A. Legrouri et al., INFLUENCE OF PREPARATION METHOD ON CATALYTIC PROPERTIES OF MIXED CALCIUM-COBALT, Journal of Materials Science, 31(9), 1996, pp. 2469-2473
Mixed calcium-cobalt orthophosphates of the formula Ca3-xCOx(PO4)(2),
with 0 less than or equal to x less than or equal to 1.1, were prepare
d by coprecipitation and solid-state reaction. Structural characteriza
tion showed that, in both cases, the solids obtained resulted from sub
stitution of some Ca2+ ions by Co2+ ions in the beta-Ca-3(PO4)2 struct
ure. The solubility limit of cobalt in this structure corresponded to
x = 0.31. The morphology of these compounds was investigated by surfac
e-area measurements and scanning electron microscopy. When tested in t
he 2-propanol decomposition reaction, the maximum activity in dehydrog
enation was obtained with the compound corresponding to cobalt maximum
solubility in beta-Ca-3(PO4)2 structure. Higher activities were obtai
ned for samples prepared by coprecipitation.