光电化学分解水制氢用Cu2O基光电极的晶体取向和界面结构的协同调控

Cu2O as a p-type semiconductor is considered to be a very promising material to construct photocathode for photoelectrochemical water splitting. However, Cu2O based photocathodes always suffer from serious photocorrosion. The fast transport and transfer of photoexcited charge carriers in Cu2O is essentially important to suppress the photocorrosion. In this project, we proposed a new strategy to promote the transport and transfer of photoexcited charge carriers by synergistically controlling crystallographic orientations and interface structures of Cu2O photocathodes. In order to enable a fast transport of charge carriers from bulk to surface of Cu2O, the oriented growth of Cu2O crystals along with the highly conductive direction is controlled by an electrochemical deposition method. On the other hand, an ohmic contact is to be targeted at the interface between the current collector and Cu2O, and a pn junction with good interfacial lattice match is to be constructed at the interface of Cu2O/electrolyte. The holes and electrons reaching the surfaces of Cu2O can be effectively transferred to counter electrode and the n-type part of pn junction, respectively. By doing these designs, it is anticipated that a fast transport and transfer of charge carriers and thus suppression of photocorrosion of Cu2O can be realized. Co-catalysts for hydrogen evolution will be loaded on the above designed Cu2O photocathode to improve photoelectrochemical water splitting efficiency by lowering reaction barriers. This study will clarify the mechanisms and general rules of promoting the transport and transfer of photoexcited charge carriers by synergistically controlling crystal orientations and interface structures. The results obtained could guide the development of high-efficiency and stable photoelectrodes for photoelectrochemical water splitting.

p型Cu2O是构建光电化学分解水制氢用光阴极中极具前景的材料，但其光腐蚀严重，限制了Cu2O基光电极的发展。由于光生载流子的快速导出与转移是抑制光腐蚀的本质因素，本项目提出基于晶体取向和界面结构的双重调控来实现光生载流子快速导出与转移的新思路，构建高效稳定的Cu2O基光电极。拟利用电化学沉积方法调控Cu2O薄膜的生长取向，制备沿着高导电取向择优生长的薄膜，促进光生载流子由体相快速输运至表面；在此基础上，分别在集流体/Cu2O和Cu2O/电解液两界面上构建有利于空穴和电子转移的欧姆接触和共晶格pn结，使得空穴和电子能从Cu2O表面分别有效转移至对电极和pn结的n型部分，实现光生载流子的有效转移，最大程度地抑制光腐蚀；并进一步在电极表面构筑析氢助催化剂，降低水分解反应势垒，提高反应效率。本项目将阐明基于晶体取向和界面结构的双重调控来促进光生载流子快速导出与转移的规律与机制，为发展高效稳定的光电

Cu2O是构建光电化学分解水制氢用光阴极中极具前景的材料，因光腐蚀问题而限制了Cu2O基光电极的发展。本项目提出基于晶体取向和界面结构的双重调控来实现光生载流子快速导出与转移的新思路，构建高效稳定的Cu2O基光电极。制备沿着高导电取向择优生长的薄膜，促进光生载流子由体相快速输运至表面；分别在集流体/Cu2O和Cu2O/电解液两界面上构建有利于空穴和电子转移的欧姆接触和共晶格pn结，实现光生载流子的有效转移；并进一步在电极表面构筑析氢助催化剂，提高反应效率。本项目在构筑高效稳定的Cu2O光电极方面取得了创新性研究成果，利用高功函数金属Pt和共格生长的ZnO分别修饰Cu2O（[111]取向择优生长）与FTO和电解液的界面，证实了晶体取向与双界面的协同调控可有效提升Cu2O光阴极的光电化学稳定性。基于本项目研究成果，作为第一作者已在国际核心刊物发表SCI论文2篇，申请发明专利2相，项目执行期间，培养毕业博士研究生1名。基本达到了项目预期研究目标。