The effect of calcium and phosphorus base compounds on the characteristic and morphology of in situ synthesized hydroxyapatite-reduced graphene oxide nanocomposite

In this investigation, hydroxyapatite/reduced Graphene Oxide (HA/rGO) nanocomposite was synthesized from different methods of calcium and phosphate ions, calcium acetate-calcium glycerophosphate, and calcium nitrate-diammonium hydrogen phosphate. Scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), X-ray powder diffraction (XRD), and Fourier Transform Infrared Spectrometer (FTIR) were used to investigate surface morphology, chemical compositions, phase structures, and chemical structural composition of the powder, respectively. Raman spectroscopy was selected to analyze structural characteristics, which confirms the existence of reduced graphene oxide in the composite. The combination of calcium acetate and calcium glycerophosphate has been used to synthesize HA/rGO nanopowder, which has not been used in previous investigations. This work aims to evaluate the dissimilarities due to the use of diverse precursors of calcium and phosphate ions with the presence of various rGO concentrations, and the modifications in morphology and crystallinity of the HA/rGO composites. We found that, as the graphene concentration in HA/rGO nanocomposites increases, the Ca/P ratio increases due to increasing nucleation sites. Additionally, the interaction between HA and rGO was influenced by the calcium precursor, with calcium acetate-based powders showing stronger hydrogen bonding but increased defects and reduced crystallinity.