g-C_3N_4/石墨烯复合材料的制备及光催化活性的研究

以三聚氰胺和氧化石墨烯颗粒为原料,通过研磨负载、氮气气氛下煅烧的方法制备了石墨相氮化碳/石墨烯(g-C_3N_4/r GO)复合光催化剂.主要采用TEM、XRD、PL等对其进行表征,研究了其在模拟太阳光下对罗丹明B(Rh B)的光催化性能.PL分析结果显示,相比单一的g-C_3N_4,g-C_3N_4/r GO的光生电子-空穴对的复合几率大大降低.光催化结果表明,和单一g-C_3N_4相比,首次使用研磨负载、氮气保护气氛下煅烧制备的g-C_3N_4/r GO(2%)光催化反应180min后对Rh B的降解率提高了43.2%.这是因为石墨烯为g-C_3N_4提供了电子转移场所,实现光生电子-空穴的有效分离,从而提高了光催化效率.本文还考察了添加叔丁醇(TBA)和三乙醇胺(TEOA)后对g-C_3N_4/r GO光催化的影响,实验结果表明:光生空穴是g-C_3N_4/r GO光催化体系中的主要活性物质之一.

Preparation and photocatalytic activity of g-C3N4/rGO composite

Graphitic carbon nitride/reduced graphene oxide (g-C₃N₄/rGO) composite was synthesized by grinding and calcination process. Then it was characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), and photoluminescence spectra (PL). The photocatalytic activity of g-C₃N₄/rGO was evaluated by degrading rhodamine B (RhB) under simulated solar light irradiation. The results of PL analysis demonstrated that the recombination of photo-generated electrons and holes was inhibited compared with pure g-C₃N₄. The results of photocatalytic degradation of RhB showed that the removal efficiency of RhB with g-C₃N₄/rGO(2%) composite in 180min was improved by 43.2% compared with pure g-C₃N₄, which was attributed to the facilitated electrons transfer in g-C₃N₄/rGO composite. The main oxidative species was also detected by addition of TBA and TEOA in the photocatalytic process. The result suggested that holes were mainly responsible for the degradation of RhB in g-C₃N₄/rGO photocatalytic system.