Hydrogen Storage in Ti-doped NaAlH4 William Gempel

National Hydrogen Initiative President Bush has proposed $1.2 billion over the next five years to support a new Hydrogen Fuel Initiative.

Elements of a Hydrogen Energy Infrastructure Production Delivery Storage Conversion Applications

Hydrogen Storage Methods High Pressure Tanks Liquid Hydrogen Carbon Nanotube Surface Absorbtion MgH 2 NaAlH 4

Comparison of Methods Method% Weight HVolume 1kg H H Gas 200 bar100.06m^3 H Liquid m^3 C-Nanotube~6-8.02m^3 MgH m^3 NaAlH (5.6).010m^3

Reversible Hydrogen Exchange in Metal Hydrides H 2 absorbed under pressure H atoms bond to metal H 2 released at elevated temperature

Sodium Alanate 3NaAlH 4 -> Na 3 AlH 6 + 2Al +3H 2 Na 3 AlH 6 -> 3NaH + Al + 3/2H % Hydrogen by Weight $50 per kg Slow Kinetics Reversible only at ~600 K

Ti-Doped Sodium Alanate Reversible at ~450 K Kinetics 2-4 times faster Still unsatisfactory, but Working model for possibility of catalytic improvement

Sodium Alanate Structure Body Centered Tetragonal Space Group IA/4 Lattice ~5x11 Ang.

First Principle Calculations for Sodium Alanate Geometry Electronic Structure Energy of Formation

First Principles Calculations for Ti-Doping Structurally Stable Ti Prefers to Substitute for Na Ti Softens Al-H bonds It is energetically favorable for Ti to drag extra H into the system

First Principle Studies of Analogous Systems M x H Electronic Structure Energy of Formation Cohesive Energy Metal-Hydrogen Bond Strength

Local Projects Comparing CASTEP to VASP Reproducing Calculations in Literature Sodium Alanate Structure (In Progress) Energy of Formation Titanium Valence (Population Analysis)?

Conclusion Ti – Doped Sodium Alanate Experiments show that Catalytic methods can be used to improve operation of Metal Hydrides First Principle Calculations may lead to understanding of mechanism that will allow improved Catalytic Methods