Photocatalytic and Radiation-Optical Properties of Bismuth Silicate Synthesized by the Microwave Method

A hydrothermal–microwave method has been developed for the synthesis of bismuth metasilicate from water-soluble bismuth compounds and sodium silicate. The bismuth silicate obtained in the form of a nanodispersed powder exhibits high photocatalytic activity and radiation resistance. The characteristics of the synthesized bismuth silicate were determined using differential thermal analysis, X-ray phase analysis, UV–VIS, and IR spectroscopy. In the temperature range of 600–800°C, crystalline phases of bismuth silicates with compositions Bi2SiO5, Bi4Si2O12, and Bi2SiO20 are formed. The photocatalytic activity of the samples was studied in the degradation reaction of methylene blue under UV irradiation. Physicochemical studies have shown that the synthesized bismuth silicate is a promising material for various applications as a wide-bandgap semiconductor, photocatalyst, and radiation shielding material. The conducted research demonstrates the efficiency of microwave synthesis of bismuth silicates: the synthesis and heat-treatment times are reduced (by 3–5 times), and energy consumption is lowered (by 70–80%) compared to conventional synthesis methods.