碳掺杂pg-C_(3)N_(4)的制备及其光催化性能研究

Research of the preparation of carbon-doped pg-C_(3)N_(4) and its photocatalytic performance

为了提高单一半导体材料的光催化活性,采用水热法制备高比表面积的多孔石墨相氮化碳(pg-C_(3)N_(4)),通过碳掺杂和金纳米粒子(AuNPs)负载对pg-C_(3)N_(4)进行改性得到Au/pg-C@C_(3)N_(4)复合纳米材料,并对复合材料的组成、微观结构和性能进行表征。结果显示,碳元素的引入并未破坏pg-C_(3)N_(4)原有的片层结构,但明显提高了pg-C_(3)N_(4)的比表面积(高达158.2 m^(2)/g);AuNPs引入基体后,AuNPs的等离子共振效应可显著提高基体对可见光的吸收和光生电子-空穴的分离效率;当AuNPs含量为0.5%(质量分数)时,复合纳米材料具有最佳的光催化性能(表观反应速率常数k=0.0784 s^(-1))。因此,通过碳掺杂和纳米Au负载改性pg-C_(3)N_(4)可制备高活性复合光催化剂,为今后进一步提高氮化碳基催化剂的催化活性提供了理论基础。

In order to improve the photocatalytic activity of a single semiconductor material,porous graphite phase carbon nitride(pg-C_(3)N_(4))with high specific surface area was prepared by hydrothermal method.Then pg-C_(3)N_(4)was modified by carbon doping and gold nanoparticles(AuNPs)loading to obtain Au/pg-C@C_(3)N_(4)composite nanomaterials.The composition,microstructure and properties of the composites were characterized.The results show that the introduction of carbon element does not destroy the original lamellar structure of the pg-C_(3)N_(4),but significantly improves the specific surface area of pure pg-C_(3)N_(4)(up to 158.2 m^(2)/g).By introducing AuNPs into the matrix,the plasmon resonance effect of nanometals can be used to improve the absorption of visible light and the separation efficiency of photo generated electron-holes.It shows that when the AuNPs concentration is 0.5%(mass fraction),the nanocomposite has the highest photocatalytic performance(apparent reaction rate constant k=0.0784 s^(-1)).Therefore,the study on the preparation of composite photocatalyst with high activity by carbon doping and gold nanoparticle loading to modified pg-C_(3)N_(4)provides a theoretical basis for further improving the catalytic activity of carbon nitride-based catalysts in the future.