石墨相氮化碳的制备及其光催化性能的研究

Preparation and Photocatalytic Properties of Graphite Phase Carbon Nitride

通过煅烧双氰胺制备了一种具有优异可见光活性的石墨相氮化碳（g-C3N4）光催化剂。紫外-可见吸收光谱表明,该光催化剂的吸收边在460nm左右（Eg=2.7eV）。该光催化剂采用X射线衍射图谱、扫描电子显微镜和高分辨透射电子显微镜等进行表征分析。结果表明,该光催化剂为石墨相,呈片层状结构,颗粒粒径约为5~7nm。甲基橙溶液的降解实验结果表明,其在2.5h内降解率可达86.2%。另外,还对该光催化剂的催化机理进行了探究。结果表明,在催化降解过程中起主要作用的是h^＋和·O2^-。

A metal-free photocatalyst g-C3 N4 with layer structure was prepared by calcining dicyandiamide, showing high visible-light photocatalytic activity for the degradation of methyl orange in water. X-ray diffractometer （XRD）.scan- ning electron microscope （SEM） and high resolution transmission electron microscopy （HRTEM） were used to character- ize the structure of photocatalyst g-Ca N4. The results indicate that the photocatalyst is graphite-like carbon nitride and the size of the particles is about 5-7 nm. The spectrum of UV-vis absorption indicates that the absorption edge of the g-C3 N4 is 460 nm, corresponding to the band gap energy of 2. 7 eV. The degradation experiments of methyl orange in water show that its degradation efficiency can reach 86. 2% in 2. 5 11. The photocatalytie mechanism experiments indicate that h^＋ and ·O2^- play a major role in the degradation of methyl orange in water.