Interlayer Symmetry Control in Flexible-Robust Layered Metal-Organic Frameworks for Highly Efficient C₂H₂/CO₂...

Area of Science:

• Materials Science
• Chemical Engineering
• Adsorption Science

Background:

• Efficient separation of acetylene (C₂H₂) from carbon dioxide (CO₂) is crucial for producing high-purity acetylene.
• Developing adsorbents that can discriminate between C₂H₂ and CO₂, which have similar kinetic diameters, is essential for advanced adsorption processes.

Purpose of the Study:

• To design and synthesize a novel two-dimensional (2D) layered metal-organic framework (MOF) for selective C₂H₂/CO₂ separation.
• To investigate the tunability of interlayer and intralayer spaces in MOFs for enhanced adsorption performance.

Main Methods:

• Synthesis of Ni(4-DPDS)₂CrO₄, an isostructural series of Ni(4-DPDS)₂MO₄ (M = Mo, W) MOFs.
• Characterization using crystallographic studies.
• Computational analysis using Density Functional Theory with dispersion corrections (DFT-D).
• Experimental breakthrough tests for gas separation performance evaluation.

Main Results:

• Ni(4-DPDS)₂CrO₄ demonstrated a high C₂H₂ uptake of 45.7 cm³·g^-1 at 0.01 bar and a selectivity of 67.7 at 298 K and 1 bar for C₂H₂/CO₂ mixtures.
• Interlayer symmetrical control facilitated efficient packing of C₂H₂ within the MOF structure.
• Tailored pore confinement and electronic environment led to strong binding interactions with C₂H₂.

Conclusions:

• The developed 2D MOF, Ni(4-DPDS)₂CrO₄, exhibits excellent performance for C₂H₂/CO₂ separation, balancing working capacity and selectivity.
• The strategy of exploiting tunable pore spaces in layered MOFs is effective for designing advanced adsorbents.
• This material shows significant potential for industrial applications in high-purity acetylene production.