ZnO光催化还原CO2机理探索及高效催化剂结构设计与制备

ZnO是一种潜在的高效CO2还原光催化剂，然而作为提高光催化效率和选择性的基础，对其光催化还原的反应路径和机理的研究还基本上处于空白。因此，申请人立题以大尺寸的ZnO体单晶为基础，利用单晶结构确定、性能稳定可测、缺陷可控以及可以获得单一晶面的样品等优点，构建尽可能接近理论理想状态的模型反应体系，对ZnO光催化还原CO2的微观机制进行系统研究。具体以不同晶面指数的理想单晶面为基础，引入晶格缺陷、表面金属负载等多种影响因素，揭示各因素对CO2和H2O或H2分子的吸附构型、活性位点、反应中间体乃至反应路径起作用的微观机制。重点理清吸附状态、活性位点、反应中间体以及反应最终产物之间的相互关系。本项目研究结果可以从分子尺度阐明ZnO光催化还原CO2的反应路径，揭示晶面指数、表面缺陷、金属负载对催化反应路径和效率的影响机制，为今后设计与合成具有高催化活性、高选择性的纳米催化剂提供理论指导。

ZnO is a potential high-performance photocatalyst for CO2 reduction. However, as the cornerstone for improving the efficiency and selectivity of photocatalysis，the reaction pathways and mechanisms for photocatalytic CO2 reduction on ZnO is rarely investigated. Therefore, we proposed to systematically investigate the microscopic mechanism of photocatalytic CO2 reduction on ZnO surface, in virtue of the merits of defined crystal structure, stable and measureable properties, controllable defects and the feasibility to obtain samples with specific exposed crystal surfaces for bulk single crystals，which could be used to construct theoretically ideal model reaction system. In detail, the ideal single crystal surfaces with different miller indices were chosen as research subjects, and then the factors of crystal defects and metal nanoparticle loading were taken into account. The effects and its microscopic mechanism of the above experimental conditions on the absorption configurations of CO2 and H2O/H2, active sites, reaction intermediates and even the reaction pathways will be studied. This project is aimed to disclose the effects of the factors of crystal indices, surface defects and metal loading on the reaction pathway and efficiency of the photocatalytic CO2 reduction. The obtained research results will provide theoretical foundation for the future design and synthesis of nano-photocatalyst with high efficiency and high selectivity.