石墨相氮化碳/蓝磷异质结的光催化性能研究

Research on Photocatalytic Properties of g-C_(3)N_(4)/xBlueP Heterojunction

二维材料因其独特的性质在众多研究领域备受关注,而异质结是减小带隙、促进空间电荷有效分离的重要手段,因此构建二维异质结构是提高材料光催化性能的一种关键途径。基于第一性原理方法,可以有效地设计出合适的异质结构。该文通过第一性原理计算系统地研究了几种不同的石墨相氮化碳/蓝磷(g-C_(3)N_(4)/xBlueP,x=1,2,3)异质结的电子和光学性质。计算结果表明,g-C_(3)N_(4)/2BlueP异质结具有最合适的带边位置、较宽的光学响应范围和良好的光吸收能力。通过进一步施加适当的双轴应力,发现可实现g-C_(3)N_(4)/2BlueP异质结类型的转变,解决了I型异质结的高电子−空穴复合问题,这对于实现高效光生电荷分离有着重要的意义。合适的应力调控后的g-C_(3)N_(4)/2BlueP异质结具有明显优于两种组分材料的光吸收性能,在可见光区的光吸收强度明显增大。

Two-dimensional materials have attracted much attention due to their unique properties,and heterojunction is an important means to reduce the band gap and promote effective charge separation.Therefore,the construction of two-dimensional heterostructure is a key way to improve the photocatalytic properties of materials.First-principles calculations can be used to effectively design suitable heterostructure.The electronic and optical properties of g-C_(3)N_(4)/xBlueP(x=1,2,3)heterojunction with different structures have been studied by first-principles calculations.The results show that the g-C_(3)N_(4)/2BlueP heterojunction has the most suitable band edge positions,wide optical response range and good light absorption capacity.The type transformation of g-C_(3)N_(4)/2BlueP heterojunction can be realized by applying appropriate biaxial strain,which solves the problem of high electron-hole recombination of type I heterojunction.This is particularly valuable for achieving efficient photogenerated charge separation.The strain-regulated g-C_(3)N_(4)/2BlueP heterojunction is found to significantly increase the absorbance of the visible light,compared with the light absorption properties of the two constituent materials.