title: Fabrication of bidirectionally doped β-Bi2O3/TiO2-NTs with enhanced photocatalysis under visible light irradiation.
abstract: Stable β-Bi2O3/TiO2-NTs photocatalyst with excellent visible-light-activity is successfully prepared by bidirectional doping. Stake structure of the TiO2-NTs provides a larger specific surface area and makes the contact area between the TiO2-NTs and β-Bi2O3 much larger; The stake structure of TiO2-NTs not only leads to a firmer combination of TiO2-NTs and β-Bi2O3, but also makes them dope one another deeply. The modification of Bi species into TiO2-NTs can form Bi-O-Ti chemical absorption bonds, then a localized impurity level is generated within the band gap. Electrons can be excited and transferred from the Bi(3+) impurity level to the conduction band (CB) of TiO2, similar to narrowing the band-gap of TiO2-NTs, resulting in a red shift of the absorption edge and an enhancement in visible-light activity. During annealing, Bi atoms are partially replaced by Ti atoms. The lattice of β-Bi2O3 is compressed around the Ti impurity, making the lattice dislocate and distort. This dislocation and distortion leads to an increase in the β-Bi2O3 valance band (VB), from 2.02 to 2.28 eV. Accordingly, the weak oxidability of β-Bi2O3 is improved, and its photocatalytic ability is further enhanced. Moreover, this lattice dislocation and distortion changes the Bi-O distances, thus remarkably improving the stability of the β-Bi2O3/TiO2-NTs.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai, China.
authors.forename: Deyi
authors.initials: D
authors.lastname: Li
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yalei
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xuefei
authors.initials: X
authors.lastname: Zhou
authors.forename: Sujin
authors.initials: S
authors.lastname: Guo
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D002384:Catalysis; D008027:Light; D043942:Nanotubes; D010084:Oxidation-Reduction; D010782:Photolysis; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: C009495:titanium dioxide; C033301:bismuth oxide; D014025:Titanium; D001729:Bismuth