Silver-and-Sulphur-Codoped Fe3O4/TiO2 as a Magnetically Separable Photocatalyst for Methylene Blue Degradation under Visible Light

Abstract

This research aimed to investigate how the addition of silver and sulphur dopants modified the TiO₂ photocatalyst to enhance its responsiveness to visible light and improve its photocatalytic activity for methylene blue degradation. In addition, Fe₃O₄ was also added as a core to add magnetic properties to the photocatalyst material. The Fe₃O₄/TiO₂-Ag/S materials were prepared using FeCl₃.6H₂O and FeSO₄.7H₂O as the magnetite precursors, titanium tetraisopropoxide (TTIP) as the TiO₂ precursor, while AgNO₃ and CH₄N₂S were used as the sources for silver and sulphur dopants, respectively. The synthesized materials were next characterized using FT-IR, XRD, UV-Vis spectrophotometer, SEM-EDX, TEM, and VSM. The activity of the photocatalyst was then assessed through methylene blue degradation in a closed reactor involving various contained Ag:S ratios and reusability examination. The evaluation of photocatalytic degradation results was performed using UV-Vis spectrophotometry. Afterwards, the research findings indicate that the Fe₃O₄/TiO₂-Ag/S was successfully synthesized and exhibited magnetic properties with a saturation magnetization value of 5.33 emu/g. The highest photocatalytic activity (98.21%) was observed in Fe₃O₄/TiO₂-Ag/S (1:1) with a band gap energy value of 2.64 eV under visible light exposure at pH 10, 120 min, 10 mg mass of the photocatalyst, and methylene blue concentration of 5 mgL^-1. Furthermore, the Fe₃O₄/TiO₂-Ag/S photocatalyst was known to perform good stability through four reuse cycles.