Boosting upcycling polypropylene waste to propylene via microwave catalysis

Polypropylene waste presents both an environmental challenge and a valuable resource for sustainable chemical production. This study presents a direct microwave catalytic upcycling process using a Ru/α-Fe₂O₃ catalyst to efficiently convert polypropylene back into propylene, achieving a propylene yield of 57.2 wt% at 400 °C, which is the highest yield reported in literature. The recovered propylene can re-enter PP production or serve as a petrochemical feedstock, promoting circular economy goals. DFT calculations were conducted to elucidate catalytic behavior of Fe-O and Ru-O active sites in activation of C-H and C-C bonds. Microwave irradiation enhances reaction selectivity by rapidly and selectively energizing the catalyst. The catalyst exhibits stable performance over multiple reaction cycles under microwave conditions. This work provides a transformative strategy for converting plastic waste into valuable resources, driving sustainable advancements in polymer upcycling.