Glycine–nitrate combustion engineering of neodymium cobaltite nanocrystals

NdCoO 3 nanocrystals formed via glycine–nitrate combustion method followed by heat treatment has been systematically studied. Formation of NdCoO 3 nanocrystals with minimal size of 7–10 nm from X-ray amorphous combustion products has been elucidated to be a very rapid process, occurring at the temperature of 550–600 °C for 5–30 min. The comparison of the minimum sizes of NdCoO 3 crystallites obtained from the offered empirical relation d min = ℓ unit cell · N (where N is 7–12 and ℓ unit cell is elementary cell parameter) and the data determined on the basis of X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed good correlation. The existence of special nanoporous microstructure and spatial limitations prevent NdCoO 3 particle growth. The kinetic equation based on Avrami–Erofeev nucleation model was offered to be correlated well with experimental data of fractional conversion ( α ) versus isothermal time ( τ ). The apparent activation energy ( E a = (338 ± 32) kJ) of formation of NdCoO 3 nanocrystals from X-ray amorphous combustion products obtained in excess of oxidant followed by heat treatment at 550–600 °C was determined. Graphic abstract