The Adatoms on Cu₂O Surface Tuning Electronic Structure for the Photocatalytic Application

Jui-Cheng Kao^1*, Yu-Chieh Lo¹, Peng-Jen Chen², Jyh-Pin Chou³

¹Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
²Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan
³Department of Physics, National Changhua University of Education, Changhua, Taiwan

* Presenter:Jui-Cheng Kao, email:zxww789987@gmail.com

The first-principles calculations based on the density functional theory (DFT) have applied to study the electronic structures of Cu₂O (100), (110), and (111) surfaces. However, for the photocatalytic experiments, the influence of impurity atoms to photocatalytic activity is still not clear. The energies of surface states are slight above the Fermi level for the (100) and (110) bare surfaces, and the copper-dominant state existing within the band gap for the (111) surface. In this work, the electronic band structures of the Cu₂O surfaces adsorbed by H, OH, Na, Cl, and Br atoms are investigated. The results indicate that the adsorbed H atoms largely lower the energies of the surface states in the (100) and (110) surfaces. On the other hand, the energies of the surface states are risen by the other adsorbed atoms. For the (111) surface, the OH and H adsorbed on the surface unsaturated copper and oxygen atoms, respectively, showing the surface states within the band gap are saturated. These results imply that the H or OH can extremely decrease the surface state energies and be the photocatalytic inactivity, which different from the other adsorbed atoms. Overall, the electronic band structures of the adsorbed surfaces can provide assistances for the design of photocatalytic experiments.

Keywords: DFT calculations, Cu₂O surface, band structure