Impact of Si and Zr addition on the surface defect and photocatalytic activity of the nanocrystalline TiO 2 synthesized by the solvothermal method

Abstract

In the present work, the effects of Si and Zr addition on the surface defect and photocatalytic activity of the solvothermal-derived TiO 2 were investigated. The metal-doped TiO 2 samples were prepared with the molar ratio Si/Ti and Zr/Ti ranging from 0.002 to 0.1 and were subjected to two different cooling temperatures (room temperature and 77 K) after calcination as a post-synthesis treatment. The presence of a small amount of metal dopant caused a slight change in the TiO 2 crystallite and BET surface area (ranging from 7.8 to 10.6 nm and corresponding surface area 95 to 159 m 2/g). The photocatalytic activity of TiO 2 did not depend solely on the surface area but rather affected by the concentration of Ti 3+ on the catalyst surface as shown by a linear ascending trend of the ethylene conversion and the amount of Ti 3+/surface area of the catalysts. It is noted that addition of Zr had more positive effect than Si and the effect of post-treatment on the photocatalytic activity of TiO 2 catalysts was more pronounced than the addition of metal dopants.