光生电荷可隧穿的“单点单核金属/绝缘体/半导体”SMIS结型复合光催化剂及其作用机制研究

研制新型高效光催化剂，突破光能转换低效率瓶颈是光催化研究面临的巨大挑战。本项目基于前期探索研究和发现，聚焦水分解制氢和用水还原CO2制化学品和太阳能燃料等重大能源光催化过程，另辟蹊径，提出光生电荷可隧穿分离输运的多组分异质复合光催化剂设计新原理和新思路。研究不同组成和类型的“单点单核金属/绝缘体/半导体”SMIS异质结构的控制制备与光催化性能调控；探索水分子在单点单核金属空穴捕获中心上的氧化与O-O键的形成机制以及CO2在单点单核金属电子捕获中心上的吸附、活化和还原转化的分子机理；确定电荷隧穿分离输运的关键影响因素。制备出高活性和高稳定性的SMIS结型复合光催化剂，弄清界面多电荷转移反应的化学机制，阐明SMIS结型光催化剂功能组元结构和性能的设计原理，揭示界面电场对电荷隧穿输运的调控规律。该研究对丰富半导体光催化基础理论以及指导新型高效能源转化光催化剂的设计制备具有重要的科学和实际意义。

Developing new high-efficiency photocatalysts to break through the bottleneck of low energy conversion efficiency is a huge challenge in the field of photocatalysis. Based on our previous exploration and discovery, this project aimed at the photocatalytic processes of major energy sources such as water splitting into hydrogen and CO2 reduction to chemicals and solar fuels, and proposed a novel idea and principle for designing multi-component heterogeneous photocatalysts with the tunneling, separating, and transport properties of photogenerated charges. Main researches focused on three aspects. The first part is the controlled preparation and regulated performance of “mononuclear single-atomic metal/insulator/semiconductor (SMIS)” heterojunctions with different compositions and types. The second part is to explore the elemental processes of water oxidation occurred on the electron-trapping center of mononuclear single-site metal atoms, the formation mechanism of the O-O band, the absorption, activation and reduction processes of CO2 substrate on the hole-trapping center of mononuclear single-site metal atoms. The third part is to clarify the key parameters affecting the charge tunneling, separation and transport. The SMIS-type photocatalysts with high activation and stability will be prepared successfully. The chemical mechanism of interfacial multi-charge-transferred reactions will be uncovered clearly. The design principles of functional motif, structure and performance of SMIS-type photocatalysts will be clarified. The regulation rule of interface electric field on the tunneling and transport photogenerated charges will be revealed. This research was of scientific importance and practical significance for enriching the basic theory of semiconductor photocatalysis and guiding the design and preparation of new high-efficiency energy conversion photocatalysts.