多级孔结构石墨型氮化碳的构筑与高效可见光催化裂解水制氢研究

In recent years, people pay attention to the research of graphitic carbon nitride (g-C3N4) in photocatalytic water splitting based on the semiconductor properties, high stability, non-toxic, easy preparation, and so on. However, the fabrication of g-C3N4 photocatalyst with high visible light capture, high-performance hydrogen generation is the urgent problem to be solved. In this project, the visible light harvest efficiency of photocatalyst can be enhanced by employing the multiple scattering effect, reflection effect and slow photons effect of inverse opal structure photonic crystals, and the catalytic activity can be improved by the diffusion and mass transfer caused by mesoporous structure. With the combination of them, hierarchical porous structure coupled g-C3N4 photocatalyst can show high-performance hydrogen generation from water splitting in visible light. This project will adopt double template method for preparing such g-C3N4 materials. The effect of compound mode, pore size, structure, and morphology in hierarchical porous structure are investigation by varying preparation method, experimental parameters. Then, the controllable factors are obtained. On this basis, we research the photocatalytic water splitting of g-C3N4 with hierarchical porous structure, and clarify the effects of structure on the hydrogen production activity. Fourthermore, surface photovoltage/photocurrent technology were used for the research of photo-induced charge transfer properties of different samples to reveal the relationship between structure and performance. The project will not only provide scientific basis for the preparation of photocatalytic materials with high activity, but also be a new way in developing g-C3N4 with high efficient hydrogen production under visible-light, having the important academic significance.

依据石墨型氮化碳(g-C3N4)特殊的半导体特性，以及高稳定、无毒、易制备等特点，近年来在光催化裂解水制氢领域的研究备受关注，如何制备出高可见光捕获率、高催化制氢活性g-C3N4材料是目前亟待解决的问题。本项目利用反蛋白石结构光子晶体在调节和限制光子运动方面的优异性能，介孔结构在提高扩散、传质方面的优势，将两者结合形成的多级孔结构耦合到g-C3N4材料上实现可见光下高效催化裂解水制氢。拟通过双模板法制备多级孔结构g-C3N4，研究制备方案对多级孔的组合方式，实验条件对孔尺寸、结构、形貌的影响，实现可控制备。进而研究其光催化裂解水制氢过程，明确结构对制氢活性的影响。并利用表面光电压/光电流技术研究样品的表面与界面光生电荷行为，揭示材料结构与性能之间的内在规律，为制备高活性可见光催化制氢材料提供科学依据。这对开拓g-C3N4材料的高效催化制氢性能提供了一条崭新的途径，具有重要的学术意义。

高可见光捕获率、高效催化活性的石墨型氮化碳的构筑与性能方面的研究得到了国内外学者的重视。我们针对多孔结构石墨型氮化碳的制备及其结构与性能方面的问题进行了深入研究。首先我们通过模板法、非模板法和化学氧化法制备了多种微米级、纳米级孔状石墨型氮化碳。通过调整模板尺寸、反应温度等可以控制孔结构。进而通过界面聚合等方法制备孔状石墨型氮化碳复合材料，通过自组装方式制备三维石墨型氮化碳；将所得一系列孔状结构石墨型氮化碳应用于可见光催化研究，结果表明所制备的多孔结构及其复合材料不仅有利于捕获更多的可见光，而且有利于光生电子空穴的分离。这为高效催化材料的制备提供依据。