shows the measures of specific areas of TiO2 in which various metal catalysts were added to pure TiO2 and 15 wt.%WO3. Compared to pure TiO2, TiO2 in 15 wt.%WO3 added with various metal catalysts showed greater BET specific area, pore diameter and total pore volume. This may be explained by the fact that the added WO3 and metal catalysts to TiO2 inhibited the growth of the particles and thus increased the specific area, which in turn increased the sensitivity.