Investigating and correlating the photocatalytic activity of synthesised strontium titanate nanopowder with calcination temperature

In this study, SrTiO 3 nanoparticles were synthesised in high yield using a simple and low-cost method, followed by calcination. The effect of the calcination temperature in the range from 700 to 1100 °C on the morphology, phase structure, crystallite size, and photocatalytic activity of SrTiO 3 nanoparticles was investigated. Analysis of the morphology and structure of the synthesised samples revealed an increase in the average particle size from 70.4 to 361.72 nm as well as crystallite growth with increasing calcination temperature (from 800 to 1100 °C), likely due to the fusion of smaller crystallites into larger ones. A possible pathway for the growth mechanism of strontium titanate grains was also proposed. The SrTiO 3 sample calcined at 800 °C exhibited the highest methylene blue (MB) photodegradation efficiency, achieving 100% degradation within 30 min of irradiation. The pseudo-first-order reaction rate constant k for this sample was determined to be 0.156 min -1 , which is almost 1.8 and 14.19 times higher compared to those of commercial P25 and SrTiO 3 , respectively. The analysis indicated that the high photoactivity of this sample was due to its high crystallinity, relatively small particle size, and optimal light absorption, which enhanced the separation and transport of the photogenerated charges and increased the number of active sites, thereby positively affecting the photocatalytic properties. Additionally, the effects of the initial dye concentration and amount of photocatalyst loaded on the photodegradation efficiency were investigated. • SrTiO 3 nanoparticles were synthesized simply and cheaply • SrTiO 3 calcined at 800°C showed 100% methylene blue degradation in 30 mins