Real-Space Visualization of CO₂ Capture, Diffusion, and Release in Surface-Confined Metal-Organic Frameworks

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) are promising for carbon dioxide (CO2) capture and conversion.
• Understanding CO2 diffusion and host-guest interactions in MOFs is limited by imaging challenges.

Purpose of the Study:

• To visualize CO2 binding configurations and dynamics within surface-confined MOFs at the molecular level.
• To elucidate CO2 adsorption and diffusion mechanisms using real-space imaging.

Main Methods:

• In situ CO2 dosing combined with atomic-resolution scanning probe microscopy.
• Bond-resolved imaging to identify CO2 adsorption configurations.
• Temperature-dependent measurements to study CO2 capture dynamics.

Main Results:

• Direct visualization of two distinct CO2 adsorption configurations based on MOF interactions.
• Identification of organized CO2 patterns within MOF pores.
• Observation of MOF instability and collapse under high CO2 concentrations.

Conclusions:

• CO2 capture in surface-confined MOFs is a dynamic, nonequilibrium process.
• Real-space imaging provides powerful insights into gas adsorption and diffusion mechanisms.
• MOF structural stability is sensitive to CO2 concentration changes.