Microwave-initiated MAX Ti3AlC2-catalyzed upcycling of polyolefin plastic wastes: Selective conversion to hydrogen and carbon nanofibers for sodium-ion battery

Waste polyolefins, accounting for over half of all plastic wastes, represent a largely untapped resource. Efficiently upcycling polyolefin wastes into value-added resources by catalysis is both economically and environmentally sustainable but rather challenging due to lacking of highly selective catalysts and viable utilization of upcycled products. Herein, MAX (Ti3AlC2) is employed as both microwave-susceptor and catalyst to promote deconstruction of polyethylene (LDPE and HDPE) and polypropylene (PP) into highly pure hydrogen and graphitic nanofibers for Na ion battery. The hydrogen production selectivity of 75 vol % (LDPE), 78 vol% (HDPE) and 78 vol% (PP) are all the highest among reported methods. More importantly, carbon-nanofibers are obtained with high graphitization degree, empowering their application in Na-ion battery as anode electrode materials with good rate capability and stable cycling performance (2000 cycles). Our results demonstrate MAX Ti3AlC2 as a promising microwave-susceptible catalyst and find new applications in energy storage for plastic waste-upcycled resources. [Display omitted] •Waste face masks, plastic wraps and shopping bags are efficiently upcycled.•The H2 selectivity of PP, LDPE and HDPE ranks ahead of reported methods.•Carbon-nanofibers are obtained with high graphitization degree and selectivity.•CNFs as anode electrode material in Na ion battery show stable cycling performance.