Visible light photocatalytic decomposition of organic dye and biodegradation-resistant antibiotic pollutants using cerium-doped tungsten trioxide nanoparticles

Ce-doped WO₃ nanoparticles were fabricated and characterized using powder X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Raman, SEM–EDX, UV–Vis, photoluminescence (PL), dynamic light scattering (DLS), and X-ray photoelectron spectroscopy (XPS) analyses. The results revealed the formation of a highly crystalline monoclinic phase in Ce-doped WO₃ photocatalyst (abbreviated WCC), confirmed by Raman spectroscopy. The bandgap was tuned by increasing the percentage of Ce dopant, where the WCC (1 mol wt% Ce-doped WO₃) photocatalyst sample exhibited the highest photocatalytic activity towards synthetic methylene blue (MB) dye pollutant and biodegradation-resistant tetracycline hydrochloride (TC-HCl) antibiotic. The decomposition efficiency using the WCC photocatalyst against aqueous MB dye and TC-HCl antibiotic reached 95% and 51% after exposure to simulated sunlight irradiation for 180 min, with excellent stability after four recycling runs. The interfacial contact between Ce and WO₃ effectively shortened the charge transfer carrier process, enabling redox reactions to provide the best decomposition efficiency over the investigated pollutants. The photodecomposition rate constant of WCC was 0.017 min⁻¹ for MB dye, which is 3.6-fold higher performance than common literature photocatalysts. The results showed the significance of the environmental impact toxicity assessment by applying the treated water to finger millet plant growth. Based on the research feasibility, the synthesized photocatalyst demonstrated superior decomposition against dyes and antibiotics, making it highly suitable for applications in wastewater treatment. Moreover, the use of degraded water resulted in productive plant growth.