Selective Oxidation of Polyesters via PdCu-TiO₂ Photocatalysts in Flow

Area of Science:

• Materials Science and Engineering
• Catalysis
• Environmental Chemistry

Background:

• Plastic waste, particularly polyethylene terephthalate (PET), poses a significant environmental challenge.
• Catalytic upcycling offers a sustainable route for plastic waste management and a circular economy.
• Developing efficient and selective conversion methods under mild conditions is crucial for reducing energy consumption and carbon footprint.

Purpose of the Study:

• To develop a highly selective and efficient photocatalyst for the conversion of PET plastic waste.
• To investigate the catalytic performance of a modified TiO2 photocatalyst under ambient conditions.
• To explore the synergistic effects of atomic palladium and metallic palladium-copper on photocatalytic activity and selectivity.

Main Methods:

• Fabrication of a TiO2 photocatalyst modified with atomic palladium (Pd) and metallic palladium-copper (PdCu) nanoparticles (Pd1Cu0.4-TiO2).
• Selective, aerobic conversion of PET in a flow reactor under ambient conditions using the engineered photocatalyst.
• Analysis of reaction products, including formate evolution and selectivity, and comparison with existing photocatalytic systems.

Main Results:

• The atomically synergistic Pd1Cu0.4-TiO2 catalyst achieved a high formate evolution rate of 4707 μmol g-1 h-1 with 92.3% selectivity.
• The catalyst demonstrated 10-1000 times greater activity compared to previously reported photocatalytic systems for PET conversion.
• Synergy between atomic Pd and PdCu enhanced charge transfer, promoted oxygen-induced C-C bond cleavage, and suppressed product decomposition.

Conclusions:

• Photocatalytic conversion of waste plastic into valuable chemicals is a sustainable approach.
• Targeted engineering of atomically synergistic catalysts and reaction systems is key to achieving efficient plastic upcycling.
• The developed Pd1Cu0.4-TiO2 catalyst represents a significant advancement in sustainable plastic waste valorization.