Electrocatalytic upgrading of polyethylene terephthalate plastic to formic acid at an industrial-scale current density via Ni-MOF@MnCo-OH catalyst

Electrocatalytic polyethylene terephthalate (PET) waste upgrading is crucial for developing a circular plastics economy and solving the energy crisis, but achieving efficient PET upgrading at an industrial-scale current density remains a formidable challenge. In our work, Ni-MOF@MnCo-OH catalyst was prepared by designing hierarchical heterostructure and incorporating the concept of multi-metal sites, wherein the Ni-MOF can be derived from PET plastic. Benefiting from the advantages of material design, the catalyst demonstrates excellent adsorption capabilities for both OHad and ethylene glycol (EG), while also enhancing the electron transfer capability of Ni-MOF. We achieve a high Faradaic efficiency (∼80 %) during PET plastic upgrading at industrial-scale current density (300 mA·cm−2 at 1.43 V vs. RHE) with Ni-MOF@MnCo-OH. Moreover, through theoretical calculations and in situ Fourier transform infrared (FTIR) spectroscopy, we have further elucidated the mechanism of ethylene glycol oxidation reaction (EGOR). Notably, glycolic acid has been identified as a vital intermediate during the electrical oxidation of EG. This work provides a viable and eco-friendly approach to enhance the value of PET waste through sustainable means.