以壳聚糖构建具有高效单线态氧活性的碳基材料及催化性能研究

Singlet oxygen shows great potentials in photodynamic therapy, pollutant degradation, and organic synthesis due to its unique electronic structure and strong oxidizing ability. The bottleneck during the single oxygen generation is mostly caused by the generation of other reactive oxygen species (such as hydroxyl radical and superoxide radical) which will reduce the reaction efficiency and selectivity. For this problem, the project applicant proposes a novel in-situ preparation of metal/nitrogen-doped carbon catalysts with abundant hierarchical structure and good conduction ability of electron. Starting from the regulation and control of singlet-triplet energy gap of the materials, the novel catalyst will be synthesized by using step-by-step carbonization route with metal-chitosan aerogel self-templating method. The project intends to achieve the selective regulation of band gap and the highly selective productivity of singlet oxygen by means of adjusting the binding of doping element in catalysts. Furthermore, the effect and mechanism of the materials microstructure on singlet oxygen productivity will be elucidated by using various developed characterization techniques and theoretical calculations. Then, the novel catalysts will be used in the photocatalytic selective sulfoxidation reaction. The mechanism of the reaction, and the catalytic activity, stability and recycling performance of the optimized catalysts will be studied. This project will provide theories and methods for the design of novel biomass based photocatalytic materials.

单线态氧具有独特的电子结构和强氧化能力，被广泛应用于光动力治疗、污染物降解、有机合成等领域。针对单线态氧产生过程中生成其他活性氧物种（如羟基自由基和超氧自由基）而降低反应效率和选择性的瓶颈问题，本项目提出从材料单线态-三线态能隙调控出发，采用金属/壳聚糖复合气凝胶自模板法，梯度碳化原位构建具有分级孔隙结构且电子传导率高的金属/氮共掺杂碳基催化材料。项目拟通过调变催化材料中掺杂元素的结合方式，实现对材料能隙的调控并赋予其对单线态氧的高选择性产生能力。借助多种现代表征技术与理论计算，阐明材料微观结构对单线态氧产生能力的影响规律与调控机制。在此基础上，将催化剂用于光催化硫醚选择性氧化反应，对其催化活性、稳定性及循环使用性能进行评价，揭示催化反应机理。项目预期成果为设计新型生物质基光催化材料提供相关的理论与方法。

活性氧物种被广泛应用于光催化反应及污染物降解等领域研究。设计合适的催化材料，对分子氧的活化起到至关重要的作用。.本项目中，通过离子交换过程将有机染料（Rose Bengal and Eosin Y）负载到壳聚糖衍生物中，设计了一种新型可回收的光催化材料。实验结果表明，该催化材料能高效选择性氧化硫醚合成亚砜。同时可该策略也适用于由烯烃和硫醇光催化合成亚砜。该催化体系具有可回收性、可重复使用性和简化的纯化过程等优点，使其具有良好的应用前景。同时，还开发了介孔石墨化氮化碳作为硫氰化转化的多相光催化剂。通过电子顺磁共振光谱(EPR)和荧光猝灭实验对反应机理进行了系统研究，并对参与光催化反应的活性氧进行了分析。.此外，还设计以纤维素为基材，经高温碳化、聚多巴胺涂层及水热矿化原位生长-FeOOH，制备复合光催化材料。PDA涂层的引入能够促进光生载流子在催化剂中的传输，并能有效地防止-FeOOH纳米颗粒团聚，从而显著提高催化活性。同时，还研究利用壳聚糖（N源）和木质素磺酸盐（S源）制备N, S共掺杂蜂窝煤形状碳基材料，用于活化过硫酸盐降解污染物。同时，将该催化材料拓展到电化学储能应用，具体良好的超级电容器性能。.在本项目资助下，取得一定研究的研究成果，在Dyes and Pigments，New Journal of Chemistry，Carbon等学术期刊发表SCI论文4篇，培养研究生2名，完成预期研究目标。