Photoelectrochemical conversion of plastic waste into high-value chemicals coupling hydrogen production

There is no satisfactory treatment technology for plastic waste, which has been a global challenge so far. Here, we report a photoelectrochemical approach for efficient valorization of waste polyethylene terephthalate (PET) plastic to produce formate coupled with green hydrogen production. Due to the cocatalytic effect of nickel phosphate (Ni-Pi) on α-Fe2O3 photoanode, the Faradaic efficiency of PET hydrolysate solution to formate reached as high as 87% in aqueous electrolyte without any additional oxidant. In addition, an integrated PET oxidation-hydrogen production system achieved a photocurrent density of 1.5 mA/cm2 at a cell voltage of 1.1 V, which is 270 mV lower than the conventional water splitting. Furthermore, we also demonstrate that high selective formate production was also applicable to real-world waste PET plastic. This work provides a sustainable paradigm on photoelectrochemical strategy to upcycle waste PET plastic into value-added chemicals and green hydrogen.