Fabrication of platy apatite nanocrystals loaded with TiO2 nanoparticles by two-step emulsion method and their photocatalytic activity

Nanometer-sized TiO2 island structure on the platy hydroxyapatite nanocrystals (HAp) has been accomplished by two-step emulsion process. At the first step, platy HAp nanocrystals, of which size was in the range of 70–200 nm after heat-treatment at 1078 K for 1 h, were prepared using the W/O emulsion system. Before the second step, HAp nanocrystals were immersed in NaH2PO4 solution for the formation of hydroxyl group on their surface. In the following, titanium tetraisopropoxide reacted with the hydroxyl group of HAp surface to form TiO2 nanoparticles on the surface of HAp nanocrystals, which were dispersed in the micrometer-sized methanol droplets of polyethylene cetylether–cyclohexane mixture (methanol/oil emulsion). The resulting hydroxyapatite nanocrystals loaded with TiO2 nanoparticles showed the high photocatalytic activity comparing to the commercial TiO2 catalyst.

Graphical abstractNanometer-sized TiO2 island structure with 10–20 nm in diameter was formed on the platy hydroxyapatite nanocrystal (HAp) in the range of 70–200 nm.Figure optionsDownload full-size imageDownload as PowerPoint slide