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


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


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


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


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


Synthesis

Metal-Organic Frameworks

HKUST-1

MIL-101

COF-1

Covalent-Organic Frameworks


Characterization

X-ray diffraction

X-ray diffraction patterns of (a) COF-1, HKUST-1, and (b) MIL-101.

All samples show good crystallinity


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)


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


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)


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)


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


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



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



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


Questions?

hydrogen storage in nano-porous materials the university of oklahoma school of chemical, biological,...

Documents

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chydrogen storage

board storage systems

acceptance of hydrogen

sufficient hydrogen

board compressed hydrogen

liquid hydrogen tanks

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