Synthesis of mesoporous-assembled TiO2 nanocrystals by a modified urea-aided sol-gel process and their outstanding photocatalytic H2 production activity

Mesoporous-assembled TiO2 nanocrystals with very high photocatalytic H2 production activity were synthesized through a modified sol-gel process with the aid of urea as mesopore-directing agent, heat-treated under various calcination temperatures, and assessed for their photocatalytic H2 production activity via water splitting reaction. The resulting mesoporous-assembled TiO2 nanocrystals were systematically characterized by N2 adsorption–desorption analysis, surface area and pore size distribution analyses, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The experimental results showed that the photocatalytic H2 production activity of the synthesized mesoporous-assembled TiO2 nanocrystal calcined at 500 °C, which possessed very narrow pore size distribution, was extraordinarily higher than that of the commercially available P-25 TiO2 and ST-01 TiO2 powders.

► Urea was used as a mesopore-directing agent to synthesize mesoporous-assembled TiO2. ► The photocatalytic H2 production activity of the synthesized TiO2 depended on calcination temperature. ► The synthesized TiO2 gave higher photocatalytic H2 production activity than commercial TiO2 powders.