The role of tin species in doped iron (III) oxide for photocatalytic degradation of methyl orange dye under UV light.

Iron (III) oxide, a stable semiconductor with versatile applications, was synthesized alongside Sn-doped FeO (Sn-FeO) using the sol-gel technique. Characterization via X-ray diffraction, field-emission scanning electron microscopy, and UV-visible spectroscopy confirmed the presence of α- and γ-Fe2O3 phases in the synthesized powders. Incorporation of the dopant reduced the initial band gap energy of FeO (2.2 eV) by approximately 0.1 eV. To evaluate photocatalytic performance, FeO and Sn-FeO were tested for decolorization efficiency of a methyl orange solution. Results revealed the 5 wt% Sn-doped catalyst as optimal, achieving complete degradation of methyl orange within 120 min under simulated solar light. The addition of small amounts of Sn effectively reduced the FeO band gap and significantly enhanced photocatalytic performance. Investigation of pH and dye concentration impact on photocatalytic degradation revealed superior activity under acidic conditions compared to alkaline. Furthermore, maintaining a moderate concentration of methyl orange (10 ppm) ensured optimum photocatalytic activity.