Tunable band gap of N-V co-doped Ca:TiO2-B (CaTi5O11) for visible-light photocatalysis

作者：Wang, Dengxing; Wang, Shuo; Li, Baihai; Zhang, Zhihua^*; Zhang, Qiuju^*

来源：International Journal of Hydrogen Energy, 2019, 44(10): 4716-4723.

DOI：10.1016/j.ijhydene.2018.12.223

• Water splitting
• Photocatalysis
• N-V co-doped
• Density functional theory (DFT)
• Design of perovskite CaTi5O11

Visible-light photocatalysis in layered perovskite CaTi5O11 is measured by band-gap tuning with co-doped anionic nitrogen (N) and cationic vanadium (V). The screening of hybrid density functional (HSE06) calculation reveals that strong Coulomb interaction between the dopants and other atoms makes N-V co-doping energetically favorable and effective for narrowing the band gap. More importantly, co-doping can eliminate the impurity states to reduce the electron-hole combination and improve the efficiencies of photocatalysis, since the mono-doped N or V ion produces impurity near the Fermi level. The impurity state captures the photoexcitation-generated carriers and accelerates the recombination process of the electron-hole pairs, thus suppressing their photocatalytic performance. The alignment of the band edge position with respect to the water oxidation/reduction potential indicates that N-V co-doped CaTi5O11 can act as a potential photocatalytic water catalyst. Co-doping is expected to be an effective way of improving the visible-light photocatalytic activity in layered perovskite due to the elimination of recombining the electron-hole pairs.

• 单位
  中国科学院宁波材料技术与工程研究所; 电子科技大学; 大连交通大学