铁电极化调节的氧化物单晶异质结生长、光催化性能及其界面研究

This program foucses on some key scientific problems concerning the relationship between the photocatalytic property and the existing interface of oxide heterogeneous composites. It is novelty to prepare a new kind of oxide heterogeneous composites by employing single-crystal and single-domain ferroelectric PbTiO3 nanoplates as the carrier to be complexed with oxide nanocrystals of TiO2, SrTiO3 and BiPO4 with UV-responsed photocatalytic activity, where the ferroelectric polarization will used to mediate the crystal growth of the nanocrystals and the photocatalytic activity. By using hydrothermal method, the nucleation and crystal growth of the oxide nanocrystals on single-crystal and single-domain PbTiO3 nanoplates will be pursued under different reaction conditions, based on which the mediated mechanism of the ferroelectirc polarization on the oriented growth will be revealed to achieve the preparation of single-crystal heterogeneous composites by a controlled manner.Subsequently, the photocatalytic properties of the composites under UV and visible light irradation will be investigated to extand absoption and usage of the visible light range.The microstructure and interal electric field at the interfaces will be explored intensively by using atomic force microscope (AFM), high resolution transmission electron microscope(HRTEM) and aberration-corrected HRTEM, based on which the effect mechanism of interface microstructure, internal electric field and ferroelectric polariztion on the seperation of light-excited electron and hole and the photocatalytic property of the composites can be revealed. This will provide theoretical fundation and technical support for designing and developing high-performance photocatalytic materials.

针对氧化物异质结复合材料光催化性能与界面关联的一些关键科学问题，本项目创新性提出以单晶、单畴铁电PbTiO3纳米片为载体，与具有紫外光催化活性的TiO2, SrTiO3及BiPO4等氧化物纳米晶进行复合，通过铁电极化调节其界面的生长与光催化性能，获得一类新型氧化物异质结复合光催化材料；采用水热法研究不同反应条件下氧化物纳米晶在纳米片上的成核与生长过程，揭示铁电极化对其取向生长的调节机制，实现氧化物单晶异质结复合材料的可控制备；研究氧化物单晶异质结复合材料的紫外、可见光催化性能,拓展可见光的吸收与利用; 利用原子力显微镜、高分辨透射电镜及球差校正电镜等深入研究异质结界面微结构、内建电场方向与分布，揭示界面微结构、内建电场及铁电极化对复合材料光生电子、空穴的分离及光催化性能的影响规律和作用机制，为高性能光催化材料的设计开发提供理论基础和技术支持。

本项目提出利用铁电极化调节氧化物异质结外延生长、调控界面结构与单晶异质结光催化性能的新思路。以单晶、单畴铁电PbTiO3纳米片为基板，水热制备了TiO2/PbTiO3、SrTiO3/PbTiO3和BiFeO3/PbTiO3等氧化物单晶异质结材料，其界面为原子级平整，发展了一类低温、低成本制备氧化物单晶异质结的新技术；系统研究揭示了铁电正、负极性面极化屏蔽的打破与重建在异质结选择性生长、界面微结构与电子结构的调控中起到关键作用；发现了铁电极化依赖的单晶异质结高效光催化性能，阐明了界面处铁电极化对光生电子、空穴的分离机制。研究成果在Nat. Commun.、Adv. Mater.、Nano Energy、Small、ACS Applied Materials & Interfaces 等国际重要学术期刊发表SCI收录论文18篇，授权国家发明专利6项。依托本项目，培养了博士和硕士研究生7名。