Fig. 1

Characterization of the as-prepared ACP nanoparticles prepared using CaCl₂ as the calcium source and ATP as the organic phosphorus source in aqueous solution at 95 ℃ for 1 h. a–c SEM images. d–f TEM images. g XRD patterns. h FTIR spectra. i TG curves, and j nitrogen adsorption–desorption isotherms