by integrating their IPCE spectra collected at −0.6 V versus Ag/AgCl with a standard AM 1.5G solar spectrum. (d) Mott–Schottky plots collected at a frequency of 5 kHz in the dark for pristine TiO₂ and H:TiO₂ nanowire. Source: Reproduced with permission from Wang et al. [11]. (See color insert.)
FIGURE 3.8 (a) Overlay of Fe 2p XPS spectra of air annealed hematite (denoted as: A-hematite) and oxygen-deficient hematite (denoted as: N-hematite), together with their different spectrums. The dashed lines highlight the satellite peaks of Fe²⁺ and Fe³⁺. (b) Mott–Schottky plots measured for A-hematite and N-hematite. Inset: magnified Mott-schottky plot of N-hematite. (c) Linear sweep voltammograms collected on A-hematite and N-hematite under a simulated solar light of 100 mW cm⁻² and dark condition with a scan rate of 10 mV s⁻¹. (d) The corresponding IPCE spectra for A-hematite and N-hematite collected at potentials of 1.23 and 1.5 V versus RHE. Source: Reproduced with permission from Ling et al. [46]. (See color insert.)
FIGURE 4.1 Pathways from biomass-to-hydrogen. Source: Reproduced with permission from Milne [3].
FIGURE 4.2 Plots for yields of hydrogen-rich gas from pyrolysis of agricultural residues versus temperature in the presence of 30% Na₂CO₃. Source: Reproduced with permission from Demirbas [27].
FIGURE 4.3 Plots for yield of hydrogen from supercritical fluid extraction, pyrolysis, and steam gasification [(W/S) = 2] of beech wood at different temperatures. Source: Reproduced with permission from Demirbas [45].
FIGURE 4.4 A schematic diagram for biohydrogen production from cellulose/starch containing agricultural wastes and food industry wastewaters. Source: Reproduced with permission from Kapdan and Kargi [83].
FIGURE 5.1 A summary of current status of hydrogen storage technologies in terms of weight, volume, and cost. These values are estimates from storage system developers and the R&D community and will be continuously updated by DOE as new technological advancements take place. Source: Reproduced with permission from http://www1.eere.energy.gov/hydrogenandfuelcells/storage/tech_status.html [2]. (See color insert.)
FIGURE 5.2 Compressibility factor of hydrogen. Source: Reproduced with permission from Zhou and Zhou [3].
FIGURE 5.3 TriShield™ Tank construction. Source: Reproduced with permission from http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/32405b27.pdf [5].
FIGURE 5.4 Energy required to compress 1 mole hydrogen from 1 atm at 20°C for a one-stage, a two-stage, and a three-stage compression process. The lowest curve show W_T calculated using Equation (5.12) for the ideal gas case. (See color insert.)
FIGURE 5.5 An example of the polymer electrolyte hydrogen pump (PEHP). Source: Reproduced with permission from Abdulla et al. [9]. (See color insert.)
FIGURE 5.6 A simple phase diagram of hydrogen. Source: Reproduced with permission from Leung et al. [10].
FIGURE 5.7 The illustration of the JT inversion curve (reproduced from Barron [11]) and the JT inversion curves for some conventional gases. Source: Reproduced with permission from Flynn [12]. (See color insert.)
FIGURE 5.8 Schematic and temperature-entropy diagram of a simple Linde cycle. Source: Reproduced with permission from Barron [11]. (See color insert.)
FIGURE 5.9 Schematic and temperature-entropy diagram of a simple Claude cycle. Reproduced with permission from Barron [11]. (See color insert.)
FIGURE 5.10 Schematic illustration of a representative cryogenic vessel. Source: “Hydrogen storage: state-of-the-art and future perspective,” http://publications.jrc.ec.europa.eu/repository/bitstream/111111111/6013/1/EUR%2020995%20EN.pdf. (See color insert.)
FIGURE 6.1 Volumetric and gravimetric hydrogen density of some selected hydrides. Source: Reproduced with permission from Züttel et al. [1].
FIGURE 6.2 The typical PCT curves for the hydrogenation and dehydrogenation of a metal hydride under a fixed temperature T. (See color insert.)
FIGURE 6.3 The van 't Hoff plots of several selected metal hydrides. Source: Reproduced with permission from Zuttel [3]. (See color insert.)
