光催化材料中微观应变与光物理化学特性的相互作用研究

As one of the important structural parameters, strain has been studied for many years in the modification of the optical properties and electronic structures of semiconductor materials. And recently, the studies of the strain-controlled electrocatalytic properties of metallic materials have shown that stain can efficiently tune the electrochemical performance. Although there are many researches on the strain engineering of the properties of the materials, there are few that focus on the effect of strain on the synergistic photophysical and photochemical properties of semiconductors. This project aims to investigate the effect of microstrain on the photophysical and photochemical properties of photocatalytic materials. In this purpose, microstructure design and temperature field regulation are used to induce tunable internal strain in the photocatalytic materials. The effect of the strain on the band structure, electronic structure and chemical reaction activity of the photocatalytic materials will be systematically investigated. Based on this research, the relationship between microstrain and the synergistic photophysical and photochemical properties of the photocatalytic materials will be established. The material composition, structure and processing parameters will be optimized to modify the photocatalytic materials through strain engineering, so to get higher photocatalytic activity. This new technology may be beneficial for the rational design of the photocatalytic materials and the photoelectrochemical stress sensor in the future.

应变作为材料重要的结构参数之一在半导体材料光学性能以及电子结构调控方面已有多年的研究，近年来，金属材料电催化性能的应变调控研究表明应变能够显著改善材料的电化学性能。尽管人们在应变调控材料性能方面已进行了一定的研究，但应变对半导体材料光物理化学性能的协同作用研究仍较为薄弱。本项目拟利用材料微结构设计及温度场调控在光催化材料中引入微观应变，并系统研究微观应变对光催化材料能带结构、光生载流子迁移机制、光反应活性物质相互作用关系等的影响。基于此，建立微观应变与光催化材料光物理化学性能的协同作用关系，进一步获得微观应变与光催化性能的影响规律，并期望得到微观应变调控改性光催化材料的设计理论与准则，实现光催化效率的优化。研究成果对于未来新型光催化材料及光电化学应力传感器的研制提供理论与实验支持。

光催化技术能够将光能转换为化学能，在解决全球变暖，环境污染以及新能源方面表现出了广阔的应用前景。本课题通过对材料的微结构设计，在光催化材料中引入微观应变，研究了微观应变与材料光催化性能的影响规律。成功设计制备了ZnO/GaN固溶体纳米纤维，CaTa2O6/CaTaO2N/Ta3N5复合纳米纤维，块体C3N4，Mo掺杂C3N4等光催化材料。通过对ZnO/GaN固溶体纳米纤维表面锌含量的调控，获得了具有表面拉应力的纳米纤维，表现出了增强的光催化性能，其中，成分差异达30%的纳米纤维具有最好的光催化性能，反应速率常数达0.058 min-1；通过缺陷结构的调控在CaTa2O6/CaTaO2N/Ta3N5复合纳米纤维中引入微观应变，获得了增强的光催化性能，表观量子效率达17%；通过调节氮化碳表面氢结构，获得了比目前文献水平高一至两个数量级的反应速率常数；进一步通过在氮化碳中掺杂钼，发现了一种降低了氮化碳的煅烧温度，同时获得了增强的光催化性能的方法。