| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
Various applications, especially those for environmental, are developing for TiO_2 photocatalyst. For its application, optimization of the morphology and photocatalytic activity are the important. If it is possible to obtain a fibrous titanic, a wide range of applications are considered to be possible, because of its easiness in handling and low pressure loss. In this study, the synthesis and characterization of fibrous TiO_2 was investigated.
Homogeneous fibrous TiO_2 with 50 to 250 μm of width and a few to 10cm of length was prepared by drying the suspension of the monodispersed TiO_2 particles at 78〜100℃. The fiber width increased with increasing concentration of suspension, particle diameter, or with decreasing drying temperature. The fibers had a rectangular plate-like shape and TiO_2 particles were densely and homogeneously packed to form the fibers.
The effects of a heat treatment on crystallinity, crystal type, speck surface area and pore size of the fibers were investigated. The TiO_2 fiber heat-treated at 400℃ had a high specific surface area as 180m^2/g and had both of micropore (0.57nm) caused by infra-particle pore and homogeneous mesopore (30nm) caused by inter-particle pore. The crystal type maintains anatase after heating even at 1000℃ depending on preparation conditions.
The photocatalytic activity of the titanic fibers formed from TiO_2 sol (D=7nm) increased by heat-treatments between 400〜800℃ and showed such a very high activity as 98% of NOx decomposition. The crystallinity also affects the photocatalytic activity.
The TiO_2-SiO_2 fibers were developed by using TiO_2 sol (D=6nm) and SiO_2 sol (D=8〜11nm). The photocatalytic activity of titanic increased by the addition of SiO_2 with the adsorptive action, i.e., 76% of NOx decomposition for 0wt% of SiO_2 content fibers and 93% of NOx decomposition for 40wt% of SiO_2 content fibers, and the strength of TiO_2 fibers were also increased by feat-treatments and the addition of SiO_2.
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