Preparation of photocatalyst using diatom frustules by liquid phase deposition method.

We prepared a photocatalyst using diatom frustules by the liquid phase deposition (LPD) method. Purified native frustules were reacted with boric acid (H3BO3) and ammonium hexafluorotitanate ((NH4)2TiF6) in order to cover the frustule surface with a TiO2 film. Scanning electron microscopy (SEM) observation revealed that the nanoporous structures of the frustules and grown TiO2 layers were co-existent after the LPD treatment when the incubation period was 6 and 12 h. Furthermore, photocatalytic activity of the functionalized frustules was clearly proved by the decomposition of methylene blue (MB) molecules. When the incubation periods were 12 and 24 h, reasonable photocatalytic activity was obtained. The results suggested that higher photocatalytic activity was achieved without losing nanoporous structures when the frustules were treated for 12 h by the LPD method.