Superior photoelectrochemical activity of self-assembled NiWO4-WO3 heteroepitaxy
Do Thi Hien1*, Nguyen Van Chien2, Le Thi Quynh2, Kai-An Tsai2, Chen Jhih Wei3, Chun-Lin Wu3, Yi-Chun Chen3, Yung-Jung Hsu2, Ying-Hao Chu1,2
1Institute of Physics, Academic Sinica, Taipei, Taiwan
2Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan
3Department of Physics, National Cheng Kung University, Tainan, Taiwan
* presenting author:Thi Hien Do,
This study reports the first successful growth of self-assembled NiWO4-WO3 heteroepitaxy using pulsed laser deposition and our exploration on its excellent performance in photocatalytic water splitting. The fabrication of self-assembled NiWO4-WO3 heteroepitaxy offers an effective approach to attain a significantly enhanced photoresponse. By using X-ray photoelectron spectroscopy, the energy band diagram of NiWO4-WO3 heterostructure reveals the effective charge separation at their interface by injecting photo-generated electrons from conduction band of WO3 to that of NiWO4 and holes from valance band of NiWO4 to that of WO3, resulting in a great improvement in photoelectrochemical activity of NiWO4-WO3 heterostruture. The self-assembled NiWO4-WO3 heteroepitaxy emerges as a potential photoelectrode for photocatalytic water splitting.

Keywords: self-assembled heteroepitaxy, epitaxial nickel tungstate, water splitting, photoelectrochemical, charge separation