FIGURE 6.4 Potential energy curve for hydrogen binding to a metal: physisorption for both activated and nonactivated processes; dissociation and surface chemisorption; surface penetration and chemisorption on subsurface sites; and diffusion. Source: Reproduced with permission from Zuttel [3].
FIGURE 6.5 Illustration of the four stages of hydrogenation process for a metal powder. (See color insert.)
FIGURE 6.6 Desorption curves of MgH₂ at 573 K in vacuum with Nb₂O₅ catalyst and milled for 2, 5, 10, 20, 50, and 100 hours. Source: Reproduced with permission from Barkhordarian et al. [15].
FIGURE 6.7 Structure of LaNi₅H₇. The sizes of the atom are declined from La, to Ni, to H. Source: Reproduced with permission from figure 2.52 in Sorensen [18]. (See color insert.)
FIGURE 6.8 Targeted range of bond strengths that allow hydrogen release around room temperature. A given material can exhibit both chemisorption and physisorption. Source: Reproduced with permission from Berube et al. [22].
FIGURE 6.9 (Left) SEM image of the Mg nanoblades, and (right) the sorption curves of (a) hydrogen absorption under a hydrogen pressure of 10 bar and (b) hydrogen desorption under vacuum at varying temperatures for V decorated Mg nanoblade array. Source: Reproduced with permission from He et al. [31].
FIGURE 6.10 Arrhenius plots of hydrogen absorption and desorption rate constant k versus reciprocal temperature 1/T for V-decorated Mg nanoblades. Source: Reproduced with permission from He et al [31].
FIGURE 6.11 The spillover mechanism: the hydrogen molecules dissociate on the catalyst. Some hydrogen atoms remain attached to the catalyst, while others diffuse to the catalyst support and subsequently penetrate into the metal, where the hydrogen is said to spill over and interact directly with the metal. Source: Reproduced with permission from Berube et al. [22].
FIGURE 6.12 Comparison of the hydrogenation and dehydrogenation of a large and a small particle: (a) for hydrogenation in a large particle (upper raw), multiple nucleation sites at the surface will merge and form a closed layer that prevents fast diffusion of hydrogen to the core of the particle, slowing down the kinetics of the α- to β-phase transition considerably. If the particle is small (lower raw), fast diffusion of the hydrogen through the α-phase remains possible for a larger fraction of the α- to β-phase transition and (b) for desorption in a large particle (upper raw), hydrogen has to diffuse through a thicker layer of the β-phase before being released, while hydrogen rapidly reaches the surface for a smaller particle (lower raw). Source: Reproduced with permission from Berube et al. [22].
FIGURE 6.13 Equilibrium diagram of the C + H₂ system at 1 atm pressure. Source: Adapted with permission from Baddour and Iwasyk [39]. (See color insert.)
FIGURE 6.14 STM images (4 × 4 nm²) of Ru(000l) acquired at T = 6 K. (a) Surface containing approximately 0.03 mL of C prepared by segregation from the bulk. The C atoms appear as depressions (black spots). (b) After introducing H atoms (from water dissociation in this experiment), C is converted to CH (bright protrusion surrounded by a dark ring). A similar transformation occurs with H obtained from H₂ dissociation. Individual nonreacted H atoms appear as smaller dark spots. Tunneling condition in (a) is V_sample = 50 mV and I_t = 295 pA, and (b) V_sample = 9 mV and I_t = 495 pA. The total z scale is adjusted to be 50 pm in both images. Source: Reproduced with permission from Shimizu et al. [41].
FIGURE 6.15 Images obtained by TEM of the Pd–Mg/SiO₂ catalyst (a) before, and (b) after reaction with respective particle size distributions determined from 100 electron-dense particles. EDS results from the regions indicated in the TEMs are shown with the elemental distributions, (c) and (d). Reproduced with permission from Park and McFarland [48].
FIGURE 6.16 Schematic illustration of the CO₂ methanation process via hydrogenation. S stands for the support, M for the metal, and I for the metal-support interface. Source: Adapted from Marwood et al. [50].
FIGURE 7.1 Hydrogen storage density in physisorbed materials, metal/complex, and chemical hydrides. Source: Reproduced with permission from Niemann et al. [1]. (See color insert.)
