可见光响应的Co3(PO4)2/Ag3PO4纳米复合光催化剂的制备及表征

采用简单的化学偏聚法合成出Ag₃PO₄纳米颗粒、磷酸钴（Co₃（PO₄）₂,CoP）纳米片以及它们两者的纳米复合结构（CoP/Ag₃PO₄）,同时还比较了它们的可见光催化活性. 采用场发射扫描电镜（FESEM）、X 射线衍射（XRD）、紫外-可见（UV-Vis）吸收光谱以及光致发光谱等手段对其形貌、结构、光学以及可见光催化性能等进行表征. 结果表明,CoP/Ag₃PO₄复合纳米结构的可见光降解甲基橙（MO）的速率和循环稳定性均明显优于其它两种物质. 这表明CoP应该起着共催化剂的作用,它能够抑制光生电子与空穴之间的复合,并且提供大量高活性的光生空穴. 此外,我们还发现CoP/Ag₃PO₄降解另一种阳离子型染料——罗丹明B（RhB）的能力则远不如纯Ag₃PO₄,这可能是与光催化剂的表面性质发生改变有关,造成更低的RhB吸附能力. 本文提供了一种廉价制备高效可见光催化剂的新方法.

Preparation and Characterization of Co3(PO4)2/Ag3PO4 Nanocomposites for Visible-Light Photocatalysis

In this study, Ag₃PO₄ nanoparticles (NPs), cobalt phosphate (Co₃(PO₄)₂, CoP) nanosheets (NSs), and their composites (CoP/Ag₃PO₄) were synthesized via a facile chemical precipitation method. Their visiblelight photocatalytic activities were compared and investigated. The structural, morphological, optical, and visiblelight photocatalytic properties of the prepared samples were characterized by X-ray diffraction (XRD), fieldemission scanning electron microscopy (FESEM), ultraviolet- visible (UV- Vis) diffuse absorbance and photoluminescence (PL) spectroscopies. We found that both the degradation rate and cyclical stability of the CoP/Ag₃PO₄ hybrids increased significantly under visible-light irradiation when methyl orange (MO) was used as the target with reference to single-phase Ag₃PO₄ NPs or CoP NSs. This suggests that CoP might play a cocatalyst role, which suppresses carrier recombination and provides a large number of photogenerated holes. Additionally, we also observed that the CoP/Ag₃PO₄ hybrids hardly degraded Rhodamine B (RhB), a cationic dye. This behavior might be attributed to the lower amount of dye molecule absorption because of a change in surface polarity. We thus present a new approach for the development of low-cost and visible-light responsive photocatalysts.