杂化纳米金刚石/石墨相氮化碳异质结构建及其可见光分解水制氢性能研究

Graphite-phase carbon nitride (g-C3N4) has attracted extensive attention as a promising photocatalyst due to its characteristics of suitable band structure, high chemical stability, rich sources and simple preparation. However, the two core problems of low photon absorption efficiency and low separation efficiency of photo-generated carriers seriously restrict the practical application of g-C3N4. Coupled with other semiconductor material to form a heterostructure is a useful method for g-C3N4. In this project, we will use microstructure control means to enhance the defect concentration and conductivity of the photo-generated carrier for as-prepared hybrid nanodiamond (HND), thus, the photo absorption efficiency and carrier separation efficiency of ND photocatalysts could be enhanced, and the visible light photocatalytic properties of ND could also be improved. Then, we will prepare the HND/g-C3N4 heterostructure, and study the visible light photocatalytic activity of hydrogen evolution by water splitting. Finally, the mechanism of photocatalytic reaction and the effect of interfacial structure on its photocatalytic activity will be explored by combining experimental data and theoretical analysis. The development of this project provides a new idea to prepare efficient carbon based photocatalyst.

石墨相氮化碳（g-C3N4）因具有能带结构合适、化学稳定性高、来源丰富、制备简单等特性，使其作为一种极具潜力的光催化剂而引起了人们的广泛关注。然而，光子吸收效率低和光生载流子分离效率低的两个核心问题严重制约了g-C3N4实际应用。目前，g-C3N4通过与其他半导体材料结合构建异质结是解决这两个问题的有效方案。本项目拟采用微结构调控手段对纳米金刚石（ND）进行结构调控，使形成的杂化纳米金刚石（HND）同时具有缺陷浓度高和光生载流子传导能力强的特性，从而分别增强ND光催化剂光子吸收强度和载流子传导速率。然后，本项目拟制备HND/g-C3N4异质结，研究其可见光分解水制氢的催化活性。最后，结合实验数据和理论计算结果分析界面结构对其光催化活性的影响及其光解水制氢的催化机理。本项目的开展为实现制备高效碳基光催化剂材料的目标提供了新的思路。

能源危机和环境治理是目前社会发展面临的重要问题。借助于光催化技术不但可以把太阳能转化为清洁能源氢能，还可以把环境中有机污染物降解为环境友好的小分子。本项目针对碳基光催化剂氮化碳的光生载流子易复合及光子吸收效率低的问题，提出了构筑碳基异质结的方案。首先通过调控实验条件制备了杂化纳米金刚石，借助于其优越的载流子传导速率和光散射作用，赋予了所制备的杂化纳米金刚石/石墨相氮化碳光催化剂较高的载流子分离效率及光子利用率，最终优化了石墨相氮化碳的光催化活性。该项目中，我们对所制备材料进行了微观结构、表面形貌、元素组成、电化学性能、催化活性进行了分析，并结合实验结果分析了光催化制氢反应的催化机理。该项目的开展为推动高效碳基光催化剂的制备及能源转化方面提供了新思路。