Green synthesis and characterization of ANbO3 (A = Na, K) nanopowders fabricated using a biopolymer

Abstract

Lead-free sodium niobate (NaNbO3, NN) and potassium niobate (KNbO3, KN) nanopowders were successfully synthesized by a simple and green synthesis process in gelatin media. Gelatin, which is a biopolymer, was used as stabilizer. In order to determine the lowest calcination temperature needed to obtain pure NN and KN nanopowders, the produced gels were analyzed by thermogravometric analyzer (TGA). The produced gels were calcined at 500[Formula: see text]C and 600[Formula: see text]C. The structural and optical properties of the prepared powders were examined using X-ray diffraction (XRD) technique, transmission electron microscopy (TEM), and UV–Vis spectroscopy. The XRD results revealed that pure phase NN and KN nanopowders were formed at low temperature calcination of 500[Formula: see text]C and 600[Formula: see text]C, respectively. The Scherrer formula and size-strain plot (SSP) method were employed to estimate crystallite size and lattice strain of the samples. The TEM images show that the NN and KN samples calcined at 600[Formula: see text]C have cubic shape with an average particle size of 60.95 and 39.29 nm, respectively. The optical bandgap energy of the samples was calculated using UV–Vis diffused reflectance spectra of the samples and Kubelka–Munck relation.