S-1 Supporting Information Sacrificial Interlayer for Promoting Charge Transport in Hematite Photoanode Kai Zhang, †,§ Tianjiao Dong, †,‡,§ Guancai Xie, †,‡,§ Liming Guan, †,§ Beidou Guo, †,§ Qin Xiang, †,‡ Yawen Dai, †,‡ Liangqiu Tian, †,‡ Aisha Batool, †,‡ Saad Ullah Jan, †,‡ Rajender Boddula, †,‡ Akbar Ali Thebo, †,‡ and Jian Ru Gong *,† † Chinese Academy of Sciences (CAS) Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchy Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China ‡ University of Chinese Academy of Sciences, Beijing 100049, P. R. China Corresponding Author. * E-mail address: gongjr@nanoctr.cn (Prof. J. R. Gong) Author Contributions. § These authors contributed equally.