title: Fabrication of platy apatite nanocrystals loaded with TiO2 nanoparticles by two-step emulsion method and their photocatalytic activity.
abstract: Nanometer-sized TiO(2) 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 NaH(2)PO(4) 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 TiO(2) 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 TiO(2) nanoparticles showed the high photocatalytic activity comparing to the commercial TiO(2) catalyst.
authors.affiliation: Department of Applied Chemistry, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan. m-iwa@apch.kindai.ac.jp
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Yuki
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Seishiro
authors.initials: S
authors.lastname: Ito
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Furuzono
authors.forename: Won-Kyu
authors.initials: WK
authors.lastname: Park
mesh_terms: D001031:Apatites / Q000737:chemistry*; D002384:Catalysis; D003460:Crystallization; D003510:Cyclohexanes / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry; D004655:Emulsions; D000432:Methanol / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D009821:Oils / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry; D010316:Particle Size; D010777:Photochemistry; D020959:Polyethylene / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D001031:Apatites; D003510:Cyclohexanes; D004655:Emulsions; D009821:Oils; D009942:Organometallic Compounds; C009495:titanium dioxide; C506365:Cyclohexane; C102815:titanium isopropoxide; D020959:Polyethylene; D017886:Durapatite; D014025:Titanium; D000432:Methanol