Premium
Understanding the synergistic effects, optical and electronic properties of ternary Fe/C/S‐doped TiO 2 anatase within the DFT + U approach
Author(s) -
Opoku Francis,
Govender Krishna Kuben,
van Sittert Cornelia Gertina Catharina Elizabeth,
Govender Penny Poomani
Publication year - 2018
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25505
Subject(s) - ternary operation , anatase , photocatalysis , band gap , doping , materials science , density functional theory , water splitting , absorption edge , visible spectrum , chemistry , optoelectronics , computational chemistry , catalysis , organic chemistry , computer science , programming language
Although TiO 2 is an efficient photocatalyst, its large band gap limits its photocatalytic activity only to the ultraviolet region. An experimentally synthesized ternary Fe/C/S‐doped TiO 2 anatase showed improved visible light photocatalytic activity. However, a theoretical study of the underlying mechanism of the enhanced photocatalytic activity and the interaction of ternary Fe/C/S‐doped TiO 2 has not yet been investigated. In this study, the defect formation energy, electronic structure and optical property of TiO 2 doped with Fe, C, and S are investigated in detail using the density functional theory + U method. The calculated band gap (3.21 eV) of TiO 2 anatase agree well with the experimental band gap (3.20 eV). The defect formation energy shows that the co‐ and ternary‐doped systems are thermodynamically favorable under oxygen‐rich condition. Compared to the undoped TiO 2 , the absorption edge of the mono‐, co‐, and ternary‐doped TiO 2 is significantly enhanced in the visible light region. We have shown that ternary doping with C, S, and Fe induces a clean band structure without any impurity states. Moreover, the ternary Fe/C/S‐doped TiO 2 exhibit an enhanced photocatalytic activity, a smaller band gap and negative formation energy compared to the mono‐ and co‐doped systems. Moreover, the band edges of Fe/C/S‐doped TiO 2 align well with the redox potentials of water, which shows that the ternary Fe/C/S‐doped TiO 2 is promising photocatalysts to split water into hydrogen and oxygen. These findings rationalize the available experimental results and can assist the design of TiO 2 ‐based photocatalyst materials.