Energy‐Saving Microwave‐Assisted Catalysis Over SiC@NiFe for Selective Valorization of Plastic Wastes Into H ₂ and Carbon Nanotubes

Plastic wastes impose a significant environmental burden, yet chemically recycling them into valuable feedstocks remains presenting huge challenges. Herein, an energy-saving microwave-assisted catalysis system is reported via interfacial engineering of the catalyst layer on the microwave absorber for selective valorization of plastic wastes into hydrogen (H₂) and carbon nanotubes (CNTs). As proof of concept, a NiFe alloy layer coated on a microporous SiC foam (SiC@NiFe) is fabricated. The unique architecture enables directional thermal transfer from SiC to NiFe, minimizing energy losses from disordered thermal dissipation while preventing undesired contact of plastic-SiC, thereby enhancing energy utilization efficiency and suppressing side reactions, respectively. Moreover, the increased inside pressure generated during plastic decomposition creates a favorable pressure gradient, driving efficient mass transfer into the microporous foam. Accordingly, the confined intermediates undergo sufficient contact with the NiFe catalytic layer. The resultant SiC@NiFe delivered H₂ yield of 67 mmol g_plastic ^-1 with selectivity of 96 vol.% at 450 °C in upcycling of low-density polyethylene (LDPE). This work presents a viable strategy for plastic waste valorization with the advantages of high efficiency and energy-saving operation, provides valuable perspectives on addressing white pollution within the framework of the circular economy.