Photo-Active K and Na Doped Strontium Ferrite by Co-Precipitation; Ph, Oxidative and Thermal Stabilities Characterisation

Abstract

The perovskite nanoparticles, Sr1-XMXFeO3(M=Na and K, x=0.1, 0.2) were prepared using metal precursors; Fe(NO3)2.9H2O and Sr(NO3)2 by co-precipitation method in the presence of sodium dodecylsulphate. The produced powder was annealed at 500°C, 700°C, and 800°C in a Muffle furnace. The obtained powders were characterised using the powder X-ray diffraction (PXRD) which indicated that the samples crystallised in a distorted hexagonal structure. The prominent peak in each of the perovskite sample, increased with increasing annealing temperature. Thermogravimetric analysis (TGA) of the samples showed a weight loss between the temperature range of 300–500°C due to K2O decomposition. The differential thermal analysis (DTA) showed the powders to possess endothermic activities at the positive derivative weight lost, with desorption and vapourisation up to 400°C. The oxidative and thermal stabilities determined at 500°C and above for both the TGA and DTA were reported in this work. Scanning electron microscopy (SEM) of the powdered nanoparticles showed the morphology of the particles starting from the nucleation stage, to formation and distribution. The photocatalytic activity of all powders were tested against methylene blue pollutant as a mordant dye, both in the presence and absence of hydrogen peroxide at pH=6.8. Powders at lower annealing temperatures were not very active but all powders at 800°C showed the highest degradation efficiency for the Na and K doped SrFeO3, this was also confirmed at the pH of 12 for K-doped nanaoparticle on the MB photodegradation.