新型二维异质结构界面增强光催化机理研究

Heterostructure is one of the most promising way to design photocatalytic material, since the heterostructure with interface has the ability to separate photoinduced electron and hole carrier, as well as increase the quantum efficiency of photocatalytic material. However, the physical mechanism of photocatalysis properties enhanced by heterostructure interface is still unclear, and there is a lack of systematically study on internal mechanism for the influence of interface on carrier mobility, carrier interlayer transfer, and carrier lifetime. Hence, in this project, we carry out a systematic study of several kinds of typical two-dimensional heterostructures by first-principles calculation. Due to the complex and uncertainty of interface, we will comprehensively explore the effects of interface interaction strength, interface polarization, and interface contact barrier on the carrier mobility, carrier interlayer diffusion, and carrier lifetime. It is expected to reveal the physical mechanism of photocatalysis properties enhanced by two-dimensional heterostructure interface. Following this, the external approaches such as doping, defect, external strain, water environment, and built-in electric field are applied to regulate the behavior of carrier, which aims to propose a scheme of synergistic effect to enhance the photocatalytic efficiency. Through this project, we wish to have a breakthrough in revealing the intrinsic mechanism of photocatalysis properties enhanced by two-dimensional heterostructure interface, and it is expected to provide scientific and technical basis to design photocatalytic material with higher efficiency.

异质结构是一类极具前景的催化体系，其异质界面可为光生电子-空穴对的分离、量子效率的改善提供有效增益。然而，其界面增强光催化机理，特别是界面对载流子迁移率、载流子层间传输、载流子寿命等影响的内在机制尚缺乏系统性研究。本项目拟以几类典型二维异质结为研究对象，系统探究界面耦合强弱、界面极化电场、界面接触势垒对光生载流子迁移率、载流子层间传输特性、载流子寿命等的影响规律，明晰二维异质结界面增强光催化量子效率的内在物理机制，并在此基础上施以掺杂(缺陷)、应力应变、外界环境及内建极化电场等调控手段，提出界面增强光催化效率的可行性方案，为进一步提高二维异质结构的光催化效率提供理论依据。

异质结构是一类极具前景的催化体系，其异质界面可为光生电子-空穴对的分离、量子效率的改善提供有效增益。然而，其界面增强光催化机理，特别是界面对载流子迁移率、载流子 层间传输、载流子寿命等影响的内在机制尚缺乏系统性研究。本项目拟以几类典型低维纳米材料及其异质结构为研究对象，系统研究纳米结构尺寸、不同界面对结果电子特性及载流子迁移的影响，发现异质结构表现出优越的电学性能，如电子载流子迁移率为281.28 cm2•V−1•s−1，空穴载流子为3951.2 cm2•V−1•s−1；在此基础上，考虑不同界面耦合作用对结构的内建电场、空间电荷分离、载流子迁移特性以及几类典型光催化反应的影响规律，发现利用极性材料构建MoSSe/GaN异质结不仅能有效增强载流子分离，而且其表现出独特的可见-红外光解水活性；最后，探究了掺杂，缺陷等调控手段，发现了氧空位或间隙钛缺陷在光催化分解水和二氧化碳还原中的不可或缺作用，以及间隙态Mo能够有效降低光解水所需的能垒。通过本项目的实施，我们提出界面增强光催化效率的可行性方案，为进一步提高二维异质结构的光催化效率提供理论依据。