通过液相沉积法制备了CeO2/g-C3N4复合光催化剂,利用X射线衍射、氮气吸脱附、紫外可见漫反射等方法对其进行了表征,考察了CeO2/g-C3N4复合光催化剂在可见光下降解罗丹明B的光催化活性,并对光催化反应机理进行了初步探讨.结果表明,复合光催化剂中g-C3N4和CeO2分别为石墨相和萤石相,其中存在堆积介孔结构,随着CeO2掺杂量的增加,CeO2/g-C3N4复合光催化剂的比表面积逐渐增大.CeO2掺杂提高了光生电子-空穴对的分离效率,使得CeO2/g-C3N4复合光催化剂的活性比单纯g-C3N4有所提升,其中CeO2掺杂量为6％的复合光催化剂活性最高,在可见光照射150 min后对罗丹明B染料的降解率可达94％.在复合光催化剂对罗丹明B的降解过程中,光生空穴是主要的活性物种.
A metal-free g-C3N4 photocatalyst was prepared by calcination method,and the CeO2/g-C3N4 composite photocatalysts were synthesized by deposition of CeO2.The samples were characterized by X-ray diffraction (XRD),nitrogen adsorption and UV-Vis diffuse reflectance spectroscopy (DRS) techniques.The photocatalytic activity and mechanism of the CeO2 doped on g-C3N4 catalysts were tested in the degradation of Rhodamine B (Rh B) under visible light irradiation.The results showed that the g-C3N4 was graphite phase and the CeO2 was fluorite phase in the composite photocatalysts,and the composites had mesoporous structure.The doping of CeO2 increased the surface area of the CeO2/g-C3N4 composite and improved the electron/hole separation efficiency.Compared with the pure g-C3N4,CeO2/g-C3N4 showed higher photocatalytic activity,and the photodegradation rate of Rh B was 94％ on the 6％ CeO2/g-C3N4 composite with visible light irradiation for 150 min.The photogenerated holes on the composite are the main active species in the photocatalytic degradation of Rh B.
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