Phase-Controlled Synthesis of Bismuth oxide Polymorphs towards Removal of Environmental Pollutants

Up to now, TiO2 has been intensely used for environment application particularly in the removal of pollutants’. However, in the past decade, bismuth-based compounds have been much involved for environmental applications.... [ view full abstract ]

Up to now, TiO₂ has been intensely used for environment application particularly in the removal of pollutants’. However, in the past decade, bismuth-based compounds have been much involved for environmental applications. Bismuth oxide (Bi₂O₃) is a p-type semiconductor with unique physicochemical properties in tremendous applications for photovoltaic, sensors, electrochromic and photocatalyst. In common, Bi₂O₃ has six polymorphic forms. Among them, α- Bi₂O₃ is a more stable monoclinic phase at room temperature whereas δ- Bi₂O₃ (face centered cubic) is stable at high temperature. However β (tetragonal), γ (body centered cubic), ε (tetragonal) and ω (triclinic) phases are metastable in nature. In the past few years, several methods are followed regarding the synthesis of stable (α- phase) and metastable (β - phase) Bi₂O₃. In this work, synthesis of stable and metastable Bi₂O₃ (α & β - phase) were considered via post-synthetic thermal decomposition process using bismutite as a precursor. As-synthesized samples are found in different phase which was confirmed by powder X-ray diffraction (XRD) and Raman spectroscopy. Moreover, the morphologies of samples were characterized by field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). Further, the photocatalytic performance of as-synthesized samples will be explored under stimulated solar illumination.