Synthesis of Titanium Oxide Photocatalyst Supported on Spherical Porous Hydroxyapatite

抄録

We report the synthesis of a photocatalytic composite of spherical porous hydroxyapatite (sHAp) and TiO₂. sHAp was prepared by a wet method using simulated body fluid as a slurry and was then mixed with a TiO₂ sol to obtain the sHAp + TiO₂ composite. The TiO₂ content of sHAp + TiO₂ was ~7.8 wt. %. sHAp+TiO₂ showed photocatalytic activity that was more than ten times greater than that of TiO₂ even under irradiation with the low-intensity ultraviolet (UV) light of a fluorescent lamp. Mb decomposition of 58.2% was achieved under UV light with an intensity of 7.60 ×10² μW cm^-2 using the sHAp + TiO₂ composite, which is significantly higher than the 8.05% achieved using only TiO₂. Thus, the composite material showed higher activity than that of unsupported TiO₂. Furthermore, sHAp + TiO₂ could oxidize leucocrystal violet (LCV) to crystal violet (CV) even after being placed in the dark for 120 h. The positively charged holes are suggested to persist on TiO₂ because of the electron withdrawing effects of sHAp and can contribute to LCV oxidation. Thus, the photocatalytic activity of TiO₂ was improved by using sHAp as a support.