碳修饰的铋系纳米复合光催化剂的设计、制备与应用研究

Photocatalytic technique has been regarded as one of most important ways for solving problems related to environment and energy sources. Photocatalysts are the key of the photocatalytic techniques, while most of the reported photocatalysts have shortcomings, such as low absorption efficiency of visible-light, serious combination of photogenerated charge carriers, low photocatalytic activity, etc. This project aims to develop high-efficiency photocatalysts for overall water photosplitting and CO2 photoreduction by combing the advantages of bismuth-containing nano photocatalysts and graphitized carbon materials. The present research will be divided into three aspects: 1) Design and preparation of bismuth-containing nanocomposite photocatalytic materials, followed by modification of graphitized carbon. 2) Characterization of as-prepared bismuth-containing composite materials by various analysis techniques, especially the separation, transfer and recombination of photo-excited electrons and holes. 3) Examination of the photocatalytic performace of the as-synthesized materials in water photosplitting and CO2 photoreduction, and clarification of their catalytically active sites and photocatalytic mechanism. This project will yield several high-efficiency visible-light- driven photocatalysts, which will benefit the development of water photosplitting and CO2 photoreduction techniques. In addition, the present results will disclose the relationship between the catalytic performance and the structure of the catalysts and clarify the plausible reaction mechanism in the photocatalytic overall water splitting and CO2 reduction process, which will provide important information for the design of other novel photocatalysts.

光催化技术最有望成为解决能源、环境等难题的技术手段之一，其核心是光催化剂。针对目前所披露的光催化剂对可见光吸收较弱、光生载流子容易复合等不足，结合纳米铋系光催化剂具有强的可见光吸收能力以及石墨化碳材料具有良好的电子接受和运输能力等优点，本项目以研制在可见光下能够实现光解水制氢、二氧化碳光还原制备有机物的高效光催化剂为研究目标。主要研究内容为：1）拟构建复合型纳米铋系材料，然后通过石墨化碳材料进行修饰，从而制备高效的光催化剂；2）系统分析催化剂的组成、结构和性质，重点检测其光生载流子的分离、传输和复合情况；3）考察所制材料对光解水、二氧化碳光还原的催化性能，解析催化剂的结构、性质与性能之间的关系，并探究其在所选反应中的催化机理。本项目的成功实施，不仅可望获得高效光催化剂，揭示其催化机制，为开发新型光催化剂提供重要参考；还有望推动光解水制氢和二氧化碳利用，为缓解能源和环境危机做出重要贡献。

针对目前光催化剂对可见光的吸收弱、光生载流子容易复合等不足，结合铋系光催化剂具有强的可见光吸收能力以及石墨化碳材料具有良好的电子接受和运输能力等优点，本项目以获得在可见光下能够实现光催化分解水产氢和产氧、小分子烃类选择性氧化制备高附加值有机化学品的高效光催化剂为目标。（1）通过石墨相碳材料（g-C3N4）修饰铋系光催化材料，提高半导体光催化剂光生电子的转移速率，抑制半导体光催化剂光腐蚀等，从而制备高活性和高稳定性的可见光催化剂；（2）提出了可控制备碳材料修饰半导体制备特定形貌（空心多孔、多孔多壳层、多枝状）复合光催化剂的机制；（3）关联催化剂的结构与其性能之间的定性、定量关系，揭示铋系光催化剂在光催化分解水过程和光催化烃分子选择性氧化过程中的催化机理。为合成其他高效可见光催化剂提供重要参考信息。