Enhanced photocatalytic activity of α-Bi2O3 with high electron-hole mobility by codoping approach: A first-principles study.

To improve the photocatalytic activity of narrow-gap material Bi 2 O 3 , efforts need be made to lower the electron–hole recombination rate and widen the response range of visible light. Understanding the related mechanism is vital, which may lead to high electron-hole mobility and suitable band edge. In this paper we have studied the atomic and electronic structure of single metallic atom (Ag, Cu, Pb, Pd, Sn)-doped and nitrogen (N)-metal codoped Bi 2 O 3 with α phase by first principles calculations. The calculation results firstly show that new impurity states appeared in band gap of α -Bi 2 O 3 after single metal doping, especially for the doping of Cu, Ag and Pb, which showed shallow acceptor levels for α -Bi 2 O 3 . And the formation energy analysis indicates that Cu doped system was easier to be formed than other doped systems. All of those calculated properties are helpful to enhance the photocatalytic property of α -Bi 2 O 3 , which agrees well with experimental results. Interestingly, for anion atom N together with metallic atom (Ag, Cu, Pb, Pd, Sn) codoped α -Bi 2 O 3 systems, it is found that N-2p state had impact on the electronic structure. Holes were demonstrated to be more delocalized in (Cu + N) codoped α -Bi 2 O 3 system, which was responsible for high mobility of holes, then lowering the electron–hole recombination, and finally improving the photocatalytic performance of Bi 2 O 3 significantly. [ABSTRACT FROM AUTHOR]