Brown TiO₂-Based Fe-Ni Thiospinel Binary Nanocomposite as a Sustainable Catalyst with Synergistic Improvement Assisted by H₂O₂ and Ascorbic Acid for Round-the-Clock Removal of Rhodamine B

In this work, a novel FeNi2S4/TiO2-x nanocomposite was prepared by facile hydrothermal synthesis, then comprehensively characterized by a multitechnique approach, and subsequently employed for round-the-clock (light and dark) removal of rhodamine B. Superior improvement of the morphological and thermal properties of the FeNi2S4/TiO2-x nanocomposite due to the use of sodium dodecyl sulfate was investigated. An l-ascorbic acid-assisted photo-Fenton catalyst can be employed effectively for complete rhodamine B removal at 30 min using a 10 W white-light-emitting diode (LED) source under a wide range of operating conditions compared to other reported photo-Fenton catalysts. The obtained results show a significant synergism between the nanocomposite components, which makes the total RhB removal much better than when each was used alone. This study presents a facile approach to designing a sustainable multifunctional catalyst with reusability, high catalytic activity, and environmental friendliness. Due to the photocatalytic and photo-Fenton synergism in the presence of hydrogen peroxide and ascorbic acid under visible light, there is high potential to generate more electron/hole carriers and hydroxyl radicals ((OH)-O-center dot).