Controlled fabrication of Sn/TiO2 nanorods for photoelectrochemical water splitting

In this work, we investigate the controlled fabrication of Sn-doped TiO2 nanorods (Sn/TiO2 NRs) for photoelectrochemical water splitting. Sn is incorporated into the rutile TiO2 nanorods with Sn/Ti molar ratios ranging from 0% to 3% by a simple solvothermal synthesis method. The obtained Sn/TiO2 NRs are single crystalline with a rutile structure. The concentration of Sn in the final nanorods can be well controlled by adjusting the molar ratio of the precursors. Photoelectrochemical experiments are conducted to explore the photocatalytic activity of Sn/TiO2 NRs with different doping levels. Under the illumination of solar simulator with the light intensity of 100 mW/cm2, our measurements reveal that the photocurrent increases with increasing doping level and reaches the maximum value of 1.01 mA/cm2 at -0.4 V versus Ag/AgCl, which corresponds to up to about 50% enhancement compared with the pristine TiO2 NRs. The Mott-Schottky plots indicate that incorporation of Sn into TiO2 nanorod can significantly increase the charge carrier density, leading to enhanced conductivity of the nanorod. Furthermore, we demonstrate that Sn/TiO2 NRs can be a promising candidate for photoanode in photoelectrochemical water splitting because of their excellent chemical stability.