碳掺杂pg-C3N4的制备及其光催化性能研究

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-C₃N₄)，通过碳掺杂和金纳米粒子(AuNPs)负载对pg-C₃N₄进行改性得到Au/pg-C@C₃N₄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-C₃N₄原有的片层结构，但明显提高了pg-C₃N₄的比表面积（高达158.2 m²/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=0.078 4 s^-1）。因此，通过碳掺杂和纳米Au负载改性pg-C₃N₄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。

Research of the preparation of carbon-doped pg-C3N4 and its photocatalytic performance

In order to improve the photocatalytic activity of a single semiconductor material, porous graphite phase carbon nitride (pg-C3N4) with high specific surface area was prepared by hydrothermal method. Then pg-C3N4 was modified by carbon doping and gold nanoparticles (AuNPs) loading to obtain Au/pg-C@C3N4 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-C3N4, but significantly improves the specific surface area of pure pg-C3N4 (up to 1582 m2/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 05% (mass fraction), the nanocomposite has the highest photocatalytic performance (apparent reaction rate constant k=0078 4 s-1). Therefore, the study on the preparation of composite photocatalyst with high activity by carbon doping and gold nanoparticle loading to modified pg-C3N4 provides a theoretical basis for further improving the catalytic activity of carbon nitride-based catalysts in the future.