Effect of KCl, LiCl, and KCl+LiCl flux on the physical characteristic and photoactivity were investigated in the sol-gel process of preparing titania particles. Flux materials has melting points over 500℃. At these temperatures, titania has phase transition from anatase to rutile. Silica was used to increase the thermal stability of titania to inhibit the phase transition. As silica was embedded in the matrix of titania it inhibited the phase transition of titania and made us achieve pure anatase crystallite only.
Flux added titania/silica mixed oxide had larger anatase phase crystallite size calculated by Scherrer formula and larger pore size, than that of non-flux silica/titania mixed oxide. Enhancement in photoactivity for decomposition of trichloroethylene was shown with flux used silica/titania mixed oxide than that of the silica/titania particles without flux. Photoactivity was highest when the crystallite size of anatase phase was 11∼14nm. The particles prepared with KCl flux showed the highest photoactivity than among the three fluxes. Effect of KCl is known to reduce the defect of titania which enhanced the photoactivity of titania on trichloroethylene decomposition.
