缺陷型助催化剂诱导半导体光生电荷分离研究

Electron-hole recombination in semiconductor is a challenging problem in the field of photocatalytic research. Recently cocatalyst modification of semiconductor can efficiently promote the charge separation and transfer in photoelectrochemical water splitting. However, the solar water splitting performance is still limited by several factors, especially, lower catalytic activities of cocatalysts, barrier in the interface between cocatalyst and semiconductor, limiting the photogenerated hole fast transferring to the interface. In this study, we focus on the defect engineering on oxygen evolution reaction cocatalysts to improve the water oxidation activity of visible-light semiconductors through adjusting the defect type and concentration, optimizing the interface between cocatalyst/semiconductor, et al. The in-situ synchronous illumination X-ray photoelectron spectroscopy (SIXPS) and theoretical calculation introduced in this work further examine the surface chemical composition, valence states elements, and electronic structure on the defective cocatalysts decorated on semiconductors. We believe that this project provides a novel strategy and concept to form highly efficient photoanodes for solar water splitting.

半导体材料光生电子-空穴易复合是目前光催化研究领域非常具有挑战的难题。助催化剂修饰半导体纳米材料可有效促进光生电荷分离和催化转化。然而目前所使用的助催化剂仍然存在催化活性较低，助催化剂与半导体界面存在一定势垒，阻碍光生电荷快速分离与迁移，进而影响半导体分解水效率。本项目拟在对可见光响应的半导体材料表面构筑缺陷型析氧助催化剂，通过在助催化剂中制造缺陷，调整缺陷类型与浓度，改善助催化剂与半导体界面，进而增加助催化剂活性位点，提高半导体中载流子快速分离与传输性能。利用原位X射线光电子能谱技术和理论计算等手段深入研究缺陷型助催化剂对半导体光生电荷分离的驱动因素，获得载流子分离的微观作用规律，为进一步开发与拓展高效光催化性能的半导体材料提供新思路与新概念。

本项目分别对可见光响应半导体材料表面构筑缺陷型析氧助催化剂，通过调控助催化剂缺陷类型和浓度，增强了催化剂活性位点，改善助催化剂与半导体界面，提高半导体中载流子快速分离与迁移性能，进而提高可见光响应半导体光电催化活性及稳定性。利用准原位测试技术等手段研究了缺陷型助催化剂对半导体光生电荷分离的影响因素，获得了载流子分离微观作用规律。这一工作为开发和拓展新型光电催化半导体材料提供了借鉴。