The Fabrication of Halogen-Doped FeWO Heterostructure Anchored over Graphene Oxide Nanosheets for the Sunlight-Driven Photocatalytic Degradation of Methylene Blue Dye.

Rapid industrialization and urbanization are the two significant issues causing environmental pollution. The polluted water from various industries contains refractory organic materials such as dyes. Heterogeneous photocatalysis using semiconductor metal oxides is an effective remediation technique for wastewater treatment. In this research, we used a co-precipitation-assisted hydrothermal method to synthesize a novel I-FeWO/GO sunlight-active nanocomposite. Introducing dopant reductive iodine species improved the catalytic activity of FeWO/GO. I ions improved the catalytic performance of HO by doping into FeWO/GO composite. Due to I doping and the introduction of graphene as a support medium, enhanced charge separation and transfer were observed, which is crucial for efficient heterogeneous surface reactions. Various techniques, like FTIR, SEM-EDX, XRD, and UV-Vis spectroscopy, were used to characterize composites. The Tauc plot method was used to calculate pristine and iodine-doped FeWO/GO bandgap. Iodine doping reduced the bandgap from 2.8 eV to 2.6 eV. The degradation of methylene blue (MB) was evaluated by optimizing various parameters like catalyst concentration, oxidant dose, pH, and time. The optimum conditions for photocatalysts where maximum degradation occurred were pH = 7 for both FeWO/GO and I-FeWO/GO; oxidant dose = 9 mM and 7 mM for FeWO/GO and I-FeWO/GO; and catalyst concentration = 30 mg and 35 mg/100 mL for FeWO/GO and I-FeWO/GO; the optimum time was 120 min. Under these optimum conditions, FeWO/GO and I-FeWO/GO showed 92.0% and 97.0% degradation of MB dye.