类石墨相氮化碳二维纳米片的制备及可见光催化性能研究

Preparation and Visible-light Photocatalytic Activity of Graphite-like Carbon Nitride Two-dimensional Nanosheets

以三聚氰胺为原料制备类石墨相氮化碳(g-C_3N_4),采用球磨与超声联用技术制备g-C_3N_4二维纳米片。利用X射线衍射光谱(XRD)、紫外-可见漫反射(UV-Vis)光谱、扫描电镜(SEM)、透射电镜(TEM)、原子力显微镜(AFM)、荧光(PL)光谱等分析手段对制备的催化剂进行了表征。结果表明:g-C_3N_4二维纳米片具有与体相g-C_3N_4相同的晶体结构,片层结构仅有5个原子层厚。g-C_3N_4二维纳米片增加了对可见光的吸收,提高了光生电子-空穴对的分离效率。以染料罗丹明B的降解反应研究了g-C_3N_4二维纳米片在可见光下的催化性能。结果表明,球磨超声1h后制备的g-C_3N_4二维纳米片表现出最佳的光催化性能,150min内对罗丹明B的降解率高达94%,是体相g-C_3N_4的2倍。

The graphite-like carbon nitride （g-C3N4） two-dimension （2D） nanosheet were successfully prepared by a ball-mi-lling and ultrasound process using melamine as raw material. The samples were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, ultraviolet-visible diffuse reflectance spectroscopy （UV-Vis DRS）, atomic force microscope （AFM） and photoluminescence spectrum （PL）. The XRD results showed that g-C3N4 2D nanosheet had the same crystal phase as g-C3N4. The exfoliated products were comprised of only 5 C-N layers. The g-C3N4 2D nanosheet improved the absorption of visible light and accelerated the separation of photo-generated electron-hole pairs. The photocatalytic performance of the samples was evaluated by photocatalytic oxidation of rhodamine B （RhB） under visible light irradiation. The results show that g-C3N4 2D nanosheet exhibited a much higher degradation rate which is 2 times as high as that of pure g-C3N4.