Optimized acetylene/carbon dioxide sorption in a dynamic porous crystal

Area of Science:

• Materials Science
• Chemistry
• Chemical Engineering

Background:

• Acetylene (C(2)H(2)) has a low compression limit, hindering its storage and application.
• Developing effective adsorbents for C(2)H(2) is challenging due to its similarity to carbon dioxide (CO(2)).

Purpose of the Study:

• To investigate the C(2)H(2)/CO(2) sorption behaviors of a metal azolate framework, MAF-2.
• To elucidate the role of pore characteristics and framework dynamics in gas adsorption.

Main Methods:

• Gas sorption measurements.
• Single-crystal X-ray crystallography of C(2)H(2) and CO(2) sorption complexes.
• Analysis of framework dynamics and pore characteristics.

Main Results:

• MAF-2 exhibits unique static and dynamic pore characteristics enabling selective C(2)H(2)/CO(2) sorption.
• Single-crystal analysis revealed distinct configurations of C(2)H(2)/CO(2) hexamers within MAF-2 nanocages.
• Sigmoid isotherms were observed, indicating optimized adsorption for practical applications.
• High C(2)H(2) uptake (70 cm(3) g(-1)) and C(2)H(2)/CO(2) ratio (3.7) at 298 K, 1 atm were achieved.
• Usable C(2)H(2) storage capacity was significantly higher than gas cylinders.

Conclusions:

• The unique pore characteristics and framework dynamics of MAF-2 lead to extraordinary C(2)H(2)/CO(2) sorption behaviors.
• MAF-2 presents a promising material for efficient acetylene storage and separation applications.