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通过热聚合的方法使氮化碳(CN)与Ag/AgI/γ-Al_2O_3发生耦合作用,制备出CN-Ag/AgI/γ-Al_2O_3可见光催化剂.采用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)和紫外可见漫反射光谱(UV-vis DRS)等方法对合成的样品进行了表征,并通过可见光下甲基橙(MO)的降解实验探究了CN对Ag/AgI/γ-Al_2O_3光催化活性及稳定性的影响.结果表明,CN的掺杂改变了Ag纳米颗粒的形状与粒径,且Ag、AgI与CN之间形成强相互作用.与Ag/AgI/γ-Al_2O_3相比较,在可见光波长分别为λ>420、450和510 nm时,CN-Ag/AgI/γ-Al_2O_3对MO具有更高的催化降解效率,光反应30 min后,MO的去除率分别为97%、97%和93%.同时,CN的加入显著地增加了Ag/AgI/γ-Al_2O_3的稳定性,抑制了反应过程中Ag~+的释放量,而且反应前后CN-Ag/AgI/γ-Al_2O_3样品的结构没有明显的变化.其活性和稳定性提高的主要原因是CN加速了电子由MO传递至Ag纳米颗粒的过程,同时Ag颗粒等离子体共振(plasmon)效应的增强也有利于MO的催化降解.不同自由基捕获剂的影响实验表明,O_2~(·-)和h~+是反应体系的主要活性物种.
The CN-Ag / AgI / γ-Al 2 O 3 visible light photocatalysts were prepared by the thermal polymerization of carbon nitride (CN) and Ag / AgI / γ-Al 2 O 3 .The XRD, X-ray photoelectron energy (XPS), transmission electron microscopy (TEM) and UV-vis DRS were used to characterize the synthesized samples. The degradation of CN The results show that the doping of CN changes the shape and particle size of Ag nanoparticles, and the strong interaction between Ag, AgI and CN is formed.Compared with Ag / AgI / γ-Al 2 O 3 photocatalytic activity and stability, Compared with AgI / γ-Al 2 O 3, CN-Ag / AgI / γ-Al 2 O 3 had a higher catalytic efficiency for MO at visible light wavelengths of λ> 420, 450 and 510 nm, respectively. The removal rate of CN was 97%, 97% and 93% respectively. Meanwhile, the addition of CN significantly increased the stability of Ag / AgI / γ-Al 2 O 3 and inhibited the release of Ag ~ + during the reaction. The structure of Ag / AgI / γ-Al 2 O 3 samples showed no obvious change.The main reason for the increase of activity and stability was that CN accelerated the transfer of electrons from MO to Ag nanoparticles Catalytic, while enhancing Ag particle plasmon resonance (Plasmon) effect is also conducive to the degradation of MO different experiment showed a radical trapping agent, O_2 ~ (· -) and h ~ + is the primary active species of the reaction system.