Simultaneous electrochemical upgrading of polyethylene terephthalate plastic and carbon dioxide into valuable chemicals

The natural environment is gravely threatened by plastic made of polyethylene terephthalate (PET) and CO2 pollution, which not only damage the environment but also waste a significant amount of carbon energy. Here, an electrocatalytic waste upgrading method to convert PET waste plastic and CO2 wastes into formate at the anode and cathode simultaneously. The anodic Mn/CoOOH electrocatalyst achieves high Faradaic efficiency (FE) of 96.7 % for formate production via PET hydrolysate oxidation and the cathodic oxygen vacancy rich Bi2O2CO3 (OV-rich BOC) electrocatalyst achieves high FE of 97.5 % for formate production via CO2 reduction. The constructed Mn/CoOOH||OV-rich BOC integrated system gets a total FEformate of 184.6 % at 150 mA cm−2 by combining integrated two half-reactions, along with outstanding stability for 100 h with a cell voltage of 2.2 V. More importantly, the oxidation and reduction intermediate (*CH2OH and *OCHO) were detection by quasi-in-situ electron paramagnetic resonance (EPR) and operando attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), which contribute to the understanding of reaction pathways. Techno-economic analysis shows that the final product potassium diformate can get profit instead of format acid, which points out the direction of practical application. Based on this study, electrocatalytic PET plastic valorization coupled with CO2 reduction can be a practical and cost-effective way to achieve the production of valuable chemicals. [Display omitted] •PET hydrolysate and CO2 are electro-reformed simultaneously to formate.•Mn/CoOOH||OV-rich BOC two-electrode integrated system was constructed.•The constructed system showed excellent stability for at least 100 h at 2.2 V.•The oxidation and reduction intermediate (*CH2OH and *OCHO) were detection by EPR and ATR-FTIR.