Bi2O3-BiFeO3 Glass-Ceramic: Controllable β/γ-Bi2O3 Transformation and Application as Magnetic Solar-Driven Photocatalyst for Water Decontamination

Glass and glass-ceramic materials containing photoactive and magnetic crystalline phases were prepared from Fe2O3 and Bi2O3 using the conventional melt method. All samples were characterized in terms of formed phases, morphological analyses, optical properties, and magnetic properties. Formation of the photoactive tetragonal beta- and body-centered cubic gamma-Bi2O3 phases along with the magnetic BiFeO3 and Fe2O3 phases was revealed. However, the crystalline structure relied on the composition and the applied heat-treatment time. beta-/gamma-Bi2O3 transformation could be controlled by the heat-treatment time. The samples exhibited variable magnetic properties depending on their composition. All of the samples showed excellent absorbance in visible light with an optical band gap of 1.90-2.22 eV, making them ideal for solar-light-driven photocatalysis. The best performance was recorded for the sample containing equal amounts of Fe2O3 and Bi2O3 due to the formation of gamma-Bi2O3/BiFeO3 heterojunction in this sample.