To improve the photoelectrochemical activity of TiO₂ for hydrogen production through water splitting, the band edges of TiO₂ should be tailored to match with visible light absorption and the hydrogen or oxygen production levels. By analyzing the band structure of TiO₂ and the chemical potentials of the dopants, we propose that the band edges of TiO₂ can be modified by passivated codopants such as (Mo+C) to shift the valence band edge up significantly, while leaving the conduction band edge almost unchanged, thus satisfying the stringent requirements. The design principle for the band-edge modification should be applicable to other wide-band-gap semiconductors.

Yanqin Gai,¹ Jingbo Li,¹ Shu-Shen Li,¹ Jian-Bai Xia,¹ and Su-Huai Wei^2
1State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China
²National Renewable Energy Laboratory, Golden, Colorado 80401, USA

URL:	http://link.aps.org/doi/10.1103/PhysRevLett.102.036402