Trash to treasure: electrocatalytic upcycling of polyethylene terephthalate (PET) microplastic to value-added products by Mn0.1Ni0.9Co2O4-δ RSFs spinel

Microplastic pollution has emerged as a pressing environmental issue of global concern due to its detrimental effects on the environment and ecology. Restricted to their characters of complex composition, it is a great challenge to propose a more cost-effective approach to achieve highly selective conversion of microplastic into add-value products. Here we demonstrate an upcycling strategy for converting PET microplastics into added-value chemicals (formate, terephthalic acid and K 2 SO 4 ). PET is initially hydrolyzed in KOH solution to produce terephthalic acid and ethylene glycol , which is subsequently used as an electrolyte to produce formate at the anode. Meanwhile, the cathode undergoes hydrogen evolution reaction to produce H 2 . Preliminary techno-economic analysis suggests that this strategy has certain economic feasibility and a novel Mn 0.1 Ni 0.9 Co 2 O 4-δ rod-shaped fiber (RSFs) catalyst we synthesized can achieve high Faradaic efficiency (> 95%) at 1.42 V vs. RHE with optimistic formate productivity. The high catalytic performance can be attributed to the doping of Mn changing the electronic structure and reducing the metal-oxygen covalency of NiCo 2 O 4 , reducing the lattice oxygen oxidation in spinel oxide OER electrocatalysts . This work not only put forward an electrocatalytic strategy for PET microplastic upcycling but also guides the design of electrocatalysts with excellent performance.