Correlation between coordinated water content and proton conductivity in Ca-BTC-based metal-organic frameworks

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nanotechnology

Background:

• Proton conductivity in materials is crucial for energy applications like fuel cells.
• Metal-organic frameworks (MOFs) offer tunable structures for ion transport.
• Water molecules can significantly influence proton mobility in porous materials.

Purpose of the Study:

• To investigate the proton conductivity of calcium-based MOFs.
• To understand the role of coordinated water molecules in proton transport.
• To correlate structural features with proton conductivity performance.

Main Methods:

• Synthesis of five distinct calcium-based MOFs.
• Characterization of MOF structures and water coordination.
• Measurement of proton conductivity at various temperatures.
• Analysis of hydrogen bonding interactions.

Main Results:

• Proton conductivity was observed in all five Ca-based MOFs.
• Conductivity values were found to be dependent on the number of water molecules coordinated to Ca-centers.
• High-temperature proton conductivity was attributed to strong hydrogen bonding networks.
• A correlation between water content and proton mobility was established.

Conclusions:

• Calcium-based MOFs can function as proton conductors.
• The degree of water coordination to Ca-centers is a key factor in tuning proton conductivity.
• Strong hydrogen bonding is essential for facilitating proton transport at elevated temperatures in these MOFs.