非金属共掺杂纳米CeO2的可见光催化性能及其高压研究

Water pollution, especially the serious pollution of dye wastewater is a major environmental problem，which needs to be solved at present. In recent years, the research on doped-semiconductor photocatalyst has become a hot topic, owing to its novel ability of degradation organic dye pollutants. However, low utilization rate of solar light and rapid electron-hole recombination rate affect its applications. Furthermore, the interaction between impurity and matrix material and its influence mechanism on the photocatalytic properties is an open question. In this project, nonmetals co-doped CeO2 nanomaterials will be synthesized by hydrothermal/solvothermal route combining high temperature thermal diffusion technique, and their visible-light photocatalysis will also be studied, which could provide a valuable guidance for the fabrication of new functional materials. Moreover, in order to illuminate the interaction between impurity and matrix material and its influence mechanism on the photocatalytic properties, in-situ high pressure studies will be carried out on the co-doped CeO2 nanomaterials. Using high pressure tools, we can investigate the influencing factors on the photocatalytic performances of CeO2 nanomaterials in terms of molecular (atomic) interaction, revealing the physical essence of the impurity-effect on photocatalytic performance. This project will be of great interest from both a fundamental and a practical point of view.

水污染，尤其是染料废水的严重污染是目前人们亟待解决的重大环境问题。近年来，以降解废水中有机染料污染物为目标的掺杂型半导体光催化材料的制备和性能研究成为热点。然而，对可见光极低的利用率和光生电子-空穴对极高的复合率是制约其实际应用的瓶颈；而且，杂质与基质材料之间的相互作用及其对材料光催化性能的影响机制尚未清楚。本项目利用水热/溶剂热法与高温热扩散法相结合，制备出非金属共掺杂纳米CeO2光催化材料，研究其对有机染料污染物的可见光催化性能，探索提高其可见光催化效率的途径；利用高压原位实验研究非金属共掺杂纳米CeO2在高压下的原子排布、杂质能态和光学性能的变化规律，从分子（原子）层面研究其可见光催化性能的影响因素，揭示杂质影响纳米CeO2光催化性能的作用机理。该工作不仅对于设计新型光催化材料具有巨大的应用价值，而且对于揭示影响材料性能的物理本质具有开创性意义。

本项目研究中，选取Ce(NO3)3·6H2O作为铈源，TEA作为氮源，葡糖糖作为碳源，氧化石墨作为载体，利用水热、溶剂热方法成功制备出具有特殊暴露面CeO2纳米材料，掺杂CeO2纳米材料以及石墨烯负载CeO2纳米材料；利用亚甲基蓝作为目标降解物，研究了不同CeO2纳米材料在紫外以及可见光条件下的光催化性能，研究发现，通过包覆、掺杂以及形貌调制等手段可以大大提高CeO2纳米材料的光催化性能；还研究了CeO2纳米片的压致相变行为，研究发现，与CeO2体材料相比，其结构稳定性大大提高。系列研究工作丰富了我们对纳米CeO2光催化性能及压致相变行为的深入认识和理解。同时我们还进行拓展研究，发现限域于石墨烯片层/氮化硼片层间的A7聚合氮、以及限域于h-BN片层间的N8聚合氮能够稳定存在于常温常压条件下，且在450-600K的温和条件下即可实现放能，远远低于其他限域体系（1400K以上，甚至5000K）。深入分析表明，其稳定存在及温和放能的物理机制是主客体间存在较小的电荷转移量。上述研究成果授权国家发明专利2项，发表SCI论文3篇，在投论文2篇。