Functionalized Base-Stable Metal-Organic Frameworks for Selective CO₂ Adsorption and Proton Conduction

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) are promising for CO2 capture and proton conduction.
• Enhancing chemical stability and optimizing properties are key for practical MOF applications.

Purpose of the Study:

• To design, synthesize, and evaluate three base-stable, isostructural MOFs with varying functional groups (CHO, CN, COOH) for CO2 capture and proton conduction.
• To investigate the structure-property relationships influenced by functionalization.

Main Methods:

• Synthesis of isostructural Ni-BDP-X MOFs ([Ni8(OH)4(H2O)2(BDP-X)6]).
• Characterization of MOF structures and stability in harsh conditions (boiling water, 4M NaOH).
• Evaluation of CO2 capture selectivity (over CH4, N2) and proton conductivity.

Main Results:

• Synthesized three stable, face-centered cubic MOFs (Ni-BDP-X) with functional nanoscale cavities.
• MOFs maintained structural integrity in boiling water and 4M NaOH.
• Demonstrated selective CO2 adsorption, with COOH functionalization yielding the highest selectivity.
• COOH-functionalized Ni-BDP achieved a proton conductivity of 2.22×10^-3 S/cm at 80°C and 97% RH.

Conclusions:

• The designed MOFs exhibit remarkable base stability and tunable properties through functionalization.
• These MOFs are effective for selective CO2 capture.
• The COOH-functionalized MOF shows significant potential for proton conduction applications.