High-gravity-assisted synthesis of NiCo2O4/C for electro-upcycling polyethylene terephthalate to commodity chemicals

Regarding the environmental and ecological hazards of waste plastics, the unexploited polyester resources promise to produce valuable chemicals and fuels by electrocatalytic upcycling in combination with alkaline hydrolysis. Herein, we propose a universal approach to synthesize carbon supported NiCo 2 O 4 nanoparticles (NPs) utilizing high gravity technology combined with heat treatment for electrocatalytic valorization of polyethylene terephthalate (PET). This route enables instantaneous and continuous precipitation of the composites including Co-NH 3 complex and Ni hydroxide on carbon in a rotating packed bed (RPB) reactor, and achieves ultrasmall and ligand-free NiCo 2 O 4 NPs (6 nm) with significantly improved dispersity after heat treatment. The as-prepared NiCo 2 O 4 NPs/C converts PET-derived EG to formate with a promising faradaic efficiency (FE) of over 90 % and a high productivity of about 4.5 mmol·cm −2 ·h −1 at 1.5 V (vs RHE). Furthermore, this strategy can also be extended to the preparation of other supported ternary oxide NPs for efficient electro-oxidation of PET hydrolysate.