FIGURE 7.2 TEM bright-field micrographs of loaded and unloaded DWCNTs: (a) pristine DWCNTs; (b) 1 wt%Pd/DWCNTs; (c) 2 wt%Pd/DWCNTs; and (d) 3 wt%Pd/DWCNTs, with insets in (b), (c), and (d) showing the corresponding selected area electron diffraction patterns. Source: Reproduced with permission from Wu et al. [6].
FIGURE 7.3 Pressure−composition isotherms of (a) N-doped hydrogen exfoliated graphene (N-HEG) and (b) Pd-decorated H-HEG (Pd–N–HEG) in the temperature range 25−100°C and 0.1−4 MPa pressure. Source: Reproduced with permission from Parambhath et al. [15].
FIGURE 7.4 Representative TEM images of parent carbon materials: (a) amorphous carbon, (b) ribbon CNFs, (c) platelet CNFs and (d) fishbone CNFs. Source: Reproduced with permission from Jimenez et al. [25].
FIGURE 7.5 SEM images of different electrospun-activated carbon fibers. Source: Reproduced with permission from Im et al. [28].
FIGURE 7.6 Hydrogen adsorption isotherms of various zeolites at 30°C. Source: Reproduced with permission from Chung [42].
FIGURE 7.7 Different cages in the crystal structure of NOTT-112. Copper: blue–green; carbon: grey; oxygen: red. Water molecules and H atoms are omitted for clarity. Source: Reproduced with permission from Yan et al. [46]. (See color insert.)
FIGURE 7.8 Hydrogen storage capacity at 77 K, and 1 bar of (a) the products and (b) the benchmark materials are shown for comparison. IRMOF stands for isoreticular MOF and MDC for MOD derived. Source: Reproduced with permission from Yang et al. [48]. (See color insert.)
FIGURE 7.9 H₂ gas content as a function of THF concentration, and a schematic diagram of H₂ distribution in the cages of THF+H₂ hydrate. (H₂ gas content is calculated from g of H₂ per g of hydrate, and expressed as wt%.) In region III, H₂ molecules are only stored in small cages, while in region II, both small and large cages can store H₂ molecules. At the highly dilute THF concentrations of region I, H₂ molecules can still be stored in both cages, but extreme pressures (∼2 kbar) are required to form the hydrates. Pure H₂ clathrate (2H₂)₂·(4H₂)·17H₂O would have a 5.002 wt% H2 content. Source: Reproduced with permission from Lee et al. [50]. (See color insert.)
FIGURE 8.1 Temperature and pressure dependence of the reaction rate of H + O₂ (+M) → HO₂ (+M) for M = N₂. Solid lines represent the values used in the mechanism proposed in Li et al. [2], and dashed lines the recommendations of Troe [3]. Source: Reproduced with permission from Li et al. [2].
FIGURE 8.2 Branching ratio of rate constants of the chain branching reaction (H + O₂ = O + OH) and the chain termination reaction (H + O₂ + M = HO₂ + M) as a function of temperature for three different pressures based on two different models: solid lines [2] and dashed lines [1]. Source: Reproduced with permission from Li et al. [2].
FIGURE 8.3 Dependence of maximum [NO] on maximum temperature for different experimental results and numerical simulations [6].
FIGURE 8.4 Flame temperature vs. mass flux at equivalence ratio φ = 0.6. The equivalence ratio is defined as the ratio of the actual fuel/air ratio to the stoichiometric fuel/air ratio. Points: measurements; lines: calculations using different models or reaction mechanisms: GRI-Mech 3.0 (thick solid line) or GRI-Mech 2.11 (dashed line) or Konnov (thin solid line). Source: Reproduced with permission from Haruta and Sano [10].
FIGURE 8.5 Distribution of spot temperature, combustion efficiency (E) and equivalent air ratio (λ₂) over catalyst surface in diffusive combustion. Heat input, 1.2 kcal·cm⁻²·h⁻¹. Equivalent ratio of secondary air, λ₂ = 1.8 0.2. (a) Catalyst T_h, λ₂ = 1.74, E = 83.7 − 87.3%. (b) Catalyst D₅, λ₂ = 1.62, E = 81.2%. (c) Catalyst D₂, λ₂ = 1.96, E = 98.0%. (d) Catalyst G₀, λ₂=1.94, E = 93.0%. Source: Reproduced with permission from Haruta et al. [12].
