贵金属基多元协同光催化剂的精确调控制备及其对NOx气体光催化净化作用的研究

Heterogeneous photocatalysis is a promising method for air purification because of its mild reaction conditions, low energy consumption, and less secondary pollution and so on. However, due to the poor solar-harvesting capability, low quantum efficiency, limited specific surface area, and poor recyclability of the current photocatalysts, it remains challenge for their industrial application. In this project, the noble metal-semiconductor-supports hetero-structure composite is selected as the research object, by taking the advantages of SPR effect and effective cocatalyst of noble metal nanoparticles (Au, Pt, Ru), visible light absorption of semiconductor (CdX, TiO2, Cu2O), and high specific surface area of micro/mesoporous supports (graphene, zeolite, mesoporous silica), aiming at boosting the visible light photocatalytic activity. By careful tailoring the phase compositions and investigating the influence of every phase, optimum ratios and interfacial contacts can be established to maximize visible light photocatalytic activity. Through the study of atomic structure and electronic structure of the catalyst surface/interface, we will investigate the effect of interface microstructure on photoinduced charge behavior, such as the transmission mode and direction of the photo-generated charge, and try to find the relevant controlling rule, and then further optimize carrier transmission path to realize efficient separation and migration of photoinduced electrons and holes, finally increase photocatalytic efficiency. Meanwhile, the photocatalytic mechanism of this noble metal-semiconductor-supports hetero-structure photocatalysts would be proposed by combing the results of verification experiments and theoretical simulation experiments. This project is aimed at providing theoretical support and new ideas for noble metal based multi-synergistic photocatalysts design and preparation with surface/interface microstructure control as the core.

光催化技术具有反应条件温和、能耗低、二次污染少等特点，是近年来发展起来的空气净化技术。针对现有光催化剂的较低太阳光利用率、较差的光量子产率、有限比表面积、以及纳米粉体难以循环使用限制其实际应用的关键问题，本项目以贵金属基多元协同催化材料为研究对象，利用贵金属（Au、Pt、Ru等）纳米粒子的表面等离子体共振效应及助催化剂效应，以及半导体（CdX、TiO2、Cu2O等）良好的可见光吸收特性，结合微/介孔载体（石墨烯、分子筛、介孔二氧化硅等）的高比表面积，以提高可见光催化活性为导向，基于金属-半导体-载体的表界面微结构调控构筑高效贵金属基多元协同光催化剂。同时通过有效调控载体的孔结构、孔径、比表面积、贵金属/半导体/载体界面参数，深入研究异质界面的稳定性、相容性及电荷转移机制，综合实验与理论模拟实验结果，揭示该类光催化剂的可见光NOx光催化净化机理，为其走向实用化提供相关实验数据与相应理论依据。

随着工业化快速发展，人口急剧上升，能源危机和环境污染成为人类社会的两大危机。太阳能的有效利用被认为是解决当前能源和环境问题的理想途径之一。光催化反应由于能直接将太阳能转化为化学能，降解污染，成为最有前途的光转换技术之一。光催化效率取决于光生载流子的激发、光生电子空穴对的分离和传输、活性位点上的氧化还原反应这三个过程的协同作用。因此选用能带匹配的半导体金属材料，设计贵金属-半导体光催化结构，构建光生电子的定向输运，提高光生电子-空穴的分离是最终制备出高性能光催化剂的重要途径。本项目紧密围绕项目目标，设计合成了一系列负载型贵金属基多元协同光催化剂，探索了贵金属/半导体多元光催化剂的调控规律，揭示了催化剂结构与性能之间的关联。一方面设计合成Au-CdS-rGO三元复合材料，Au@CdS核壳纳米颗粒高度分散在还原石墨烯层间，形成三明治结构，组元之间紧密的异质界面结构有效提高光生电荷分离和转移的效率。设计合成一系列Au/CdSxSe1-x异质纳米晶，精确调控异质纳米晶组分比例与Au纳米颗粒尺寸，探究贵金属/硫属化合物异质结构与光催化性能构效关系。另一方面精准调控氧化物半导体（氧化亚铜、二氧化锡）表面缺陷，探究缺陷结构与金属负载，以及二氧化氮吸附之间的构效关系，为拓展金属-半导体复合光催化剂领域的应用提供理论基础。在本项目支持下，已发表影响因子大于3.0的SCI论文15篇，申请专利1项。