g-C3N4/RGO的制备、光催化降解性能及其降解机理

尿素固相反应得到石墨相氮化碳(g-C₃N₄),石墨(G)被氧化制得氧化石墨(GO),GO被还原制得石墨烯(RGO),通过3种复合方法分别制得g-C₃N₄/RGO材料.通过对污染物亚甲基蓝、罗丹明B和甲基橙的降解,考察了g-C₃N₄与GO不同复合比9.7:1、9.3:1、9:1、8:1和6.7:1对光催化剂g-C₃N₄/RGO光催化性能的影响.同时考察了复合物对污染物的选择性降解.用X-射线衍射谱(XRD)和傅里叶变换红外光谱(FT-IR)对催化剂的结构性质进行了表征.结果表明,g-C₃N₄与GO混合-水合肼还原-高温固相反应法制备的g-C₃N₄/RGO,时间最短,产量较高,对罗丹明B的降解效果最佳,说明该方法较好.另外,当g-C₃N₄与GO的质量比为9.7:1时,制备的g-C₃N₄/RGO降解效果最佳.还有,该复合材料对亚甲基蓝的降解效果最佳,罗丹明B次之,甲基橙最差.机理研究结果表明超氧自由基在光催化过程中起主导作用,羟基自由基起次要作用.

Preparation,photocatalytic degradation performance and degradation mechanism of g-C3N4/RGO

Graphite phase carbon nitride(g-C₃N₄)was obtained by urea solid phase reaction,graphite(G)was oxidized to prepare graphite oxide(GO),GO was reduced to obtain graphene(RGO),and g-C₃N₄/RGO was prepared by three composite methods.Through the degradation of methylene blue,rhodamine B and methyl orange,the effects of different composite ratios of g-C₃N₄and GO,9.7:1,9.3:1,9:1,8:1 and 6.7:1,on the performance of photocatalyst g-C₃N₄/RGO were investigated.At the same time,the selective degradation of pollutants by the composite was investigated.The structure and properties of the catalyst was characterized by X-ray diffraction(XRD)and Fourier transform infrared(FT-IR).The results showed that the g-C₃N₄/RGO prepared by the method of mixing g-C₃N₄and GO-hydrazine hydrate reduction-high temperature solid-phase reaction had the shortest time,higher yield and the best degradation effect on rhodamine B,indicating that the method was better.In addition,when the mass ratio of g-C₃N₄to GO was 9.7:1,the prepared g-C₃N₄/RGO had the best degradation effect.In addition,the composite material had the best degradation effect on methylene blue,followed by rhodamine B and methyl orange.The results of mechanism studies showed that superoxide radicals played a dominant role in the photocatalytic process,while hydroxyl radicals played a secondary role.