Effects of PVA content on the synthesis of LaFeO3 via sol-gel route

LaFeO3 were synthesized via a sol-gel route based on polyvinyl alcohol (PVA). Differential scanning calorimetry (DSC), Thermogravimetric (TG), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM) techniques were used to characterize precursors and derived oxide powders. The effect of the ratios of positively charged valences to hydroxyl groups of PVA (Mn+/-OH) on the formation of LaFeO3 was investigated. XRD analysis showed that single-phase and well-crystallized LaFeO3 was obtained from the Mn+/-OH = 4:1 molar ratio precursor at 700 °C. For the precursor with Mn+/-OH = 2:1, nanocrystalline LaFeO3 with average particle size of ∼50 nm was formed directly in the charring procedure. With increase of PVA content to Mn+/-OH = 1:1, phase pure LaFeO3 was obtained at 500 °C.