Synthesis, Characterization, and Application of Zr,S Co-doped TiO₂as Visible-light Active Photocatalyst

Abstract

A series of Zr,S co-doped TiO 2 were synthesized by a modified sol-gel method and characterized by various spectroscopic and analytical techniques. The presence of sulfur caused a red-shift in the absorption band of TiO 2 . Co-doping of sulfur and zirconium (Zr-TiO 2 -S) improves the surface properties such as surface area, pore volume, and pore diameter and also enhances the thermal stability of the anatase phase. The Zr-TiO 2 -S systems are very effective visible-light active catalysts for the degradation of toluene. All reactions follow pseudo firstorder kinetics with the decomposition rate reaching as high as 77% within 4 h. The catalytic activity decreases in the following order: Zr-TiO 2 -S > TiO 2 -S > Zr-TiO 2 > TiO 2 P-25, demonstrating the synergic effect of codoping with zirconium and sulfur. When the comparison is made within the series of Zr-TiO 2 -S, the catalytic performance is found to be a function of Zr-contents as follows: 3 wt % Zr-TiO 2 -S > 0.5 wt % Zr-TiO 2 -S > 5 wt % Zr-TiO 2 -S > 1 wt % Zr-TiO 2 -S. Higher calcination temperature decreases the reactivity of Zr-TiO 2 -S.