| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1487040 | Materials Research Bulletin | 2016 | 5 Pages |
•Crystalline porous TiO2 aggregate was synthesized by using a hydroxyapatite template.•Anatase-rutile transformation was suppressed by the addition of the hydroxyapatite.•The aggregate had higher photocatalytic activity than the commercial TiO2 powder.
Crystalline meso-/macroporous TiO2 aggregate was synthesized by using a hydroxyapatite template. The hydroxyapatite could be removed by treating it with hydrochloric acid even after it was heated at 800 °C. The aggregate included macropore with sizes of 1–5 μm in diameter and longer than 5 μm in length, penetrating into the aggregate, with walls that consisted of nanoparticles. Based on the results of N2-BET and X-ray diffraction measurements, decline in specific surface area and anatase-rutile phase transformation during heating were suppressed by the addition of the hydroxyapatite. That is, the aggregate had higher specific surface area and higher anatase phase ratio than the control sample obtained without using the hydroxyapatite. Photocatalytic activity evaluated by a photo-decomposition of methylene blue dye increased with increasing heating temperature. The aggregate heat-treated at 800 °C had three times higher photocatalytic activity and twenty times larger aggregate diameter than the commercial ST-01 TiO2 powder.
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