Abstract
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•Copper-substituted hydroxyapatite nanocrystals (CuHAp) were successfully synthesized and characterized.•Copper was quantitatively incorporated into hydroxyapatite with a limited content up to about 15 at.%.•The evolution of HAp nanoparticles microstructure with copper content is clarified.•The CuHAp catalysts have been successfully tested in the discoloration of Naphthol Blue Black dye solutions.
Copper-substituted calcium in hydroxyapatite nanocrystals (CuHAp) were synthesized by co-precipitation method and characterized using various analyses. Structural and chemical characterizations indicate that copper was quantitatively incorporated into the HAp structure, replacing calcium up to 15 at.%. The presence of copper in the HAp structure affected clearly its crystallinity and reduced its crystallite sizes. Rietveld analysis showed a regular decrease of the CuHAp cell parameters a and c. Moreover, this substitution caused a shift in the infrared absorption bands and the nuclear magnetic resonance signals of phosphate groups and a decrease in the thermal stability. Morphological characterizations indicated that the prepared CuHAp consists of extremely thin needle-shaped nanocrystals with a greater aggregation, and confirmed the decrease in crystal size that was associated to the increasing in the surface area. The prepared CuHAp nanocrystals showed a high catalytic effect (up to 70%) in the discoloration of the Naphthol Blue Black solutions.