能源导向的氮化物纳米复合结构构筑及其构效关系研究

Photocatalytic hydrogen generation by solar water splitting has attracted extensive research interest in the past decade because of increasing concern on renewable energy issue. To solve the low photocatalytic efficiency and the photocorrosion issues encountered by traditional photocatalysts, such as metal oxides and sulfides, we propose to construct new and complex photocatalytic nanosystems based on nitride, noble metal, and TiO2 nanocrystals. Specifically, we will optimize the composition and size of nitride nanocrystals to adjust their band position and improve optical absorption and charge transfer, the morphology and size of metal nanocrystals to control their surface plasmon and enhance optical absorption and co-catalyst, and the high index crystal facet of TiO2 nanocrystals to improve their photocatalytic activity. We plan to design and construct several complex nanosystems with different structures, and then to investigate the coupling effect, the photo-excited charge transfer process, and their effect on the photocatalytic water splitting. Finally, we hope to obtain a high efficient and stable photocatalyst based on nitride semiconductor and promote the microscopic understanding of the solar water splitting process based on the hybrid nanocrystal system.

随着能源短缺与环境污染问题日益严重，利用半导体纳米晶光解水制氢已成为纳米材料领域的前沿研究热点之一。针对氧化钛等材料的吸光有限、效率较低和镉系硫属化合物有毒、稳定性差等问题，本课题在成功制备出能带可调的高质量Ⅲ族氮化物纳米晶基础上，提出以氮化物纳米晶为基元，分别与贵金属、氧化钛纳米晶进行有序复合，系统研究复合纳米晶基元、结构与光解水性能之间的影响规律。具体将通过贵金属纳米晶的尺寸、形貌调控其表面等离极元，增强光吸收与电子注入，实现协同催化。通过不同晶面TiO2纳米晶形貌调控其表面能，提高光催化活性。通过构筑异质结型与核壳型有序复合结构，调控氮化物复合纳米晶的能带结构，系统研究有序复合结构对氮化物复合纳米晶光学吸收性能、电荷传输机制及其光解水效率的影响规律，确定氮化物复合纳米晶结构与光解水效率的构效关系，为新型复合纳米晶光催化剂的设计、制备与应用提供理论支撑和实验依据。

通过半导体复合纳米结构的有效调控实现高效光解水制氢已成为新能源、纳米材料等领域的前沿研究热点之一。本项目主要研究内容为：a）系统研究各实验条件对InN，GaN纳米晶形貌、尺寸、相结构的影响，优化得到实验条件对InN，GaN纳米晶的影响规律，实现一定程度的可控制备；b）探索贵金属和不同晶面TiO2纳米晶的生长规律，实现其尺寸与晶面的调控；c）实现各纳米基元间的复合，主要包括核壳与异质结复合纳米材料的可控制备；d）系统研究了复合纳米晶基元、结构与光解水性能之间的影响规律，有序复合结构对其光学吸收性能、电荷传输机制及其光解水效率的影响规律。本项目按照预期研究目标已经实现InN，GaN，贵金属和晶面可控TiO2纳米晶及其核壳与异质结复合纳米材料的制备。系统研究了复合纳米晶基元、结构与光解水性能之间的影响规律，有序复合结构对其光学吸收性能、电荷传输机制及其光解水效率的影响规律，为新型复合纳米晶光催化剂的设计、制备与应用提供理论支撑和实验依据。