锡系层状多元氧化物的湿化学合成及光催化净化性能研究

Photocatalytic environmental remediation technology could make use of solar energy to degrade organic pollutants and disinfect water pathogens. The main challenge in this research area is to develop photocatalysts with enhanced performances under visible light illumination to solve two problems faced by current photocatalysts on the narrow light response range and the low electron-hole separation efficiency. Because their layered structure was found to be beneficial for charge carrier separation, tin-based layered multi-oxides (like niobates and tantalates) have attracted much attention for photocatalytic applications of water-splitting and environmental remediation in recent years. However, the majority of methods used for preparing tin-based layered multi-oxides are still based on solid-state reactions, which are prone to produce impurity phases and make it difficult to modulate the crystal structure, electronic structure and optoelectronic properties of photocatalysts. This proposed project is based on our previous work on photocatalysts for environmental remediation, in which tin-based layered multi-oxides will be developed by the wet chemistry synthesis processes to obtain tunable crystal structures and defect types. In this proposed project, the interactions between light and photocatalysts, and between photocatalysts and environmental pollutants will also be investigated to deepen our understanding of the working mechanism of these tin-based layered multi-oxides photocatalysts, which could provide general directions for the design, synthesis and application of visible-light-activated photocatalysts.

光催化净化技术能利用太阳能分解环境中的污染物、杀灭病原体，被认为有可能替代传统净化技术，其发展的关键在于开发高效可见光光催化材料并加深对材料与污染物相互作用机制的认识。近年来，锡系层状多元氧化物功能陶瓷被认为是一类极具潜力的具有良好光生电荷分离能力的可见光光催化材料。然而，现阶段制备该类材料的湿化学方法还不成熟，通常采用的固相法既易于生成杂质相，同时也不利于调控该类材料的晶体结构。本研究拟借助申请人及其所在团队在光催化材料制备与应用探索方面的经验，采用湿化学合成方法，通过晶格调控和缺陷调控来发展锡系层状多元氧化物可见光光催化材料，进而研究该类功能陶瓷材料光催化净化污染物的作用机制，研究光与材料、材料与污染物之间相互作用的基本规律与原理，反馈材料设计合成，为光催化技术应用于环境修复领域创造条件。

近年来科研工作者从多个方面对光催化材料进行了深入研究，发展出系列高效可见光光催化材料，研究思路包括对宽禁带半导体进行掺杂、对不同能带结构的半导体进行能带匹配的复合以及缺陷调整等等。但是掺杂与异质结界面的引入会带来新的问题，比如带来新的光生电荷复合中心、增加光生电荷的扩散距离等等，不利于整体光生电荷利用率的提高。因此，如何兼顾材料的光吸收以及光生电荷的利用率仍然是高效光催化材料设计中亟需解决的关键科学问题。本项目以锡铌多元氧化物为切入点，发展新型可见光光催化材料，通过湿化学设计，调配出不同的前驱体反应溶液，结合不同温度处理，可制备出系列锡基、铌基多元氧化物，通过合成工艺参数的设计，发展出多元氧化物固溶体材料、铌酸锡基多元氧化物材料及其他类型铌酸盐光催化材料，该系列光催化材料由于自身结构的特点，具有自发分离光生载流子的能力，无需牺牲剂即有不俗的光催化性能，为新型光催化净化材料以及二氧化碳光催化还原材料的设计提供新的思路。