Electrochemical Properties of Hydroxyapatite Crystal Surfaces on Anatase Photocatalysts

Hydroxyapatite (HAp) was crystallized on anatase titanium dioxide (TiO2) photocatalytic crystals or their thin films using of a pseudo-body solution method, and electrochemical properties of the HAp-adhered anatase TiO2 photocatalytic surfaces were discussed. Decomposition rates of methylene blue were faster for the HAp-adhered anatase TiO2 photocatalysts, although specific surface areas were smaller than those for the commercial anatase TiO2 ones. Surface potential dispersions on the HAp-adhered anatase TiO2 thin films before and after an ultraviolet light irradiation were measured by an atomic force microscopy. Changes in the color of leucocrystalviolet mixed in the HAp-adhered anatase TiO2 photocatalysts or the commercial anatase TiO2 ones with experimental durations were compared. Movements of electrons from the anatase TiO2 photocatalytic surfaces to the HAp, crystals and oxidizing reactions on the HAp-adhered anatase TiO2 photocatalytic surfaces in the dark were discussed on the basis of these experimental results.