(1. 湖北工业大学 机械工程学院，武汉 430068；
2. 湖北工业大学 绿色轻工材料湖北省重点实验室，武汉 430068)
摘 要: 利用二氰二胺与尿素的复合粉末作为前驱体，通过简单的高温烧结法制备石墨相g-C3N4光催化剂。采用XRD、FESEM、TEM、BET、XPS和DRS等分析手段对g-C3N4的微观结构进行表征，并考察尿素加入量、催化剂浓度、染料初始浓度、溶液pH值以及光源等对光催化降解甲基橙的影响。结果表明：复合粉末前驱体所制备的g-C3N4具有典型的多孔结构，相比于纯二氰二胺或纯尿素所制备的产物具有更高的比表面积。随着尿素含量增加，g-C3N4产物的禁带宽度逐渐增大,而其表面的C和N摩尔比则从0.70降至0.60。可见光光催化降解甲基橙的实验结果显示随着尿素含量的增加，g-C3N4的光催化活性也随之增强，表明g-C3N4的表面化学组成及其氧化还原能力对可见光光催化活性起主要作用，而比表面积起次要作用。
关键字: g-C3N4；甲基橙；尿素；二氰二胺；光催化
（1. School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China;
2. Hubei Provincial Key Laboratory of Green Materials for Light Industry,
Hubei University of Technology, Wuhan 430068, China）
Abstract:g-C3N4 photocatalysts were prepared by high temperature calcination method using the mixture powders of melamine and urea as precursors. XRD, FESEM, TEM, XPS, BET and DRS were employed to characterize the microstructure of as-synthesized g-C3N4 photocatalysts. The influences of urea content (mass fraction) in mixture powders, photocatalysts concentration, initial dye concentration, pH value of solution, as well as the light sources on the methyl orange degradation efficiency, were evaluated. The results show that g-C3N4 photocatalysts synthesized by mixture powders present the typical porous structure, which exhibit the higher surface area than that prepared by pure melamine or pure urea. The band gap of g-C3N4 photocatalysts increases with the increase of urea content in mixture powders. However, the surface mole ratio of C and N decreases from 0.70 to 0.60. Methyl orange photodegradation results under visible light irradiation demonstrate the surface chemical composition and the redox ability of g-C3N4 plays a major role, while the surface area of photocatalysts plays a minor role.
Key words: g-C3N4; methyl orange; urea; melamine; photocatalysis
