Synthesis and characterization of bismuth-based hydroxyapatites doped with cerium

This study deals with the theoretical and experimental characterizations of Bi-based hydroxyapatites (HAp) doped with Ce. Five samples of Bi-based HAp (at a constant amount of 0.125 at.%) with the addition of the Ce in various amounts (0, 0.125, 0.25, 0.375, and 0.500 at. %) were synthesized by using the wet chemical method. The prepared samples were investigated experimentally by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transforms infrared (FTIR) spectroscopy, Raman spectroscopy, differential thermal analysis (DTA), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). All the samples were also modeled by using a density functional theory (DFT), and theoretical results were obtained. Both experimental and theoretical results showed that the lattice parameters and unit cell volume were significantly affected by Ce content. The calculated bandgap energies of the samples gradually decreased from 4.6308 eV to 4.5299 eV. The density of states (DOS) were also affected by the amount of Ce. It was found that the sample doped with 0.500 at. % Ce showed the best biocompatibility among all the as-synthesized samples. The linear absorption coefficient increased with increasing amounts of Ce, while this decreased with increasing photon energy. The density increases ranging from 3.1615 g cm-3 to 3.1772 g cm-3 with the increasing Ce content. Both crystallite size and crystallinity gradually reduced with the increasing amount of Ce. FTIR and Raman spectra confirm the formation of the HAp structure for all the samples.