BiPO_4@Ag_3PO_4核/壳异质结的制备及光催化性能

Fabrication and Photocatalytic Activity of BiPO_4@Ag_3PO_4 Core/Shell Heterojunction

采用简单的水热法结合离子交换法制备了BiPO4@Ag3PO4核/壳异质结光催化剂,采用场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)、紫外-可见漫反射光谱仪(DRS)和X射线光电子能谱仪(XPS)等对催化剂的形貌、组成、晶型和光物理性质等进行了研究,用罗丹明B(RhB)为模拟水体中有机污染物分别在可见光和模拟太阳光照条件下对催化剂的催化活性进行了测试.结果表明,负载Ag3PO4的BiPO4微米棒具有较高的可见光响应,其核/壳异质结结构有利于光生电子-空穴对的有效分离和提高对RhB的光催化降解效率,在可见光和模拟太阳光照射条件下分别在60和40 min可使RhB完全脱色降解.活性物种检测实验结果证明,该催化剂在污染物降解过程中主要的机理是光生空穴的直接氧化.

BiPO4@Ag3PO4 core/shell heterojuction photocatalyst was synthesized through a facile hydrothermal process followed by the ion-exchange method. The morphology, crystallinity, composition, and photophy- properties of the catalyst were systematically investigated by scanning electron microscope （SEM）, X-ray diffraction（ XRD）, energy dispersive X-ray analysis, UV-Vis diffuse reflectance spectrophotometer（DRS） and X-ray photoelectron spectroscopy（XPS）. Meanwhile, Rhodamine B （RhB） was chosen as the target pollutant to evaluate the photocatalytic activity of BiPO4@Ag3PO4 photocatalyst under the visible light and simulated sunlight irradiation, respectively. The results show that RhB was almost totally degraded in 60 min under visible-light irradiation and in 40 min under sunlight irradiation, respectively. The BiPO4@Ag3PO4 core/shell heterojunction photocatalyst displayed enhanced photocatalytic activity against RhB, which is attributed to the effective charge separation by the core/shell heterojuction between the Ag3PO4 and BiPO4. Active species detection experiments proved that during the process of degradation of pollutants over the core/shell microrods, the main mechanism was the direct oxidation process by the photo-induced holes. Ag3PO4 shell can improve the absorption of the visible light effectively and also enhance the stability, dispersibility and photocatalytic activity of the photocatalyst. The BiPO4@ AgPO4 photocatalysts show attractive potential applications in pollution control, water splitting and solar cell.