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 Sn 2+ and N co-doped TiO 2 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 Sn 2+ and N elements were co-doped into TiO 2 , 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 Sn 2+ and N co-doped TiO 2 extends to the visible light region. Compared with Sn 2+ -doped TiO 2 and N-TiO 2 , 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 Sn 2+ and N co-doping TiO 2 ( n (N)/ n (Ti) = 1) catalyst reached the maximum value of 0.37 mmol·h −1 ·g −1 under visible light, which is higher than that of N-doped TiO 2 and Sn 2+ -doped TiO 2 singly. This result is due to the wider visible light region-responsive ability of Sn 2+ and N co-doped into TiO 2 . Furthermore, mild hydrothermal methods will not make the Sn 2+ oxidized to Sn 4+ , 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 TiO 2 with high crystallinity, excellent performance and broad application prospects. Graphic abstract