Ag_3PO_4/MoS_2纳米片复合催化剂制备及可见光催化性能

采用机械球磨法成功制备Ag_3PO_4/MoS_2纳米片复合催化剂。运用X射线衍射仪(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、紫外可见漫反射光谱(UV-Vis)和荧光发射光谱(PL)对复合催化剂的结构和形貌进行了表征。结果表明,Ag_3PO_4纳米粒子均匀地附着在MoS_2纳米片层结构上,两者形成紧密结合。以亚甲基蓝为模拟污染物,研究复合催化剂在可见光照射下的光催化特性;通过循环实验考察复合催化剂的稳定性。结果显示,含有1%的MoS_2纳米片与Ag_3PO_4形成的复合催化剂在30 min内对亚甲基蓝的降解率为95%,其降解动力学常数是纯相Ag_3PO_4的2倍。经过5次循环实验后复合催化剂对于亚甲基蓝的降解率为84%,而纯Ag_3PO_4对于亚甲基蓝的降解率仅为35%。Ag_3PO_4/MoS_2纳米片复合催化剂具有优良的光催化活性和高稳定性,主要归因于二硫化钼纳米片与磷酸银形成异质结,磷酸银激发的电子和二硫化钼纳米片产生的空穴直接复合,从而促使光生电子从磷酸银晶体表面快速分离,减轻了磷酸银的光电子腐蚀,同时也提高了复合物的光催化活性。

Synthesis and Visible Light Photocatalytic Performance of Ag3PO4/MoS2 Nanosheets Composite Photocatalyst

The Ag₃PO₄/MoS₂ nanosheets composite photocatalyst was successfully prepared via a mechanical milling method. The structure of composite photocatalyst was characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectroscopy (DRS) and photoluminescence spectroscopy (PL). The results indicate that Ag₃PO₄ nanoparticles are successfully coupled into the surface of MoS₂ nanosheets. The photocatalytic activity of composite photocatalyst was evaluated by the degradation of organic methylene blue (MB) under visible light irradiation. The obtained Ag₃PO₄/1%MoS₂ nanosheets composite photocatalyst exhibite the optimal photocatalytic performance, which can degrade almost all MB under visible-light irradiation within 30 min. The kinetic constant of MB degradation with Ag₃PO₄/1%MoS₂ nanosheets composite photocatalyst is about 2 times as high as that of the pure Ag₃PO₄. The enhanced photocatalytic activity is mainly attributed to the efficient separation and transport of photo-induced electron-hole pairs in the heterojunction structure. The recycling experiment shows that the photocatalytic activity of Ag₃PO₄/1%MoS₂ nanosheets composite photocatalyst is maintained at about 84% after 5 cycles, while the photocatalytic activity of the pure Ag₃PO₄ decreases to 35%. The high photocatalytic stability is due to the successful inhibition of the photo-corrosion of Ag₃PO₄ by transferring the photo-generated electrons of Ag₃PO₄ to MoS₂ nanosheets.