Bioinspired Reconfiguration of Alkylamines into Metal-Organic Frameworks for Robust Direct Air Capture

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Direct air capture (DAC) of CO2 faces challenges with current adsorbents showing diminishing returns.
• Functionalization strategies for molecularly engineered or polymer-based CO2 adsorbents have plateaued.
• Protein folding principles inspire novel approaches to sorbent discovery.

Purpose of the Study:

• To introduce a new dimension for CO2 sorbent discovery using structurally reconfigured alkylamines into a polycyclic linker.
• To incorporate a dimeric butylamine linker into a metal-organic framework (MOF), creating NUS-110.
• To evaluate the direct air capture capacity, humidity tolerance, and oxidative stability of the novel MOF.

Main Methods:

• Structurally reconfiguring alkylamines into a polycyclic linker inspired by protein folding.
• Incorporating the dimeric butylamine linker into a metal-organic framework (NUS-110) via a mechanochemical approach.
• Assessing DAC capacity under dry and humid conditions, evaluating oxidative stability over 20 cycles, and performing dynamic breakthrough experiments.

Main Results:

• NUS-110 achieved a DAC capacity of 0.89 mmol/g (dry) and 1.35 mmol/g (humid).
• The MOF demonstrated strong water tolerance with sigmoidal adsorption behavior and exceptional oxidative stability.
• Humid conditions enhanced adsorption kinetics through water-assisted reaction pathways, confirming practical viability.

Conclusions:

• A paradigm shift in DAC sorbent development is introduced, moving beyond traditional functionalization.
• NUS-110 offers enhanced humidity tolerance and oxidative resilience, making it suitable for practical deployment.
• The polycyclic linker strategy represents a promising avenue for next-generation CO2 capture materials.