纳米片层状类石墨氮化碳的制备及其光催化性能

Preparation and Photocatalytic Properties under Visible Light Irradiation of Graphite-like Carbon Nitride Nanosheets

以三聚氰胺为原料,采用热缩聚合成法,结合酸、热刻蚀协同改性工艺,制备了二维纳米片层状类石墨氮化碳(g-C3N4)。通过X射线衍射、扫描电镜、透射电镜、红外光谱、X射线光电子能谱、Raman光谱对试样进行了物相组成、显微形貌与分子结构表征。采用BET法分析了试样的比表面积,采用紫外–可见漫反射光谱、Mott–Schottky曲线分析了试样的可见光吸收性能与能带结构。通过可见光降解罗丹明B染料与盐酸四环素溶液,评估了试样的可见光催化性能。结果表明:采用热刻蚀改性剥离时,当三聚氰胺与NH4Cl的摩尔比为5:4时,所制备的纳米片层状g-C3N4厚度为47 nm,比表面积为22 m^2/g,可见光催化降解性能提高显著,相比未经过改性处理的g-C3N4,其降解效率提高了3.4倍;4 h内对盐酸四环素溶液的降解率达到83.2%。

Graphitic carbon nitride(g-C3 N4)nanosheet was synthesized by a facile fabrication method.Melamine was treated by a thermal polycondensation process.Pure g-C3 N4 was treated by acid etching,heat etching and coupling with NH4 Cl.The crystalline structure,morphology,specific surface area,band structure and visible absorption of the material were evaluated by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectroscopy analysis,X-ray photoelectron spectroscopy,Raman spectroscopy,specific surface area(BET analysis),ultraviolet visible diffuse reflection spectroscopy and Mott-Schottky curve analysis,respectively.The photocatalytic activity was estimated by the degradation of Rhodamine and tetracycline hydrochloride solution under visible light irradiation.The results show that a clear,ordered,2 D nanosheet g-C3 N4 structure with a layer thickness of 47 nm is formed,and the maximum specific surface area is a maximum(22 m^2/g)when the mole ratio of melamine to NH4 Cl is 5:4.The photocatalytic performance of bulk g-C3 N4 is enhanced after treatment.The photocatalytic degradation rate of the sample treated with melamine and NH4 Cl at a ratio of 5:4 is 3.4 times greater than that of untreated g-C3 N4.The sample degrades 83.2%tetracycline hydrochloride solution for 4 h.