AgVO_3/BiVO_4复合光催化剂的制备及可见光催化性能

Synthesis and Efficient Visible Light Photocatalytic Activity of AgVO_3/BiVO_4 Composite Photocatalysts

通过水热法制备了不同复合比例的AgVO_3/BiVO_4复合型光催化剂,以有机染料甲基橙作为目标降解物评价了其光催化活性,并通过X射线衍射、扫描电子显微镜、X射线能谱、X射线光电子能谱和紫外–可见漫反射光谱对其进行了表征。结果表明:制备的样品纯度很高,复合AgVO3后,BiVO_4的晶体结构未发生改变,但形貌由石笼状变为分散的粒状混合体,光吸收性能增强,同时,二者形成了异质结结构,进一步促进了光生电子-空穴的分离,从而提高了光催化活性。当AgVO_3与BiVO_4的摩尔比为70%时,光催化活性最高且稳定性良好,光照50min对甲基橙降解率高达96.7%,较纯BiVO_4提高约86.5%,且该体系中的主要活性氧物质为空穴。

AgVO3/BiVO4 composite photocatalysts were prepared by a hydrothermal method. The photocatalytic activities of the synthesized samples were evaluated by the degradation of methyl orange. And the samples were analyzed by X-ray diffraction, scanning electron microscopy, X-ray energy spectroscopy, X-ray photoelectron spectroscopy and UV-visible diffuse reflectance spectroscopy. The results exhibited that the AgVO3/BiVO4 samples were of good purity. After compounding AgVO3, the crystal structure of BiVO4 did not change, but the morphology changed from a stone cage to a single irregular stone, and had a enhanced light absorption performance. At the same time, the formation of a heterojunction structure further promoted the separation of photo electron-holes, then improving the photocatalytic activity. When the mass ratio of AgVO3/BiVO4 was 70%, the composite showed the highest photocatalytic activity, and the degradation rate of methyl orange was 96.7%, 86.5% higher than pure BiVO4. Recycling experiments presented that heterojunctions retained excellent photo-stability after five-time recycles. And the holes were the main active species in the process of photocatalytic degradation.