Hydrogen storage in mesoporous titanium oxide-alkali fulleride composites

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Mesoporous materials are crucial for gas storage applications.
• Fullerides, salts of the fullerene anion, are explored for their unique electronic properties and potential in hydrogen storage.
• Titanium oxide-based composites offer a tunable platform for material design.

Purpose of the Study:

• To synthesize and characterize mesoporous titanium oxide-alkali fulleride composites.
• To investigate the hydrogen sorption properties of these composites at various temperatures and pressures.
• To compare the hydrogen storage performance of fulleride-containing composites with pristine and fulleride-free materials.

Main Methods:

• Synthesis of mesoporous titanium oxide-alkali fulleride composites.
• Characterization using X-ray diffraction, nitrogen adsorption, Raman spectroscopy, and elemental analysis.
• Hydrogen sorption measurements at 77 K, room temperature, and 200°C under pressures up to 100 atm.

Main Results:

• The lithium fulleride composite achieved a volumetric uptake of 27.35 kg/m³ at 77 K and 100 atm, lower than some previously reported materials.
• At room temperature, gravimetric storage and adsorption were 0.99 and 0.11 wt%, respectively, slightly higher than the unreduced material.
• Inclusion of fulleride units decreased overall gravimetric and volumetric storage compared to fulleride-free counterparts.
• Enthalpies of reduced composites showed an increasing trend with surface coverage, indicating titanium oxide as the main binding site.

Conclusions:

• Incorporating alkali fullerides into mesoporous titanium oxide reduces hydrogen storage capacity.
• The reduced titanium oxide surface is the primary contributor to hydrogen binding sites.
• Further research may focus on optimizing composite structures for enhanced hydrogen storage.