Synopsis
Photocatalytic TiO
2 was coated on a stainless steel (SUS316L) substrate via a sol-gel method at a calcination temperature of 600°C. The sol-gel precursor (titanium isopropoxide) solution was modified by adding crystalline (anatase or rutile) TiO
2 particles to control the crystal phase of the TiO
2 coated on the substrate. The effect of the number of TiO
2 coatings was also evaluated. The TiO
2 coating was characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The photocatalytic activity was evaluated from the degradation of methylene blue solution on the TiO
2 coating after UV irradiation. The amount of bacteria adhered on the substrate was also evaluated. The TiO
2 coating comprising a binary phase (anatase/rutile weight ratio = 4.9/5.1) showed the highest photocatalytic activity, which improved after increasing the number of coatings. The amount of bacteria adhered on each TiO
2-coated substrate was not sig-nificantly different from that on the uncoated substrate.
Key words: photocatalytic activity; TiO2; anatase; rutile; sol-gel method
