Preparation Of Bismuth Oxide Composite Material For Efficient Photocatalysis

With the development of society and economy, environmental pollution problems become more serious. In recent years, due to the wide range of applications in environmental pollution control, particularly in the field of wastewater treatment, semiconductor photocatalytic technology attracts more and more attention. Because of its excellent properties in band gap, refractive index and permittivity, Bi2O3 has been one of the most popular materials for semiconductor photocatalysis. However, in the photocatalytic process, the photo-generated carriers recombine quickly, which seriously affects the photocatalytic performance of Bi2O3. Therefore, Bi2O3 composites have become one of the hot spots to improve the photocatalytic properties. In this work, Bi2O3 was synthesized by co-precipitation method and F-TiO2 and Ag2O were incorporated into Bi2O3 to form Bi2O3/F-TiO2 and Bi2O3/Ag2O composites, which suppress the recombination of photo-generated carriers and thus improve the photocatalytic performance. The main contents are as follows:1. Bi2O3 was prepared via co-precipitation method by adding ammonia in the precursor, and then calcining the precipitation. The effect of calcination temperature on the photocatalytic performance was studied. The results show that:(1) the calcination temperature has an important influence on the photocatalytic performance of Bi2O3; (2) when the calcination temperature is 400 ℃, Bi2O3 exhibits the best visible light photocatalytic performance with a maximum Methyl Orange (MO) degradation rate of 80% for 180 min; (3) the superior photocatalytic performance should be attributed to its good light adsorption and low photoelectron-hole recombination.2. Bi2O3/F-TiO2 composites were successfully synthesized via an aqueous precipitation method and their photocatalytic performances under visible light irradiation were investigated. The results shows that:(1) Bi2O3/F-TiO2 composites exhibit a better photocatalytic performance than pure Bi2O3; (2) their photocatalytic performance is dependent on the proportion of F-TiO2 in the composites; (2) the Bi2O3/F-TiO2 composite with 12 wt.%F-TiO2 achieves a highest MO degradation rate of 95% for 180 min; (3) the enhanced photocatalytic performance is mainly ascribed to the increase in light absorption and the reduction in photoelectron-hole pair recombination in Bi2O3 with the introduction of F-TiO2.3. Bi2O3/Ag2O photocatalysts were successfully synthesized via the co-precipitation method and their photocatalytic performances under visible light irradiation were investigated. The results indicate that (1) Bi2O3/Ag2O photocatalysts exhibit a better photocatalytic performance than pure Bi2O3; (2) the photocatalytic performance of Bi2O3/Ag2O photocatalysts is dependent on the proportion of Ag2O and when the amount of AgNO3 in precursor is 0.03mol, Bi2O3/Ag2O achieves a highest MO degradation rate of 91% for 60 min; (3) the enhanced photocatalytic performance is ascribed to the increase in the light adsorption and the reduction in the photoelectron-hole pair recombination in Bi2O3 with the introduction of Ag2O.