Incorporation of Cu and Mn ions into hydroxyapatite channels and deposition of complex metal oxide

Abstract

The Cu-and Mn-incorporated apatite-type phosphate, Ca10(PO4)6CuxMny(O,OH)2, was successfully synthesized by heating the hydroxyapatite under N2 at 900 °C after Cu- and Mn-nitrate aqueous solution loading with x = 0–0.2 and y = 0–0.2 onto it. In Ca10(PO4)6Cu0·2Mn0·2(O,OH)2, Cu occupies the apatite channel center site, and the Mn site shifts from the center. The deposition of Cu and Mn species was found to occur upon heating Cu0·2Mn0.2-Ca-HAp at 600–800 °C in air, accommodating the spinel-type complex metal oxide, (Cu, Mn)3O4 formation from the apatite channel. In addition, the CuO deposition from the Ca10(PO4)6Cu0·2(O,OH)2 apatite was observed for samples heated at 600–800 °C, whereas Mn3O4 was observed for the Ca10(PO4)6Mn0·2(O,OH)2 sample heated at 800 °C. These results suggest that the presence of Cu in the apatite channel facilitates the deposition of Mn species.