量子点/分子催化剂耦合人工光合成制氢体系的性能和机制研究

Inspired by photosynthesis in nature, the development of artificial photosynthetic systems to convert solar energy into chemical fuels in the form of hydrogen (H2), represents an important solution to the looming energy crisis and environmental pollution. The project is to create new artificial photosynthetic systems for hydrogen evolution based on quantum dots, which processes the advantages of both molecules and semiconductors. We intend to design and construct a series of hybrids of quantum dots and molecular catalysts (such as hydrogenase mimics or other molecular catalysts), with particular attention to the interaction between quantum dots and molecular catalysts on the efficiency and stability of photocatalytic hydrogen evolution. The objective is 1) to unravel the structure, morphology and distribution of the real catalytic center in the hybrid systems, 2) to illustrate the dynamic processes for light harvesting, charge transfer and separation and catalytic reaction in the hybrid systems, 3) to associate the catalytic activity and stability of the hybrid systems with the characteristics of quantum dots (dimension, composition, morphology, structure, surface properties etc.), the structure and function of molecular catalysts, and the interactions between quantum dots and molecular catalysts, and 4) to provide strong and convincing theoretical basis for the construction of practical artificial photosynthetic systems, which should not only be simple and effective, but also come from various sources with low cost.

借鉴自然界光合作用的机制和过程，通过人工光合成将太阳能转化为化学能，特别是氢能，是缓解当前能源短缺和环境污染的重要途径。本项目拟利用集分子与半导体特性于一身的量子点构筑人工光合成制氢体系，重点研究量子点与铁氢化酶人工模拟分子或分子催化剂耦合体系中量子点、分子催化剂之间的相互作用对光催化制氢性能的影响，揭示催化过程中实际催化中心的结构、形态及分布，阐明光子吸收、电子转移和电荷分离及催化反应的动态学，探究量子点特性（如：尺寸、组成、形貌、结构、表面态等）、分子催化剂结构与功能、及二者之间的作用方式对催化效率和体系稳定性的影响，为构筑来源广泛、廉价高效、简单易得的实用人工光合成体系奠定坚实的理论基础。

发展量子点/分子催化剂的构筑策略，明晰相关物理化学过程和机制有助于发展新型光催化体系。本项目以设计合成量子点与催化剂分子耦合的光催化体系为主线，合成了基于不同组成、结构、及表面态的量子点与分子催化剂为功能核心单元的光催化剂，通过研究量子点、分子催化剂二者之间相互作用对催化中心负载及催化效率的影响，得到了几个催化效率较高的光催化制氢体系。进一步，基于时间分辨X射线吸收精细结构（XAFS）光谱技术，并以探究催化过程中实际催化中心的结构、功能、催化机制为切入点，我们重点研究了光催化过程中光诱导电子转移和电荷分离过程，分析了催化中间体结构、电子态分布、载流子迁移速率对光催化机制作用机理，为构筑来源广泛、廉价高效、简单易得的实用人工光合成催化制氢体系奠定了一定的理论基础，相关研究结果共发表SCI论文10篇。