Mechanism of the substrate-dependent photocatalytic property of Cu2O heterojunctions
Riza Ariyani Nur Khasanah1*, Hui-Ching Lin1, Hsiang-Yun Ho2, Yen-Ping Peng2, Tsong-Shin Lim1, His-Lien Hsiao1, Chang-Ren Wang1, Min-Chieh Chuang3, Forest Shih-Sen Chien1
1Applied Physics, Tunghai University, Taichung, Taiwan
2Environmental Science, Tunghai University, Taichung, Taiwan
3Chemistry, Tunghai University, Taichung, Taiwan
* Presenter:Riza Ariyani Nur Khasanah,
The electrodeposited Cu2O on conductive Ti and FTO substrates behaves as a photocathode. To date, Cu2O electrodeposited on an n-type semiconductor such as TiO2 nanotube arrays (TNA), frequently used as a photoanode, demonstrates a better photocatalytic activity than that of TNA. The preference of Cu2O to be a photoanode or a photocathode remains unclear because no systematic study was done. In this work, the photocatalytic properties of Cu2O/TNA, Cu2O/Ti, and Cu2O/FTO were studied without bias. From the spectral response, Cu2O/TNA, Cu2O/Ti, and Cu2O/FTO exhibited UV−visible photocurrent with the onset at 590 nm wavelength, consistent with their absorption edge and Cu2O/TNA photoanode demonstrated the spectral response outperformed Cu2O/Ti and Cu2O/FTO photocathodes. The photoanodic/photocathodic properties of those junctions were depicted by their energy diagrams. From time-resolved photoluminescence, no effect of charge separation occurred at Cu2O/TNA junction. The improved photocatalytic properties of Cu2O/TNA were attributed to the UV−visible absorption of Cu2O.

Keywords: photocatalysis, spectral response, Cu2O, TiO2 nanotube array