Ag-AgI/CN/MA复合物的制备及其可见光催化性能

Preparation of Ag-AgI/CN/MA Composites and Their Visible-light Photocatalytic Performance

采用沉淀法和热聚合法分别将AgI、氮化碳(CN)负载在介孔γ-Al_2O_3(MA)上,并通过光还原银离子成功制备了等离子体诱导可见光催化剂Ag-AgI/CN/MA.利用X射线衍射(XRD)、X射线光电子能谱(XPS)、场发射扫描电子显微镜(FESEM)、紫外可见漫反射光谱(UV-vis DRS)和透射电子显微镜(TEM)对Ag-AgI/CN/MA复合材料进行表征,并对其在可见光照射下(λ>420 nm)的光催化性能进行了研究,考察了初始溶液pH值及催化剂投加量等条件对光催化反应的影响.结果表明,表面银以Ag+和Ag0形式共存,并且Ag和AgI均匀地分散在CN的表面.与CN和Ag-AgI/MA相比,Ag-AgI/CN/MA复合物对甲基橙(MO)具有更高的可见光催化降解效率,且反应过程中Ag+的释放量显著减少,显示出良好的稳定性.当溶液pH值为7、催化剂投加量为1 g·L^(-1)时,Ag-AgI/CN/MA-2显示出最优的催化性能.同时,其对罗丹明B(Rh B)、甲基红(MR)和刚果红(CR)等不同电性的染料均体现出良好的催化性能.

Ag-AgI/CN/MA photocatalysts were prepared by coupling graphitic carbon nitride（ CN） with AgI/γ-Al2O3（ AgI/MA）through a thermal polymerization method and Ag nanoparticles were deposited by photoreduction. The catalysts were characterized by Xray diffraction（ XRD）,X-ray photoelectron spectroscopy（ XPS）,field emission scanning electron microscopy（ FESEM）,UV-vis diffuse reflectance spectra（ UV-vis DRS）,and transmission electron microscopy（ TEM）. The photocatalytic performance of different catalysts was evaluated under visible light irradiation（ λ 420 nm）. The effects of different conditions such as pH and catalyst dosage on photoreactions were also investigated. The results showed that Ag＋and Ag0 coexisted on the surface of the catalyst and Ag and AgI nanoparticles were uniformly distributed on the surface of CN. Compared with CN and Ag-AgI/MA,Ag-AgI/CN/MA composites exhibited better visible-light photocatalytic activity and stability,and the release of silver ions was significantly suppressed. At the catalyst dosage of 1 g·L^-1and pH = 7,Ag-AgI/CN/MA-2 exhibited the optimal photocatalytic performance. Ag-AgI/CN/MA-2 also showed high photoactivity for the degradation of dyes with different charges,such as rhodamine B（ Rh B）,methyl red（ MR） and congo red（ CR）.