The Rocky Road to The Rocky Road to a Hydrogen a Hydrogen EconomyEconomy
Presented By Rebecca Armstrong Presented By Rebecca Armstrong
April 18, 2008April 18, 2008
Advisor Boris KieferAdvisor Boris Kiefer
IntroductionIntroduction
•Why Hydrogen Economy•Current ideas •Our ideas •Future
97% Transportation Fuel Crude Oil
25% greenhouse emissions
Materials for hydrogen storage: current research trends and perspectivesAnnemieke W. C. van den Berg{a and Carlos Otero Area´n*b
About 75% of the materials we use for energy are conventional fossil fuels.
Hydrogen is much cleaner than fossil fuels
Hydrogen stores 2.6 times more energy per Hydrogen stores 2.6 times more energy per mass unit than gasolinemass unit than gasoline
Hydrogen-storage materials for mobile applicationsLouis Schlapbach*† & Andreas Züttel†
Mg2NiH4 LaNi5H6 H2 (liquid) H2 (200 bar)
CUTE (Clean Urban Transportation for Europe)
27 Hydrogen fuel cell buses
2015 – 170 fuel cell buses 73 Hydrogen
Materials for hydrogen storage: current research trends and perspectivesAnnemieke W. C. van den Berg{a and Carlos Otero Area´n*b
Conversion and Storage of Energy
http://dsc.discovery.com/news/2008/04/03/hydrogen-plane-zoom.html
TWO PROBLEMSTWO PROBLEMS
1.Fuel Cell – Solved
2.Storage - Unsolved
Other Ideas!Other Ideas!
• Hydrides
• Zeolites
• Nanotubes
We took a different route and came up with the following.
http://www.umass.edu/sbs/news_events/news_stories/nanotech.htm
http://www.chem.arizona.edu/courses/c518_2003/tgb518/public_html?N=D
http://www.flickr.com/photos/ghutchis/124782973/
Five commandments Five commandments of hydrogen storageof hydrogen storage
• (i) High storage capacity: minimum 6.5 wt %
• (ii) Tdec 60-120 °C.
• (iii) Reversibility of the thermal absorption/
desorption cycle: • (iv) Low cost.• (v) Low-toxicity of a nonexplosive and possibly
inert (to water and oxygen) storage medium.
Thermal Decomposition of the Non-Interstitial Hydrides for the Storage andProduction of Hydrogen Wojciech Grochala*,†,‡ and Peter P. Edwards*,§The School of Chemistry, The University of Birmingham, Edgbaston, Birmingham, B15 2TT U.K., The Department of Chemistry, The University ofWarsaw, Pasteur 1, 02093 Warsaw, Poland, and Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR U.K.
ModelModel
• The Human Body
• Uses Iron to transfer oxygen throughout the body
• The transferring
molecule…
Hemoglobin
http://www.lipitor-online.com/imgs/cholesterol-human-body.jpg
Heme GroupsHeme Groups
http://www.chemistry.wustl.edu/~edudev/LabTutorials/Hemoglobin/MetalComplexinBlood.html#ChangeMovie
Hemoglobin: active site
Heat of FormationHeat of FormationA + B + … A + B + … C + D + … C + D + …
• ΔE = EP – ER < 0 exothermic reaction. energy is released. more stable state.
• ΔE = EP – ER > 0 endothermic reaction. energy is absorbed. less stable state.
Example: Formation of waterH2 (g) + ½ O2 (g) H2O(l) ΔE=-284 kJ/mole
EEReactantsReactants= E= EAA + E + EBB + … + … E ECC + E + EDD + …= E + …= EProductsProducts
Transition Metals - OTransition Metals - O22 Binding Binding
Fe + O2 and Fe + 2 O2
Stable
Hydrogen Storage: Replace O2 H2.
What transition metal to What transition metal to choose?choose?
Requirements:
• Adsorb H2, no chemical reaction.• Maximum number of adsorbed molecules.
need maximum number of unpaired electrons. Manganese.
Storage Capacities:Storage Capacities:
• Our mechanism: Maximum storage capacity : 15.3 wt% hydrogen. • (Li,Mg)NH2 : 5.2 wt%.
• LiBH4 : 5.4 – 9.6 wt%.
• Current DOE goal: 7.8 wt%.
http://www.hydrogen.energy.gov/pdfs/5037_h2_storage.pdf
Mn + H2 Mn-H2
Mn + 2H2 Mn-2H2
Compound has a stable geometry.But: product has a higher energy than the
reactants unlikely that transition provide efficient storage medium for H2.
Manganese and HydrogenManganese and Hydrogen
-1000
-800
-600
-400
-200
0
200
400
600
H2
- B
ind
ing
Ene
rgy
(kJ/
mo
l)
0 I II III IV
Oxidation State
CIV
Unstable
Stable H2 adsorption
MnIII
FeIII
CoIII
Li0
Mg0
Li C Na Mg Al Co Mn Fe
Mn0
Fe0
Co0
Hydrogen Adsorption EnergiesHydrogen Adsorption Energies• Li too stable(hydride).
• Mg too stable(hydride).
• Carbon - nanotubes?Likely low storage.
• Na: low storagecapacity.
• Other elements toostable?
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
H2
- B
ind
ing
En
erg
y (k
J/m
ol)
0 I II III IV
Oxidation State
Na: adsorption capacity too low
Mg, Mn too stable
Al too stable
C? 300 K
Hydrogen Adsorption EnergiesHydrogen Adsorption Energies• Li too stable(hydride).
• Mg too stable(hydride).
ConclusionConclusion
• Lots of ideas that are being worked on. None meeting more than a two commandments.
• Our idea does not bind, but through other ideas we might find something else
• Hydrogen as a fuel is possible, we just need to continue research on how to store it.
• We do not see according to our simplified model across
the periodic table elements do not bind H2.
It is a Rocky Road.It is a Rocky Road.
THE ENDTHE END