多孔纳米片状石墨相氮化碳的制备及其可见光催化

摘要

Porous carbon nitride nanosheet was prepared by the simple oxygen etching using melamine and thiourea as precursors respectively.The porous g-C3N4 (TCNS) nanosheet prepared by thiourea is thinner than the porous carbon nitride (MCNS) nanosheet prepared by melamine,and the monolayer thickness is about 30 nm.Meanwhile,TCNS demonstrates an obvious layered structure and a band gap of 3.03 eV,which is higher than that of graphitic carbon nitride (2.77 eV).An enlarged band gap can give carrier stronger ability of oxidation reduction for photocatalysis.The larger specific surface area (114 m2·g-1) can provide more active sites,and the nanosheet structure can effectively promote the separation and transfer of electrons and holes,which makes TCNS have higher photocatalytic activity.%以三聚氰胺和硫脲为前驱体,通过简易的氧气刻蚀制备了多孔纳米片状氮化碳.相比于三聚氰胺制备的薄片状氮化碳(MCNS),以硫脲制备的多孔纳米片状的g-C3N4(TCNS)片层更薄,其单片厚度约为30 nm,且TCNS的层状结构明显,能带隙约为3.03 eV,高于石墨相氮化碳(2.77 eV),更宽的禁带赋予载流子更强的氧化还原能力.较大的比表面积(114 m2·g-1)可以提供更多的活性位点.同时纳米片状结构可以促进电子与空穴的有效分离和转移,且能有效地降低光生载流子的复合率,因而TCNS具有更高的光催化活性.