Photocatalytic Upcycling of Poly(ethylene terephthalate) into Hydrogen and Value-Added Products Catalyzed by the NiFe2O4/Bi2WO6 Composite: From Waste to Fuel

Abstract Addressing the towering challenges of plastic waste accumulation necessitates innovative strategies that concurrently alleviate environmental burdens and advance sustainable energy solutions. Herein, we present a photocatalytic upcycling approach in which poly(ethylene terephthalate) (PET) plastic was photoreformed to yield hydrogen (H2) fuel and value-added chemicals catalyzed by a NiFe2O4/Bi2WO6 (NFO/BWO) composite. UV−vis diffuse reflectance spectroscopy demonstrated that incorporation of NiFe2O4 tremendously prolonged the light absorption capability. The NFO/BWO exhibited remarkable photoelectrochemical performance, achieving a low charge transfer resistance of 60.73 Ω and a high photocurrent density of 0.92 μA cm−2. Under visible light, the 10 wt % NFO/BWO photocatalyst manifested outstanding photoreforming activity, yielding 149.6 μmol g−1 of H2 within 4 h from a PET feedstock. The NFO/BWO also achieved a H2 yield of 102.7 μmol g−1 over the same period when employing the actual PET bottle, witnessing its practical viability. Concurrently, PET was oxidized into value-added chemical products, including glycolic acid, formate, and acetate as verified by 1H NMR analysis. Notably, computational frontier molecular orbital analyses further elucidated the dynamics of electron transfer, reinforcing the robustness of the observed redox processes. The dual-functionality approach exemplifies circular economy by coupling waste valorization with sustainable energy generation, thereby maximizing resource efficiency. The findings underscored an effective pathway for plastic pollution mitigation, clean energy production, and sustainable resource recovery.