High Hydrogen Storage in Trigonal Prismatic Monomer-Based Highly Porous Aromatic Frameworks

Area of Science:

• Materials Science
• Chemical Engineering
• Energy Storage

Background:

• Hydrogen storage is critical for a carbon-neutral society, with porous materials offering a promising alternative to current energy-intensive methods.
• Efficient hydrogen storage is key to utilizing hydrogen as a renewable energy source.

Purpose of the Study:

• To synthesize and characterize two novel porous aromatic frameworks (PAFs), C-PAF and Si-PAF, for advanced hydrogen storage applications.
• To evaluate the hydrogen storage capacity, volumetric and gravimetric, and stability of the synthesized PAFs.

Main Methods:

• Yamamoto C─C coupling reaction was used to synthesize C-PAF and Si-PAF from trigonal prismatic monomers.
• Brunauer-Emmett-Teller (BET) analysis was performed to determine pore volumes and surface areas.
• Hydrogen storage capacity was measured under pressure-temperature swing adsorption (PSA) conditions (77 K, 100 bar → 160 K, 5 bar).
• Computational modeling was employed to investigate structural and adsorption properties.

Main Results:

• C-PAF and Si-PAF exhibited large pore volumes (3.93 cm³ g⁻¹ and 3.80 cm³ g⁻¹) and BET surface areas (4857 m² g⁻¹ and 6099 m² g⁻¹).
• Si-PAF demonstrated a record gravimetric hydrogen storage capacity of 17.01 wt% and a volumetric capacity of 46.5 g L⁻¹.
• Both PAFs displayed excellent structural stability and long-term durability due to robust C─C covalent bonds.

Conclusions:

• C-PAF and Si-PAF are highly promising materials for efficient and stable hydrogen storage.
• The high gravimetric and volumetric capacities of Si-PAF surpass existing benchmark materials.
• These PAFs represent a significant advancement in materials for renewable energy storage.