镍钴基电催化剂/硅复合光阳极的表面缺陷调控及其光电化学分解水性能研究

Silicon (Si) has emerged as a promising photoanode candidate in photoelectrochemical (PEC) water splitting. However, the practical application of Si is limited by its proneness to photo-corrosion and sluggish surface reaction rate. Surface modification electrocatalysts is proved to be an effective way to improve the photoanodes efficiency and stability. Current studies mainly focus on regulating the content, structure and loading methods of electrocatalysts, whereas the importance of defective electocatalysts that profoundly influence the oxygen evolution reaction (OER) performance of Si photoanodes is often neglected. Meanwhile, the influence mechanism is also unclear. In this project, the effect of the defective electocatalysts on the band structure of Si semiconductor was firstly verified by density functional theory (DFT) calculation. Afterwards, the Ni/Co based electrocatalysts decorated Si photoanodes will be prepared via a simple and low cost electrochemical method based on previous works. Heteroatomic doping, plasma etching and thermal treatment approaches are employed to create vacancy defects on electrocatalyst to improve the OER performance of Si photoanodes. The effect of electrocatalysts with various types and concentrations of defects on the OER activity of silicon photoanodes will be investigated to reveal the relationship between defects and electrochemical performance. Moreover, the mechanism of improving the performance of Si photoanodes with defective electrocatalysts will be clarified based on DFT calculation data. The goal of this project is to fabricate low cost, high activity and high stability silicon photoanodes, which is beneficial to provide a novel insight and direction for design of high performance silicon-based devices.

硅半导体是光电化学电池(PEC)分解水阳极材料的研究热点，但硅极易发生光腐蚀及迟缓的表面反应速率限制了其应用。负载电催化剂是改善硅光阳极活性及稳定性的有效途径，而对电催化剂的研究集中在含量、结构及负载方法的调控，鲜有工作探讨缺陷型电催化剂对硅阳极析氧性能的影响，其影响机理也不明确。本项目首先通过密度泛函理论(DFT)证明缺陷型电催化剂可以改变硅能带结构，再在前期研究基础上通过低成本、易操作的电化学法制备镍/钴基电催化剂负载的硅光阳极。为提高硅光阳极活性，分别采用异原子掺杂、等离子体刻蚀和热处理法在电催化剂上引入空位缺陷，探究含不同类型及浓度空位的电催化剂对硅光阳极析氧性能的影响，进而揭示缺陷与硅器件光电性能之间的关系。结合DFT计算阐明缺陷型电催化剂提高硅光阳极性能的机理。通过本项目的实施，期望制备出低成本、高活性及高稳定性的PEC硅光阳极，为高性能硅基器件的研发及应用提供新思路与途径。

本项目通过低成本、易操作的电化学法成果制备了高活性和高稳定性的缺陷型Ni基电催化剂负载的硅光阳极。分别采用化学异原子掺杂法和热处理法在电催化剂或光阳极上引入空位缺陷，并探究了不同类型缺陷的电催化剂对硅光阳极析氧性能的影响；结合DFT理论计算分析了电催化剂上的缺陷对硅半导体能带结构及界面的影响。此外，本项目还探讨了空位对钒酸铋光阳极的影响，并探讨了二维异质结催化剂在阴极的析氢反应中的研究。本项目已按预期完成了研究目标，项目执行期内共正式发表高水平文章10篇。