Preparation and Characterization of Sb 2 S 3 –TiO 2 Nanocomposite for the Enhanced Photocatalytic Degradation and Mineralization of Azo Dye

Abstract

Abstract

Sb₂S₃–TiO₂ semiconductors heterojunction promote separation of electron–hole charges generated upon light irradiation. This enhancement in charge separation depends on the quality of interfacial contact between Sb₂S₃ and TiO₂, their composition, and their morphological and surface properties. In this study, the Sb₂S₃–TiO₂ nanocomposites were synthesized by two different methods (hydrothermal and mechanical mixing methods) with different percent compositions (5–20% of Sb₂S₃) and different calcination temperatures (200–600°C) to study their effects on improving the interfacial contact between both semiconductors. Among all synthesized samples, hydrothermally synthesized 10% Sb₂S₃–TiO₂ nanocomposite calcined at 300°C showed the highest photocatalytic degradation of methyl orange (MO) dye solution. X-ray powder diffraction pattern showed that the anatase phase of TiO₂ and the orthorhombic phase of Sb₂S₃ are retained in the nanocomposite. Scanning electron microscopy and energy-dispersive X-ray revealed formation of nanocomposite with purity. Transmission electron microscopy revealed that TiO₂ is deposited better on Sb₂S₃ in hydrothermally synthesized nanocomposite than in mechanically mixed composite. However, 300°C calcinations of the composite helped improve the interaction between TiO₂ and Sb₂S₃. Brunauer-Emmett-Teller (BET) surface area analysis showed the highest specific surface area for the hydrothermally synthesized 10% Sb₂S₃–TiO₂ nanocomposite calcined at 300°C. Considering all results, a reasonable mechanism of photocatalysis of Sb₂S₃–TiO₂ nanocomposite has been proposed. Furthermore, the chemical oxygen demand data showed substantial mineralization of MO dye by the 10% Sb₂S₃–TiO₂ nanocomposite calcined at 300°C.