For the experiment with real-world waste PET plastic derived EG, a commercial sparkling water PET bottle (Highland Spring, sourced from Sainsbury's UK) was pre-treated with alkaline pre-treatment. The bottle was cut in small pieces, dipped in liquid N2 and then pulverized in a grinder. 1 M aqueous KOH was then added (PET concentration 50 mg mL -1 ) and the solution was heated at 80 ºC for 5 days under continuous stirring. The solution was then filtered to remove PET fragments and the clear solution was directly used as anolyte for the PEC experiments. The concentration of EG after pre-treatment was determined as 10.3±2.8 mg mL -1 (~0.2 M) by HPLC.