Engineering Microporous Zn-Functionalized Carbon Catalysts for Controllable Chain Cracking and Aromatization in...

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Conventional plastic upcycling methods face challenges like high costs, rapid catalyst deactivation, and excessive product cracking.
• Developing efficient and selective catalytic systems is crucial for polyolefin waste valorization.

Purpose of the Study:

• To introduce a novel, noble-metal-free catalytic strategy for the selective upcycling of polyethylene (PE).
• To achieve high yields of valuable products like n-paraffins and light aromatics from PE waste.

Main Methods:

• Engineered Zn-decorated microporous carbon with oxygenated groups and Brønsted acid sites.
• Utilized a decomposition-catalysis cascade strategy for controlled PE conversion.
• Employed in situ Fourier transform infrared (FTIR) spectroscopy to elucidate reaction mechanisms.

Main Results:

• Achieved a high liquid yield of 50.50 wt % and >75 mol % carbon selectivity for n-paraffins and aromatics.
• Discovered a novel carbenium ion anchoring mechanism stabilizing intermediates for precise chain-cracking and isomerization.
• Demonstrated the catalyst's robustness and efficiency in converting real-life PE waste.

Conclusions:

• The developed catalytic system offers a scalable, controllable, and cost-effective route for chemical upcycling of polyolefins.
• This approach supports a circular economy framework by transforming plastic waste into high-value chemicals.
• The insights into the reaction mechanism provide a foundation for designing advanced catalysts for plastic valorization.