Ag_3PO_4/MoS_2纳米片复合催化剂制备及可见光催化性能

Synthesis and Visible Light Photocatalytic Performance of Ag_3PO_4/MoS_2 Nanosheets Composite Photocatalyst

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。

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 Ag3POJl %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/I%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 heterojunetion 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 MoS： nanosheets.