Flexible and hydrophobic Zn-based metal-organic framework

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) are advanced porous materials with tunable structures.
• MOFs offer potential applications in gas storage, separation, and catalysis.
• Understanding MOF phase transitions is crucial for optimizing their performance.

Purpose of the Study:

• To synthesize and characterize a new zinc-based MOF, DUT-30(Zn).
• To investigate the structural transformations and guest-dependent phases of DUT-30(Zn).
• To evaluate the gas storage properties of the activated DUT-30(Zn) for hydrogen, CO2, and n-butane.

Main Methods:

• Solvothermal synthesis route for DUT-30(Zn).
• Single crystal X-ray diffraction for structural characterization of different phases.
• Nitrogen physisorption to determine surface area and pore volume.
• In situ X-ray powder diffraction to monitor gas adsorption processes.

Main Results:

• DUT-30(Zn) exhibits six crystallographic guest-dependent phases, with two characterized (K and T).
• Activated DUT-30(Zn) (phase A) shows a BET surface area of 960 m²/g and a pore volume of 0.43 cm³/g.
• Demonstrated hydrogen storage of 1.12 wt%, CO2 uptake of 200 cm³/g at -78°C, and n-butane uptake of 3.0 mmol/g.
• Structural transformations were observed upon guest removal, cooling, and interaction with nitrogen or water.

Conclusions:

• DUT-30(Zn) is a versatile MOF with multiple accessible phases.
• The framework's porosity and gas uptake capabilities make it suitable for gas storage applications.
• Further research into phase control could enhance its performance for specific applications.