为克服光催化材料可见光利用效率低的缺陷, 通过三聚氰胺高温缩聚的方法合成了石墨型氮化碳(g-C3N4)材料。采用XRD, SEM, UV-Vis技术对氮化碳材料的微观结构和光学性能进行了表征, 并通过降解罗丹明B溶液研究了缩聚温度和不同光源对光催化效率的影响。结果表明, 合成的氮化碳层片状结构保存良好, 尽管材料表面在高温下断裂形成了不规则的块体颗粒;随着煅烧温度的升高, 催化剂在紫外光和可见光部分的吸收都显著增强, 这可能是由于材料表面的岩石状块体颗粒提高了材料的比表面积, 同时降低了光的反射又提高了对光的吸收。在罗丹明B的光降解测试中, 催化剂在可见光和太阳光照射下均表现出了良好的催化效果, 缩聚温度为580 ℃时效果最好, 分别为94.8%(60 min)和91.1%(90 min)。该方法制备的石墨型氮化碳催化剂对利用清洁能源进行环境净化应用具有极大的潜在价值。

Graphited carbon nitride materials (g-C3N4) with high visble-light response were synthesized by thermal condensation of melamine at varied temperature. The microstructure and optical property of as- achieved catalysts were investigated by XRD, SEM and UV-Vis techniques, respectively. Moreover, rhodamine B solution was applied to measure the catalytical performance under the irradiation of different sources of light. The results showed that the major structures of g-C3N4 were kept, though lots of blocks were scattered on the surface because of the damage of lamellar structure caused by the high temperature. As the thermal temperature was increased, the adsorptions of light were greatly enhanced in both UV and Vis region, which might be due to the decrease in reflection and the increase in refraction at the lumpy surface. In the degradation of rhodamine B solution, all the samples showed high photocatalytic activities under the irradiation of both visible-light and sunlight, and 94.8% (60min, under Vis-light) and 91.1% (90min, under sunlight) of RhB were degraded when the thermal temperature was 580℃. This research would greatly enlighten the studies of environmental purification using clean green energy.