环糊精调控量子点与分子催化剂自组装光催化产氢研究

Direct conversion of solar energy into chemical fuels such as hydrogen by photoinduced water splitting is one of the promising methods to meet globally ever-increasing energy demands and solve pollution problems. The key issue for approaching this target is to develop highly efficient, robust, and cheap photocatalytic systems. It has been found that the integration of molecular catalysts with inorganic light harvesting materials is an effective method to construct highly efficient and robust photocatalytic systems. This project focus on the homogeneous β-CD-controlled self-assembling systems based on CdTe quantum dots and molecular catalysts for photocatalytic hydrogen production in water. (1) The hydrophobic cavity of CD could mimic the protein environment that surrounds the active site of metalloenzymes to prompt the stability of molecular catalyst. (2) The concentration of catalyst on the surface of photosensitizer could be increased by the self-assembled reaction between catalyst, CD and QDs, while the photoinduced electron would be accelerated by shorten the distance between QDs and catalyst. (3) The hydrophilic surface and macrocyclic structure of CD impede the aggregation of QDs in solution. According to the project, we hope to find out a simple and effective way to improve efficiency service life of the photocatalytic system for hydrogen production.

利用太阳能光解水制氢是解决人类社会面临的能源危机和污染问题的理想途径。研究表明，分子催化剂与无机光敏材料结合是构建高效、稳定、经济适用的均相光催化产氢体系的行之有效的方法。本项目拟将含巯基的β-环糊精通过S原子连接在量子点CdTe表面，并通过其空腔包结分子催化剂，构建纯水相自组装光催化水分解制氢体系：①利用环糊精的疏水空腔模拟自然界生物酶中的第二配位环境，提高分子催化剂的稳定性；②通过量子点、环糊精、催化剂三者之间的自组装反应，提高光敏剂表面催化剂的浓度，缩短光敏剂和催化剂之间的距离，加快光诱导电子转移速率，提高光催化效率；③利用环糊精的亲水大环外壳提高量子点和催化剂在水中的溶解度，抑制量子点的凝聚，提高光敏剂的稳定性。本项目的顺利开展，将为设计出更高效、更稳定的光催化水分解制氢体系提供实验基础和理论依据。

人工光合作用是指利用阳光将水、二氧化碳转化成氧气和高附加值的燃料分子（H2、CO、CH4等）。本项目提出针对不同的催化体系，引入合适的分子间作用力，通过超分子作用来提高体系的催化性能。主要研究内容分为以下三个方面：1）以大环化合物为主体，产氢催化剂为客体，通过主客体化学形成的包合物，再将其与光敏剂链接，成功构建了[光敏剂-大环化合物-催化剂]三元超分子体系。2）将超分子作用应用于水氧化反应中。通过静电作用促进两个催化剂分子之间的O-O键耦合，使Ru(bda)类水氧化催化剂的活性提高了一个数量级。3）我们还设计合成了一些具有电催化产氢性能的功能配合物与纳米材料，探索其构效关系。