Accelerated C₂H₂/CO₂ Separation by a Se-Functionalized Porous Coordination Polymer with Low Binding Energy

Area of Science:

• Materials Science
• Chemical Engineering
• Chemistry

Background:

• Acetylene (C2H2) is a vital precursor for synthesizing various high-value chemicals.
• Selective separation of acetylene from carbon dioxide (CO2) is challenging due to their similar physical properties and acetylene's reactivity.
• Existing porous materials struggle with efficient and selective acetylene capture.

Purpose of the Study:

• To develop a novel porous material for the selective capture of acetylene from CO2.
• To investigate the mechanism behind the selective adsorption of acetylene by the new material.
• To demonstrate the practical application of the material in gas separation.

Main Methods:

• Synthesis of a new porous coordination polymer (PCP), NTU-55, incorporating copper dimers and selenium-containing ligands.
• Static single-component gas adsorption experiments to determine adsorption capacities.
• Dynamic breakthrough experiments to evaluate separation performance in C2H2/CO2 mixtures.
• Density Functional Theory (DFT) calculations to elucidate the adsorption mechanism.

Main Results:

• Desolvated NTU-55 demonstrated complete adsorption of acetylene from a C2H2/CO2 mixture (1/4, v/v) at 298 K.
• The material exhibited higher acetylene capacity and significantly lower binding energy compared to CO2.
• DFT calculations revealed that selective adsorption originates from the distinct interactions of C2H2 and CO2 with accessible selenium and copper sites.
• This study marks the first report on the beneficial role of nonmetal selenium sites in selective acetylene capture.

Conclusions:

• NTU-55 is a highly effective adsorbent for selective acetylene capture from CO2.
• The presence of nonmetal selenium sites is crucial for achieving superior separation performance.
• This work offers a promising strategy for acetylene purification in industrial applications.