Facile one-pot hydrothermal method to prepare Sn(II) and N co-doped TiO2 photocatalyst for water splitting under visible light irradiation

In this paper, a visible light-responsive Sn2+ and N co-doped TiO2 photocatalyst was prepared by facile one-pot hydrothermal method. All as-prepared samples were characterized in detail by a series of characterization approaches. The results showed that the Sn2+ and N elements were co-doped into TiO2, while the catalyst still maintains anatase crystal structure and gets irregular little nanocluster in diameter of 9-10 nm with higher specific surface area. The absorption edge of Sn2+ and N co-doped TiO2 extends to the visible light region. Compared with Sn2+-doped TiO2 and N-TiO2, the absorption edges have obvious red-shift of about 50 and 70 nm, respectively. The synergistic effect of O 2p-N 2p and O 2p-Sn 5s hybridization to form impurity levels is the main reason for the red-shift. The hydrogen production performance of the Sn2+ and N co-doping TiO2 (n(N)/n(Ti) = 1) catalyst reached the maximum value of 0.37 mmol center dot h(-1)center dot g(-1) under visible light, which is higher than that of N-doped TiO2 and Sn2+-doped TiO2 singly. This result is due to the wider visible light region-responsive ability of Sn2+ and N co-doped into TiO2. Furthermore, mild hydrothermal methods will not make the Sn2+ oxidized to Sn4+, which make the catalysts still maintain high photocatalytic performance. This work provides a simple and mild method for the preparation of dual-element co-doped TiO2 with high crystallinity, excellent performance and broad application prospects. Graphic abstract

Automated summary

In this study, a visible light-responsive Sn2+ and N co-doped TiO2 photocatalyst was prepared using a facile one-pot hydrothermal method. The co-doped catalyst showed extended absorption edge to visible light region and higher hydrogen production performance compared to singly doped TiO2. The synergistic effect of O 2p-N 2p and O 2p-Sn 5s hybridization is the main reason for the improved catalytic activity.