基于Jahn-Teller效应的Bi4Ti3O12/CuFe2O4铁电复合材料p-n结界面调控机理及光催化性能研究

Ferroelectric Bi4Ti3O12 (BTO) has been receiving wide attentions owing to its excellent photocatalytic activity in handling the challenges of energy shortage and environmental pollution. However, its narrow light response range and low photo-generated carrier migration efficiency are limiting the further improvement of its photocatalytic performance. Therefore, in this project a p-type semiconductor with a narrow bandgap, CuFe2O4 (CFO) is selected to combine with n-type BTO to form a p-n junction and expand the light response range. Meanwhile, based on the Jahn-Teller (J-T) effect in CFO, the p-n junction interface will be regulate to enhance the ferroelectric polairization in BTO and then boost charge carriers separation. Through clarifying the formation mechanisms of p-n junction, the relationships among J-T effect, p-n junction interface and ferroelectric spontaneous polarization will be investigated, and the dependence of the photo-generated carrier migration behaviors on the interfacial regulation will be studied as well. Furthermore, the mechanisms of interfacial regulation and enhanced ferroelectric spontaneous polarization electric field will be explored. The synergetic effect of the p-n junction interfacial built-in electric field and ferroelectric spontaneous polarization electric field on the charge carrier migration will be established. Finally, the influence mechanism of interfacial regulation on the photocatalytic performance of BTO/CFO composite materials will be revealed. This project is expected to give a clue for developing other ferroelectric composite photocatalytic materials with excellent performance.

铁电材料Bi4Ti3O12(BTO)因优异的光催化活性可有效解决当今能源短缺和环境污染等问题备受关注，而有限的光谱响应范围和低的光生载流子迁移效率是影响其光催化性能的关键因素。针对此问题，本项目基于p型CuFe2O4(CFO)的窄带隙特性拓展光谱响应范围和Jahn-Teller(J-T)效应调控界面增强光生载流子迁移效率，提出构筑p-n结型BTO/CFO铁电复合材料并采用界面调控提高光催化性能的新思路。项目将深入研究p-n结的形成机理，探讨J-T效应、p-n结界面与铁电自发极化内电场间的关联性，分析p-n结界面调控对光生载流子迁移行为的影响规律，揭示基于J-T效应的p-n结界面调控机理和铁电自发极化内电场增强机制，构建光生载流子在p-n结界面内建电场和铁电极化内电场协同作用下的迁移模型，确立J-T效应调控p-n结界面对光催化性能的影响机制，为其他高性能铁电复合光催化材料的研发提供理论依据。

铁电材料Bi4Ti3O12因独特的光催化活性可有效解决当今能源短缺和环境污染问题备受关注，而有限的光谱响应范围和光生载流子迁移效率是限制其工业化应用的关键因素。因此，本项目基于CuFe2O4独特的姜-泰勒效应、g-C3N4和AgBr等材料的窄带隙拓展光谱响应范围和复合界面调控增强光生载流子迁移效率等原理，开发了一系列操作简便、成本低廉的合成工艺，构筑了一系列具有优异可见光光催化活性的Bi4Ti3O12基复合材光催化材料，包括Bi4Ti3O12/CuFe2O4复合纳米管、Bi4Ti3O12/Ag/g-C3N4异质结和Bi4Ti3O12/AgBr异质结。项目通过深入的科学实验和理论技术详细地揭示了各个复合材料体系的形成机理、异质界面调控与光催化活性的关联性以及光生载流子在界面处的迁移动力学机制。项目的开展能够对今后利用界面调控增强光催化性能的策略而研发高性能复合可见光光催化材料具有重要的科学意义和参考价值。