Nanocrystalline CaSb2O5(OH)2 and Ca2Sb2O7: Controlled syntheses, electronic structures and photocatalytic activity

A facile one-pot pH-dependent hydrothermal method has been developed in the controlled syntheses of CaSb2O5(OH)2 and cubic Ca2Sb2O7 with large specific surface area. The as-obtained samples were characterized by X-ray diffraction (XRD), N2-sorption BET surface area, UV–vis diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX) and Fourier transformation infrared spectroscopy (FT-IR). The electronic structures of CaSb2O5(OH)2 and cubic Ca2Sb2O7 were determined by density functional theory (DFT) calculations. The photocatalytic performance of the as-prepared CaSb2O5(OH)2 and cubic Ca2Sb2O7 was evaluated by the degradation of methyl orange (MO) and gaseous benzene. It was found that CaSb2O5(OH)2 is more photocatalytic active than Ca2Sb2O7. A low crystal packing factor (PF) of CaSb2O5(OH)2 is probably responsible for its superior photocatalytic performance as compared to that of cubic Ca2Sb2O7.

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► pH-dependent controlled syntheses of CaSb2O5(OH)2 and cubic Ca2Sb2O7 with large surface area.
► CaSb2O5(OH)2 and Ca2Sb2O7 show photocatalytic activity for the degradation of MO and benzene.
► CaSb2O5(OH)2 is more photocatalytic active than Ca2Sb2O7 due to its lower crystal packing factor (PF).