Donor-Acceptor Covalent-Organic Frameworks Based on Phthalimide as an Electron-Deficient Unit for Efficient...

Area of Science:

• Materials Science
• Photocatalysis
• Renewable Energy

Background:

• Two-dimensional covalent-organic frameworks (COFs) are promising photocatalysts due to their tunable structures and porosity.
• Donor-acceptor COFs offer potential for enhanced light absorption and charge separation.
• Phthalimide, a novel acceptor unit, was explored for COF construction.

Purpose of the Study:

• To synthesize novel donor-acceptor COFs using phthalimide as an acceptor unit.
• To investigate the photocatalytic performance of these COFs for hydrogen evolution.
• To evaluate the effect of platinum co-catalysis on hydrogen evolution efficiency.

Main Methods:

• Schiff base reaction was employed to synthesize two COFs: TAPFy-PhI and TAPB-PhI.
• Characterization included assessment of crystallinity, porosity, chemical stability, band gaps, and light absorption.
• Photocatalytic hydrogen evolution was measured using ascorbic acid as a sacrificial reagent.

Main Results:

• TAPFy-PhI and TAPB-PhI COFs demonstrated high crystallinity, permanent porosity, and excellent chemical stability.
• The synthesized COFs exhibited suitable band gaps and broad visible-light absorption.
• TAPFy-PhI achieved a hydrogen evolution rate of 1763 μmol g⁻¹ h⁻¹, which increased to 2718 μmol g⁻¹ h⁻¹ with 1 wt% Pt co-catalyst.

Conclusions:

• Donor-acceptor COFs incorporating phthalimide are effective photocatalysts for hydrogen evolution.
• The TAPFy-PhI COF shows significant potential for efficient and enhanced hydrogen production.
• Platinum co-catalysis can substantially improve the photocatalytic hydrogen evolution performance of these COFs.