Surface treated TiO2 nanorod arrays for the improvement of water splitting

Water splitting is widely employed for the hydrogen production for its abundant sources of water and sunlight. The TiO₂ nanostructures are the most promising materials because of their properties of the non-toxicity and relatively low cost. Surface treatments with TiCl₄ solution and titanium butoxide solution are applied on the TiO₂ nanorod arrays respectively. On the surface of the TiO₂ nanorods, TiO₂ nanoparticles are prepared through hydrolysis of TiCl₄ and homogeneous phase of TiO₂ synthesized with assist of second hydrothermal synthesis in titanium butoxide, resulting in the increase of the surface area of the TiO₂. Comparing with that of the original TiO₂ nanorod arrays, the incident photon-to-electron conversion efficiency (IPCE) of the TiO₂–TiCl₄ and TiO₂–H₂O samples is greatly enhanced by 25% and 250% in the ultraviolet region, respectively. The obviously enhanced activity is due to the larger surface structure after treatments, which could contribute to the improved performance in the water splitting. These surface treatments provide an efficient way to regulate the properties of the TiO₂ nanorod arrays for their extensive applications in the solar device for the hydrogen production.