氧化铋/硅藻土复合光催化剂的制备及其可见光催化性能

Preparation and Visible-light Photocatalytic Properties of Bi_2O_3/Diatomite Composite Photocatalyst

将硅藻土分散在硝酸铋溶液中,经冷冻干燥后于空气中煅烧得到了Bi2O3/硅藻土质量比为0.10:1.00～0.60:1.00的一系列复合光催化剂。用X射线粉末衍射、场发射扫描电子显微镜、比表面积及孔径分析仪对所制备的产物进行了结构表征。以500W氙灯为光源,亚甲基蓝为模拟污水中有机染料,评价了复合光催化剂的可见光催化性能。结果表明:晶粒尺寸约31.7nm的Bi2O3较好地分散在硅藻土表面,既保留了硅藻土自身的多孔结构,又发挥了Bi2O3的可见光催化性能。负载Bi2O3的复合光催化剂能吸收波长小于520nm的可见光和紫外光,Bi2O3/硅藻土质量比为0.40:1.00时,氙灯光照2h能将20mg/L的亚甲基蓝溶液降解90%以上。

Bi2O3/diatomite composite photocatalysts in a mass ratio of Bi2O3 to diatomite range from 0.10：1.00 to 0.60：1.00 were prepared via freeze-drying and subsequent calcination in air. The as-prepared Bi2O3/diatomite composite photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscope and N2 adsorption-desorption measurement as well. The photocatalytic properties of the samples were investigated through the photocatalytic degradation of methylene blue （MB） under visible light irradiation using a 500 W Xe lamp. The results show that the Bi2O3 nanoparticles with the particle size of 31.7 nm can be well dispersed on the diatomite surface. With the porous structure of diatomite and the photocalalytic properties of Bi2O3, the Bi2O3/diatomite composite photocatalysts gave a better photocalalytic property under visible light irradiation, and the degradation rate of MB （20 mg/L） reached 〉 90% after 2 h visible light irradiation over the composite Bi2O3/diatomite of 0.40：1.00 （in mass ratio）.