Reversible Supramolecular Hydrogel for Air-Tolerant Photon Upconversion: Key Development for Photocatalyst Recovery...

Area of Science:

• Supramolecular Chemistry
• Photocatalysis
• Materials Science

Background:

• Upconversion hydrogels are challenging to develop for aqueous, aerobic conditions, especially for component recovery.
• Existing systems often lack reusability and simple product extraction methods.

Purpose of the Study:

• To create the first supramolecular photocatalytic hydrogel for green-to-blue triplet-triplet annihilation upconversion (TTA-UC) in aerated water.
• To enable in situ photochemical reactions with reversible gel disassembly for product and catalyst recovery.

Main Methods:

• Coassembly of a low-molecular-weight gelator (LMWG), surfactant, and a sensitizer/emitter pair (PtOEP/DPAS).
• Formation of nanostructured compartments to protect triplet states from oxygen.
• Reversible gelation for in situ reactions and post-reaction disassembly.

Main Results:

• Achieved green-to-blue TTA-UC in aerated water using a supramolecular hydrogel.
• Demonstrated reversible gelation, enabling in situ reactions and facile product extraction without heat.
• Recovered up to 77% of the platinum-based sensitizer from the gel matrix.

Conclusions:

• The developed supramolecular hydrogel is a modular and recyclable platform for photochemical transformations.
• Offers advantages in reusability, extractability, and operational simplicity over previous air-stable upconversion hydrogels.
• Provides a mild and environmentally friendly approach to photocatalysis.