Multi-scale Designed Co_xMn_3–xO₄ Spinels: Smart Pre-Catalysts towards High-Efficiency Pyrolysis-Catalysis Recycling of Waste Plastics

In this work, multiscale designed 3-dimensional (3D) rose-like Co_xMn_3–xO₄ spinel smart pre-catalysts that can self-convert into the targeted active site-rich Co/MnO catalysts were developed for the high-efficiency conversion of waste plastics. At a pre-catalyst to plastic weight ratio of 1:14, the carbon nanotube composites (CNCs) and H₂ yield can reach 41 wt% and 36 mmol⋅g^{− 1}_pla., while the specific CNCs and H₂ yield can be as high as 7.48 g^{− 1}_cat. and 634 mmol⋅g^{− 1}_pla.⋅g^{− 1}_cat. The latter is more than one order of magnitude higher than reported in the literature. Density functional theory calculations indicate that the Co/MnO catalyst exhibits excellent activity in the dissociation of alkanes (e.g., CH₄). The resulting CNCs demonstrated excellent discharge capability and extended cycling performance when used as a lithium-ion battery anode. This work revealed an innovative recipe and novel insight for developing advanced catalyst materials as the next generation catalysts for the conversion of waste plastics.