The structure, electronic, and optical properties of (Sm,N)-codoped anatase TiO2 photocatalyst: A density functional study

•There are some N 2p and Sm 4f states appearing in the band gap for doping TiO2.•The band gap of (Sm,N)-codoped anatase TiO2 has an obvious decline about 0.8 eV.•The synergistic effect of (Sm,N) codoping enhances photocatalytic activity of TiO2.•The experimental results were firstly explained with the electronic structure.

The geometrical, electronic, and optical properties of Sm-doped, N-doped, and (Sm,N)-codoped anatase TiO2 were successfully calculated and simulated using the spin-polarized density functional theory. The researches of geometrical structures show that (Sm,N) codoping leads to lattice distortion, which reduces the recombination of the photogenerated electron–hole pairs. Moreover, the calculated results indicate that the synergistic effects of (Sm,N) codoping can lead to an obvious band gap narrowing and a N 2p state appearing in the forbidden gap, which leads to a significant redshift of the optical absorption edge and enhances the photocatalytic activity of the (Sm,N)-codoped anatase TiO2.

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