Understanding the doping mechanism of Sn in TiO2 nanorods toward efficient photoelectrochemical performance

Doping metal ions into titanium dioxide (TiO2) is an effective strategy toward the goal of high-performance photoelectrochemical (PEC) water splitting. Understanding the doping mechanism is crucial for tailoring the intrinsic properties of doped TiO2. In this study, we synthesized tin (Sn)-doped TiO2 nanorods using a hydrothermal method and aim to understand the doping mechanism of Sn into TiO2 for enhancing its PEC performance. The experimental results based on the morphological and structural analysis confirm the success of Sn doping into TiO2 in which the dopant is homogeneously distributed in the structure of the nanorods. Density functional theory calculation combined with thermodynamic analysis provides clear evidence for the doping mechanism of Sn into TiO2 crystal lattice. These results indicate that Sn dopant enters the rutile TiO2 lattice as a substitute for Ti site and while the substituted Sn does not induce any localized state within the band gap of TiO2, it gives a significant amount of its valence electron to conduction, thereby helping to improve the photocatalytic activity. Compared with the TiO2 nanorods sample, the Sn-doped TiO2 nanorods sample shows highly efficient PEC performance, where its photocurrent density is significantly improved to 4.2 mA/cm(2) with a high photoconversion efficiency of 2.1%. Our results may afford a better understanding of the doping mechanism of Sn in TiO2 and thus suggest that Sn-doped TiO2 can serve as a potential photocatalyst material for a variety of solar energy-driven applications.

Automated summary

In this study, Sn-doped TiO2 nanorods were synthesized and the doping mechanism of Sn into TiO2 was investigated. The experimental results verified the successful doping of Sn into TiO2, and the theoretical calculations explained how Sn substitutes for Ti in the crystal lattice and enhances the photocatalytic performance. The improved PEC performance of Sn-doped TiO2 nanorods suggests their potential as photocatalyst materials for solar energy-driven applications.