基于等离子体诱导电荷分离效应的可见光全分解水催化剂的构建及机理研究

One of the most appealing ways to resolve the worldwide energy crisis and environmental pollution is converting solar energy into hydrogen energy through water splitting. Highly effective and stable photocatalysts lie at the heart of the energy conversion from solar to hydrogen. This project will focus on the development of novel photocatalysts based on plasmon-induced charge separation effect, in which Ag@Au/TiO2 is used as host photocatalysts controllably loaded with both co-catalysts for hydrogen and oxygen evolution, and hydrogen selective membrane (Cr2O3). The as-designed photocatalysts with tailored structures are expected to have high catalytic activity and stability, wide visible-light-response and high solar-to-hydrogen conversion efficiency. We will investigate the effect of microstructure of photocatalyst on the activity of overall water splitting, explore the promotion of the co-catalysts and hydrogen selective membrane for overall water splitting, and promulgate the mechanism of the charge separation and transfer, surface reaction in the process of overall water splitting. This project is expected to provide valuable reference and guidance for designing new photocatalyst for overall water splitting.

光催化分解水制氢，将太阳能转换成氢能，被认为是解决能源短缺和环境污染问题的最佳途径之一，其核心是研制高效稳定的可见光催化材料。本项目基于等离子诱导电荷分离(PICS)效应，拟以Ag@Au/TiO2为主催化剂，同时精准可控地光沉积产氢和产氧双助催化剂，并在产氢助催化剂上包覆一层透氢阻氧的Cr2O3膜来防止生成水的逆反应。通过调控制备工艺参数，构建结构和组成精确可控、稳定、宽光谱响应、高效的新型可见光全分解水催化材料(CoPi-Ag@Au/TiO2-Pt@Cr2O3)。研究所制备的催化剂中TiO2的微观结构、Ag核的尺寸、Au壳的厚度和助催化剂的负载量与可见光全分解水产氢性能的关系，建立合理的构效关系模型；探究助催化剂及氢选择性透过膜层对全分解水性能的促进作用，揭示全分解水反应过程中电荷分离、迁移及表面反应等微观机制，为高效全分解水催化剂的设计与应用提供重要科学依据与技术基础。

随着能源短缺和环境污染问题日益严重，清洁能源的开发利用越来越受到人们的重视。光(电)催化分解水制氢，将太阳能转换成氢能，是解决能源短缺和环境污染问题的理想途径之一，其核心是开发高效稳定的可见光催化剂。因此，本课题基于贵金属-半导体界面的等离子诱导电荷分离(PICS)效应，以贵金属/半导体为主催化剂，同时精准可控地沉积助催化剂，通过调控制备工艺参数，构建结构和组成精确可控、稳定高效的新型可见光催化材料。通过各种表征方法，证实基于PICS的光沉积法可以成功将助催化剂磷酸钴盐(CoPi)精准沉积到Au纳米颗粒表面，形成Au@CoPi的核壳结构。所制备的TiO2/Au@CoPi比TiO2/Au具有更大的光电流，更明显的光电势变化和更小的界面电荷转移电阻，因而说明CoPi的沉积对光催化分解水产氢具有较大促进作用。同时，还提出了TiO2/Au@CoPi分解水反应过程中电荷产生、分离和迁移等微观机制。除此之外，高分散的Au纳米颗粒修饰的WO3等离子体催化剂也被开发并应用到分解水制氢，该催化剂同样表现出较为优异的光电化学性能。本项目的研究结果将为高效分解水催化剂的设计与应用提供重要科学依据与技术基础。