内建电场的构建与调控提高Bi2MoO6光催化剂量子效率的实验和理论研究

Bi2MoO6 is regarded as a promising material in the field of photocatalysis owing to its advantages of good visible-light response activities, good stability, low cost and so on. Combining with its structural characteristics, the build and control of internal electric fields is used to improve the quantum efficiency of Bi2MoO6. By experiment and theoretical calculations, the exploration of how to build and control internal electric fields in the Bi2MoO6 single phase is studied by the crystal facets engineering of polar surface and the surface functionalization. The mechanism of the build of internal electric fields in the heterostructured photocatalysts is investigated by examining the structures and properties of the interfaces between Bi2MoO6 and p-type semiconductors, which can be used for designing high efficient Bi2MoO6 based p-n heterostructured photocatalysts. Based on the above work, the transfer law of the photo-generated carries in Bi2MoO6 and the mechanism of the transfer and separation of the photo-generated carries affected by internal electric fields are investigated and revealed . It will shed a light on the synthesis of Bi2MoO6 photocatalysts with high quantum efficiency.

Bi2MoO6光催化材料具有可见光活性、稳定性好、成本低廉等优点，在光催化领域表现出广阔的应用前景。为了进一步提高Bi2MoO6光催化剂的量子效率，结合其自身结构特点，本项目提出利用内建电场的构建和调控提高Bi2MoO6光催化剂的催化性能。拟采用理论和实验相结合的方法，通过对Bi2MoO6单相光催化剂极性面的晶面工程和表面功能化的研究，探索单一相Bi2MoO6光催化材料的内建电场的构建和调控手段；通过研究Bi2MoO6和p型半导体光催化材料复合界面的结构特性，揭示异质结界面结构诱导内建电场的机理，指导设计高效的Bi2MoO6基p-n型异质结。在此基础上，考察内建电场作用下Bi2MoO6光催化剂内光生载流子的迁移规律，阐明内建电场影响光生载流子迁移与分离的机制，为制备合成具有高量子效率的Bi2MoO6光催化剂提供新思路。

为了进一步提高Bi2MoO6光催化剂的性能，本项目研究工作从Bi2MoO6自身结构特点出发，采用理论和实验相结合的方法，探索和研究了利用内建电场调控改善Bi2MoO6催化性能的方法。首先，利用不同的表面活性剂实现了Bi2MoO6单相光催化剂的晶面和形貌调控，具有(010)极性面暴露的Bi2MoO6超薄纳米片表现出较高的光催化活性，通过理论计算考察了极性面诱发内建电场的机理。其次，利用第一性原理计算方法研究了Bi2MoO6基 (BiOCl/Bi2MoO6, BiOI/Bi2MoO6) p-n型异质结光催化剂的界面微观几何和电子结构，考察了异质结的稳定性和组分间的能带匹配关系，揭示了异质结界面结构诱导内建电场的机理；在此基础上，利用水热法制备合成了BiOCl/Bi2MoO6和BiOI/Bi2MoO6异质结光催化剂，并通过调控两种组分比例探索了最佳反应体系。最后，结合实验和理论结果分析了内建电场影响光生载流子迁移与分离的机制，我们发现Bi2MoO6单相光催化剂内存在沿[010]方向的内建电场，BiOCl/Bi2MoO6和BiOI/Bi2MoO6异质结界面处可形成由n-Bi2MoO6指向p-BiOCl(或p-BiOI)的内建电场，光生载流子在内建电场的作用下可发生定向迁移，从而促进光生载流子的分离。本项目的研究工作为制备合成具有高效光催化性能的Bi2MoO6光催化剂提供了指导和参考。