Electrochemical upgrading of PET plastic wastes for hydrogen production using porous Fe–Ni2P nanosheets

The electrochemical upgrading of PET plastic wastes-to-hydrogen is an important conversion system for achieving sustainable, low-cost and scalable hydrogen production. Designing cost-effective and highly active dual-function electrocatalysts for the ethylene glycol (PET monomer) oxidation reaction (EGOR) and hydrogen evolution reaction (HER) is very crucial for achieving practical application of PET plastic wastes upgrading assisted electrochemical water splitting technology. Herein, a simple hydrothermal-phosphating two-step method is implemented to achieve ultrathin porous iron (Fe) doped nickel phosphide (Ni₂P) nanosheets attached to the nickel foam (named as Fe–Ni₂P/NF). Profiting from the ample active sites provided by the ultrathin structure, porous structure and the optimized electronic structure caused by Fe doping, Fe–Ni₂P/NF exhibits predominant electroactivity for HER and EGOR. Additionally, PET plastic wastes hydrolysate electrolyzer is assembled by using Fe–Ni₂P/NF as a dual-functional electrode for the co-generation of hydrogen and formate. The constructed Fe–Ni₂P/NF||Fe–Ni₂P/NF electrolyzer only requires an electrolysis potential of 1.39 V to derive 10 mA cm⁻² current density, which is lower than that of conventional water splitting (1.55 V). This work would afford a reference for constructing cost-efficient and steady plastic-assisted water electrolysis bifunctional catalysts, and expands the field of energy-saving co-generation of value-added chemicals and hydrogen.