FIGURE 8.6 (a) H₂ conversion rates and (b) bed temperature changes versus reaction time over the Pt/Ce_0.6Zr_0.4O₂/MgAl₂O₄ cordierite catalyst under different hydrogen concentrations at 263 K as initial temperature (20,000 h⁻¹). Source: Reproduced with permission from Zhang et al. [13].
FIGURE 8.7 Proposed mechanism of catalytic hydrogen combustion over Fe-based compound. Source: Reproduced with permission from Deshpande et al. [14].
FIGURE 9.1 Schematic drawing of a hydrogen/oxygen fuel cell and its reactions based on the proton exchange membrane fuel cell. Source: Reproduced with permission from Carrette et al. [4]. (See color insert.)
FIGURE 9.2 Schematic of PEMFC and stack. Reproduced with permission from Costamanga and Srinivasan [19].
FIGURE 9.3 Basic platinum-based heterogeneous electrocatalyst approaches. Source: Reproduced with permission from Debe [26].
FIGURE 9.4 TEM (a) and HRTEM images (b,c), and SAED (d) of the Pt concave nanocubes recorded along [001] direction. Source: Reproduced with permission from Lim et al. [50].
FIGURE 9.5 TEM (a), HRTEM (b), and HAADF-STEM (c) images, as well as elemental mappings of Pd (d) and Pt (e) metals in Pt–Pd bimetallic nanoparticles, TEM (f) and HRTEM (g) images of carbon-supported Pt–Pd bimetallic catalysts. Source: Reproduced with permission from Peng et al. [50].
FIGURE 9.6 Atomic structure and the space filling stacking model of Fe–Pc (A,C) and Fe–SPc (B,D). Source: Reproduced with permission from Wu et al. [53]. (See color insert.)
FIGURE 9.7 A digital photo image, AFM, and corresponding height analyses of the nitrogen doped grapheme. Source: Reproduced with permission from Gong et al. [54]. (See color insert.)
FIGURE 9.8 SEM (a), low (b) and high (c) magnification TEM images, as well as XPS spectrum (d) of Co₃O₄/grapheme hybrid materials. Source: Reproduced with permission from Liang et al. [55].
FIGURE 9.9 Top view of reduction pathways examined for the adsorbed O atoms on the partially OH(ads)-covered (202) surface of Co₉S₈. Source: Reproduced with permission from Sidik and Anderson [46]. (See color insert.)
FIGURE 9.10 Possible production paths of hydrogen fuel. Source: Reproduced with permission from Carrette et al. [4].
FIGURE 10.1 Schematic diagram of a typical of single stage of hydrocracking system. R, F, and P are reactor, fractionators, and product, respectively. Source: Reproduced with permission from Ward [2].
FIGURE 10.2 Classical mechanism of isomerization and hydrocracking of an alkane on a bifunctional catalyst comprising metal sites for dehydrogenation/hydrogenation and cracking sites. Source: Adapted with permission from Weitkamp [3].
FIGURE 10.3 A proposed mechanism of hydrogenolysis of chlorobenzene on nickel-chromium metal. Z_H and Z_R indicate hydrogen absorption sites and reactant absorption sites, respectively [4].
FIGURE 10.4 Hagg–Dessau cracking mechanism for an alkane molecule proceeding via a carbonium ion transition state [7].
FIGURE 10.5 Proposed mechanism for hydrolysis of alkyl cyclohexanes on MoS₂ catalyst surface [8].
FIGURE 10.6 A flow chart illustration of the main components in a typical Haber process [11].
FIGURE 10.7 A schematic diagram illustrates partial hydrogenation of a triacylglycerol. The reactant is a typical kind of vegetable oil and the product is a typical component of margarine [14].
FIGURE 10.8 SEM images show different morphologies of Mo metals obtained from hydrogen reduction under (left) low and (right) high moisture content. Source: Reproduced with permission from Schulmeyer [17].
FIGURE 10.9 Schematic diagram illustrating the device for arc-atom welding. Source: Reproduced with permission from Suban et al. [18].
FIGURE 10.10 Thermal conductivity of various gases measured at different temperatures. Source: Reproduced with permission from Suban et al. [18].