Sustainable solar-and electro-driven production of high concentration H2O2 coupled to electrocatalytic upcycling of polyethylene terephthalate plastic waste

Abstract

The photoelectro-reforming of poly (ethylene terephthalate) (PET) waste coupled with the synthesis of hydrogen peroxide (H2O2) poses significant implications for environmental and energy engineering, yet it presents substantial with challenges. A strategy offering an energy efficient photo-electrolysis is reported, which couples oxygen reduction reaction (ORR) with oxidation reaction of PET hydrolysate (glycol, EGOR), utilizating a porous hollow double-shell with oxygen vacancies Z-scheme Mo2N-Co3O4@Fe2O3/PVDF/NF cathode and a Co3O4/NF anode within a cell electrolyser. The H2O2 concentration by hydrophobic photocathode (3.4 wt%) significantly surpasses that of hydrophilic electrode (1.9 wt%), attributing to the hydrophobic modified enhances the mass transfer and utilization efficiency of O2. The Mo2N-Co3O4@Fe2O3 has photothermal effect by introducing Mo2N with local surface plasmon resonance (LSPR) for the direct synthesis of high concentration H2O2 (21.4 wt%). The photoelectro-reforming of PET by photoanode yields the value-added products such as terephthalic acid (PTA) and potassium diformate (KDF) with a high Faradic efffciency (89 %). Notably, EGOR assistes the ORR, resulting in a yield of H2O2 by ORR that is significantly improved at least three times in comparison to the water oxidation reaction coordinated with ORR. This research contributes to a feasible methodology for H2O2 production, and the transformation of plastics and other waste materials into value-added chemicals.