Defect-Engineered Microwave-Responsive Ni@C Composites From Waste PET for Catalytic Plastic Upcycling

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Direct catalytic upcycling of robust solid plastic waste faces challenges due to harsh conditions and expensive catalysts.
• Existing methods often lack efficiency and sustainability in plastic conversion.

Purpose of the Study:

• To develop a circular strategy for converting waste poly(ethylene terephthalate) (PET) into a microwave-responsive catalyst.
• To enable efficient microwave-assisted catalytic upcycling of high-density polyethylene (HDPE).

Main Methods:

• Waste PET bottles were converted into a defective Ni@C composite catalyst via microwave-assisted depolymerization and pyrolysis.
• The Ni@C catalyst was used for microwave-assisted peroxymonosulfate (PMS) activation to degrade HDPE.
• Spectroscopic and strain-mapping analyses were employed to understand catalyst properties and reaction mechanisms.

Main Results:

• The Ni@C catalyst, featuring strain-rich Ni-C heterointerfaces, effectively dissipated microwave energy and activated PMS.
• Microwave-thermal-chemical activation efficiently degraded HDPE (up to 96%) through polymer-chain disordering and C-C bond scission.
• The process yielded valuable liquid hydrocarbons and oxygenates with limited phytotoxicity.

Conclusions:

• A circular plastic-to-catalyst-to-product strategy was successfully demonstrated.
• The developed Ni@C catalyst offers an efficient route for plastic waste upcycling using microwave energy.
• This approach integrates waste-derived catalyst design with sustainable plastic conversion for carbon recovery.