Balancing polyolefins waste and CO₂ upcycling via microwave-stimulated oxygen dynamics

Polyolefin waste and CO₂ are among the most pressing sustainability issues. Microwave catalysis offers a promising platform for co-converting polyolefin waste and CO₂ into light olefins and syngas. Here, a 40 wt% CeO₂/α-Fe₂O₃ catalyst enables a balanced coupling of polyolefin cracking and CO₂ reforming at 400 °C under microwave irradiation, achieving 36.5 mol% CO₂ conversion, ~70 wt% gas yield, and 57.7 mol% light olefin selectivity. This performance arises from microwave-stimulated oxygen dynamics, wherein CeO₂ activates CO₂ and mitigates carbon deposition via lattice oxygen cycling, while α-Fe₂O₃ promotes selective hydrocarbon cracking and serves as a microwave susceptor. Mechanistic studies and DFT calculations confirm that microwave fields enhance lattice oxygen mobility, direct product selectivity, and sustain catalyst stability. Techno-economic analysis yields a net present value of +36.74 MM USD, and life-cycle assessment reveals a GHG footprint of 0.0667 kg CO₂-eq/kg product-substantially lower than conventional steam cracking routes.