Photoreforming of poly(ethylene-terephthalate) plastic into valuable chemicals and hydrogen over BiVO4/MoOx: Synergistic promotion of oxidation and reduction processes

Photoreforming plastic waste into value-added chemicals along with hydrogen evolution is crucial for the circular economy, but its efficiency is limited by mutual constraints between proton reduction and plastic oxidation. Herein, MoOx particles were decorated onto BiVO4 attempting to promote photo-redox reactions, simultaneously. Experiments and theoretical calculations demonstrate that oxygen vacancy in MoOx promotes the adsorption of pretreated poly(ethylene-terephthalate), leading to enhanced oxidation of poly(ethylene-terephthalate). Meanwhile, MoOx boosts the transfer of photoelectrons from BiVO4 to MoOx by Mo5+/6+ ions with variable valence states and lowers the free energy of H+ + e– → H* from 0.39 to –0.12 eV, thereby promoting H2 evolution. Consequently, the photoreforming efficiencies of converting poly(ethylene-terephthalate) into formate, acetate and H2 by BiVO4/MoOx are 0.29, 0.19 and 1.96 mmol g–1 h–1, which are respectively 6.2, 6.0 and 5.9 times higher than that by BiVO4. This work presents avenues for designing high-performance catalysts to efficiently photo-reform plastic.