# Presentation: 938033

## Allows NMR during dehydriding 
	and rehydriding at hi-T, hi-P
Glass sample vessel supported
	by external pressure:

Argon held by cold pressure wall-no weakening at hi-T.
Current version to 400 C, 
	to 55 atm, hydrogen NMR.
Next version:  to 120 atm; deuterium, 
	27Al, 23Na, Ti, B; with internal rf tuning.
Accepted for publication in 
	Review of Scientific Instruments. 

- 	and rehydriding at hi-T, hi-P
- Glass sample vessel supported
- 	by external pressure:
- Argon held by cold pressure wall-no weakening at hi-T.
- Current version to 400 C,
- 	to 55 atm, hydrogen NMR.
- Next version:  to 120 atm; deuterium,
- 	27Al, 23Na, Ti, B; with internal rf tuning.
- Accepted for publication in
- 	Review of Scientific Instruments.

- High-Temperature, High-Pressure NMR Apparatus for *in situ* Study of Hydrogen Storage CompoundsMark Conradi, Washington University, Department of Physics, St. Louis, MODMR 0400512

## High-Temperature, High-Pressure NMR Apparatus for in situ Study of Hydrogen Storage CompoundsMark Conradi, Washington University, Department of Physics, St. Louis, MODMR 0400512

- On-board storage of hydrogen fuel is the largest hurdle on the path to the envisioned hydrogen energy economy.
- There are new solid-state candidate systems, like NaAlH4, LiNH2, and LiBH4, e.g., overall chemistry of NaAlH4 is
- But the *mechanisms *of dehydriding and rehydriding and their catalysis remain unknown.  Understanding the mechanisms would help us optimize the materials and design better ones.
*In situ* NMR, under the actual conditions of hi-T and hi-P used to de/rehydride, promises to identify the mobile and chemically intermediate species involved.
- Thus the new apparatus should help us understand the chemistry of the hydrogen storage solid compounds and help us design improved storage systems.

**Notes:**
The current hydrogen storage compounds have inadequate storage density (i.e., driving miles per kilogram of material), even though the solids are much better than the leading alternative, compressed gas storage.
Interest in NaAlH4  was renewed by the discovery that Ti compounds can catalyze de/rehydriding, speeding up the reactions at a given temperature.  But how the catalysts function remains unknown after years.
Nuclear magnetic resonance is widely used in chemistry and physics to analyze unknowns.  Here the promise is that NMR will identify reactive intermediates – the chemical compounds formed fleetingly, partway through the reaction.

## High-Temperature, High-Pressure NMR Apparatus for in situ Study of Hydrogen Storage CompoundsMark Conradi, Washington University, Department of Physics, St. Louis, MODMR 0400512

- The current hydrogen storage compounds have inadequate storage density (i.e., driving miles per kilogram of material), even though the solids are much better than the leading alternative, compressed gas storage.
- Interest in NaAlH4  was renewed by the discovery that Ti compounds can catalyze de/rehydriding, speeding up the reactions at a given temperature.  But how the catalysts function remains unknown after years.
- Nuclear magnetic resonance is widely used in chemistry and physics to analyze unknowns.  Here the promise is that NMR will identify reactive intermediates – the chemical compounds formed fleetingly, partway through the reaction.