Light-induced Water Splitting in Au/BiFeO₃ Heterostructure
Yen-Lin Huang1*, Wei-Sea Chang2, Nguyen Van Chien1, Yung-Jung Hsu1, Ying-Hao Chu1
1Materials Science and Engineering, National Chaio Tung University, Hsinchu, Taiwan
2School of Engineering, Monash University Malaysia, Bandar Sunway, Malaysia
* presenting author:Yen-Lin Huang,
Harvesting energy from sunlight has always been a splendid goal for human beings. To convert solar energy into chemical energy, semiconductor with suitable electronic band structure and band gap engineering play an indispensable role in water splitting and photocatalysis. Many transition metal oxides combined with noble metal have been reported as excellent candidates for water splitting and photocatalysis in the past decade. In this report, we present a novel approach, epitaxial thin film process, to understand the mechanism of water splitting and photocatalysis using multiferroics, BiFeO₃ and noble metal, Au, heterostructures. Through advanced thin film process, we have successfully controlled the crystalline orientations of BiFeO₃ thin film and Au nano particle. Under this circumstances, the efficiency in three different orientations: (100), (110), and (111) of BiFeO3 can be studied independently and exclude lots of factors which can not be controlled in other processes, such as, grain size, crystalline size, orientation, and ferroelectric polarization. Moreover, controlling the size of gold nano particles can induce surface plasmon and hence enhance the efficiency of water splitting under the visible light region. The present fabrication process will provide copious information and profound understanding of photocatalysis and water splitting based on polarization-induced surface potential difference, crystalline facets and surface plasmon effect. On a broader perspective, our work emphasizes the effects of hybrid noble metal and oxide systems and paves the way toward an environmentally friendly technology.

Keywords: water splitting, surface plasmon