应用于环境治理的具有“记忆”效应的高效可见光光催化材料研究

Since the discovery of photoelectrochemical splitting of water on n-TiO2 electrodes by Fujishima and Honda in 1972, semiconductor-based materials have been investigated extensively as photocatalysts for environmental applications. Recent development has been focused on the development of photocatalysts that can yield high reactivity under visible light so that a greater portion of the solar spectrum may be used to provide photocatalytic capability. However, they lose their photocatalytic capability in the dark environment, where they could not produce electron and hole pairs anymore. It had been found by the proposer that some visible-light-activated photocatalysts can store part of their photocatalytic activity in “memory” so that once the photoexcitation is turned off, they could still remain active for an extended period of time. This proposed project is based on our previous work on photocatalysts with “memory” effect. In this proposed project, novel photocatalysts with “memory” effect will be developed upon deepening the understanding of the working mechanism of photocatalytic “memory” effect. By modulating the material composition, component ratio, and size and space distribution of energy storage component in these photocatalysts, their photocatalytic “memory” effect could be optimized to obtain enhanced intensity, efficiency, and duration time of activity when the illumination is turned off. Thus, highly efficient, visible-light-activated photocatalysts with “memory” effect could be developed with better performance and lower cost, which could have the potential for a broad range of environmental applications.

自1972年Fujishima和Honda报道光催化分解水以来，光催化已经在环保领域得到了广泛的研究。可见光光催化材料可以大大提高对于太阳光能的利用效率，近年来成为光催化材料发展的热点。然而，在外界光源停止照射后，电子－空穴对不能继续产生，材料的反应活性迅速丧失。申请人发现，材料能够通过光催化“记忆”效应储存其在光照条件下产生的部分反应活性，并在光照关闭后一定时间范围内保持这种反应活性。本项目拟在申请人前期光催化“记忆”效应研究的基础上，发展出多种新型具有“记忆”效应的光催化材料体系，进一步发展对于光催化“记忆”效应机制的理解，通过材料设计（包括成分、组元比例、储能组分尺寸与空间分布等方面）来优化与调控“记忆”效应强度、效率与持续时间，控制存储光能的释放，获得性能更为优异、成本更低的具有“记忆”效应的高效可见光光催化材料体系，从而为光催化技术进入环境治理实际应用进一步创造条件。

自1972年Fujishima和Honda报道光催化分解水以来，光催化已经在环保领域得到了广泛的研究。可见光光催化材料可以大大提高对于太阳光能的利用效率，近年来成为光催化材料发展的热点。然而，在外界光源停止照射后，电子－空穴对不能继续产生，材料的反应活性迅速丧失。申请人的前期研究工作发现，材料能够通过一种光催化“记忆”效应储存其在光照条件下产生的部分反应活性，并在光照关闭后一定时间范围内保持这种反应活性。本项目中，申请人通过进一步研究发展出两类具有光催化“记忆”效应的新型光催化材料体系，即含具备电子存储/释放能力的变价元素组元的纯相可见光光催化材料体系与含有具备电子存储/释放能力的变价元素掺杂的单相光催化材料体系，发展出一种定量测试光催化“记忆”效应效果的光电化学方法，发现了一种通过光催化“记忆”效应实现光致伸缩的全新机制。这些研究成果说明，具有光催化“记忆”效应的材料选择范围可以大大拓展，光催化“记忆”效应的研究空间非常广阔。光催化“记忆”效应不仅能应用于绿色全天候环境净化领域，还可以通过它改变材料的电子结构，从而实现光照对不具有相应光致变化能力的材料物性（晶体结构、光、电、磁、热等）的调控。这是一种通过光场调控功能材料性能的新思路，有望发展出多种新型光调控功能材料与器件，非常值得进一步深入研究。