Evaluating Diatomaceous Earth for Long-Term Use in Hydrogen Storage

Area of Science:

• Materials Science
• Energy Storage
• Geochemistry

Background:

• Efficient hydrogen storage is crucial for sustainable energy applications.
• Diatomaceous earth, a natural siliceous material, possesses high surface area and is explored for hydrogen physisorption.

Purpose of the Study:

• To investigate the long-term effects of high-pressure hydrogen exposure on diatomaceous earth.
• To evaluate changes in material properties and hydrogen adsorption capacity after prolonged hydrogen interaction.

Main Methods:

• Subjecting diatomaceous earth to 1200 psi hydrogen pressure for 80 days at room temperature.
• Analyzing morphological, mineralogical, and surface area (BET) changes.
• Measuring hydrogen adsorption capacity at 77 K before and after the test.

Main Results:

• No significant morphological or mineralogical alterations were observed.
• A slight decrease in fine particles and an increase in larger particles were noted.
• Brunauer-Emmett-Teller (BET) surface area decreased slightly, with a significant reduction in pore width.
• Hydrogen adsorption capacity at 77 K increased by 45.5% post-treatment.
• Delayed release of molecular water indicated condensation reactions forming siloxane bonds, increasing hydrophobicity.

Conclusions:

• The observed changes, particularly increased hydrophobicity and reduced pore width, enhance hydrogen adsorption.
• Diatomaceous earth demonstrates potential for long-term hydrogen storage, with capacity potentially improving over time.
• The material's structural and chemical modifications under hydrogen pressure are key to its enhanced performance.