Self-Healing Hydrogen-Bonded Organic Frameworks for Low-Concentration Ammonia Capture

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Intelligent sensing systems utilize self-healing properties for molecular recognition.
• Rigid crystalline frameworks often fail to recover their structure after external stimuli-induced collapse.
• Developing recoverable frameworks is crucial for advanced material applications.

Purpose of the Study:

• To report the self-healing behavior of a novel microporous hydrogen-bonded organic framework, FDU-HOF-3.
• To investigate the ammonia (NH3) capture capabilities of FDU-HOF-3 and compare it with HOF-101.
• To elucidate the mechanism behind the self-healing property in these frameworks.

Main Methods:

• Synthesis and characterization of FDU-HOF-3, a new microporous hydrogen-bonded organic framework.
• Ammonia (NH3) adsorption/desorption experiments under varying conditions.
• Analysis of structural changes and recovery mechanisms using advanced characterization techniques.
• Photocurrent measurements to assess sensing capabilities for NH3.

Main Results:

• FDU-HOF-3 exhibits reversible self-healing, recovering its crystalline phase after NH3 exposure and vacuum heating.
• The self-healing mechanism involves acid-base interactions (COOH-NH3) and hydrogen bond (COOH-COOH) dynamics.
• FDU-HOF-3 demonstrates a record ammonia capture capacity (8.13 mmol/g at 25 mbar) among HOFs.
• The material shows rapid photocurrent response to 250 ppm NH3 and maintains performance over 10 adsorption-release cycles.

Conclusions:

• The developed self-healing HOFs offer a promising platform for robust ammonia capture and sensing.
• The reversible structural recovery mechanism enhances the durability and reusability of the material.
• FDU-HOF-3 presents superior performance for low-concentration ammonia capture compared to existing HOFs.