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Transcript of Hydrogen Storage in Nano-Porous Materials The University of Oklahoma School of Chemical, Biological,...
Hydrogen Storage Hydrogen Storage in Nano-Porous Materialsin Nano-Porous Materials
The University of OklahomaSchool of Chemical, Biological, and Materials Engineering
Dimitrios ArgyrisDimitrios Argyris
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Introduction
• Petroleum dependence → U.S. imports 55% of its oil expected to grow to 68% in 2025
• Hydrogen as energy carrier → clean, efficient, and can be derived from domestic resources
Renewable(biomass, hydro, wind, solar, and geothermal)
Fossil fuels(coal ,natural gas, etc.)
Nuclear Energy
Hydrogen storage
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Introduction
• Hydrogen storage is a critical enabling technology for the acceptance of hydrogen powered vehicles
• Storing sufficient hydrogen on board to meet consumers requirements (eg. driving range, cost, safety, and performance)
is a crucial technical parameter
• No approach currently exists that meets technical requir. driving range > 300 miles
• U.S. DoE → develop on board storage systems achieving 6 and 9 wt% for 2010 and 2015
Hydrogen storage
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Storage Approaches
Reversible on board
• Compressed hydrogen gas, Liquid hydrogen tanks, Metal hydrides, Porous materials
Regenerable off-board
• Hydrolysis reactions, hydrogenation/dehydrogenation reactions, ammonia borane and other boron hydrides, alane (metal hydride), etc.
Porous materials: usually carbon based materials with high surface area
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Porous Materials
High surface area sorbents
Storage Approaches
• Single walled carbon nanotubes (CNT)
• Graphite materials
• Carbon nanofibers
• Metal-organic framework
• Theoretical studies: organometallic buckyball fullerenes, Si-C nanotubes
Advantages: High surface area → fast hydrogen kinetics and low hydrogen binding energies → fewer thermal management issues
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Synthesis
Metal-Organic Frameworks
HKUST-1*
*www.esrf.eu/
O (red)C (gray)H (white)
Cu (purple) HKUST-1, Cu2(C9H3O6)4/3
• benzene-1,3,5-tricarboxylic acid heated with copper nitrate hemipentahydrate
in solvent consisting of equal parts of N,N-dimethylformamide (DMF), ethanol, and deionized water →
filtration, drying, and solvent removal → porous material: HKUST-1
3 different metal organic frameworks
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Synthesis
Metal-Organic Frameworks
HKUST-1
MIL-101
COF-1
Covalent-Organic Frameworks
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Characterization
X-ray diffraction
X-ray diffraction patterns of (a) COF-1, HKUST-1, and (b) MIL-101.
All samples show good crystallinity
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Characterization
Infra-red spectra
Infra-red spectra of COF-1 (a)
Vibrational bands
1376 and 1340 cm-1→ B–O stretching
1023 cm-1 → B–C bonds
708 cm-1 → B3O3 ring units
MIL-101 (c)
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Characterization
Scanning Electron Microscopy
COF-1 (a)
HKUST-1 (b)
Unique morphology of particles in each material
• COF-1: 0.3-0.4 μm
• HKUST-1: 4.0-8.0 μm
• MIL-101: 0.2-0.3 μm
Particles Size
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Characterization
BET surface area
BET surface area and pore volume → N2 adsorption at 77 K
• COF-1: 628 0.36
• HKUST-1: 1296 0.69
• MIL-101: 2931 1.45
BET surface area (m2/g) Pore volume (cm3/g)
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Characterization
Hydrogen Adsorption
• COF-1: 1.28 0.26
• HKUST-1: 2.28 0.35
• MIL-101: 1.91 0.51
H2 Uptake (wt %)(77 K and 1 atm)
H2 Uptake (wt %)(298 K and 10 MPa)
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Characterization
Hydrogen Adsorption
Hydrogen adsorption at 298 K
MIL-101
Pure MIL-101
Pt/AC and MIL-101 physical mixture (1:9 mass)
MIL-101 - bridges - Pt/AC
Bridged spillover → hydrogen adsorption increased by a factor of 2.6 – 3.2
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Molecular Simulations
GCMC simulations → Predict adsorption isotherm for H2 →10 isoreticular metal – organic frameworks (IRMOFs)
Oxide - centered Zn4O tetrahedra each
connected by six dicarboxylate linkers†
IRMOFs
3D cubic networkvery high porosity
† variety of linkers can be used to get different pore sizes
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Molecular Simulations
Results Adsorption isotherms at 77 K
IRMOF-1, -4 , -6, -7
Low Pressure Low Pressure
High Pressure
IRMOF-10, -16
High Pressure
Narrow pores materials:
High levels of adsorption
High levels of adsorption
Materials with high free volume:
High uptake of H2
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Molecular Simulations
Simulation Snapshots
Low pressure (0.01 bar)
High pressure(120 bar)
H2 near zinc corners Molecules preferentially in zinc corners and along linkers
Intermediate pressure(30 bar)
H2 fills the majority of the void regions of material
Hydrogen Storage in Nano-Porous MaterialsHydrogen Storage in Nano-Porous Materials
Questions?