Hydroxyapatite/Anatase Photocatalytic Core–Shell Composite Prepared by Sol‒Gel Processing

Resumo

The conditions for preparing hydroxyapatite/anatase Ca₁₀(PO₄)₆(OH₎₂/TiO₂ nanocomposites with a core–shell structure by sol‒gel processing have been optimized. The photocatalytic activity of these nanocomposites is close to that of the commercial photocatalysts based on titanium dioxide (precursor Ti(OBut)₄ concentration 40 vol %, hydroxyapatite/TiO₂ sol ratio 1: 2, annealing temperature 500°C). The photocatalytic activity of hydroxyapatite/TiO₂ composites with different anatase contents has been estimated for the first time from the singlet oxygen yield. It is shown that the degree of modification of apatite particle surface affects significantly the structural characteristics of the hydroxyapatite/TiO₂ composite. An increase in the relative anatase content reduces the sizes of apatite crystallites and increases their specific surface.