Visible light photocatalytic performance of La-Fe co-doped SrTiO3 perovskite powder

Abstract

Using simple solid state reaction route, the La and Fe doped SrTiO3 nanoparticle have been successfully synthesized. The effects of different dopant concentrations (1, 2, 3, 4 and 5 wt %) on the characteristics of the as-prepared samples were systematically investigated using various techniques. X-ray diffraction (XRD) investigation exhibit the formation of the cubic perovskite structure of all samples. Field emission scanning electron microscopy (FESEM) images have been confirmed the uniformity and particle size reduction of the samples with increasing of doping elements. Also, the increase of surface area from 9.7 m2/g for pure SrTiO3 to 64.2 m2/g for 5 wt% La-Fe doped SrTiO3 validated by Brunauer-Emmett-Teller (BET) studies. The UV–vis diffuse reflectance spectra (DRS) demonstrate the blue-shift of absorption tail for doped samples as well as reduction of band gap energies (from 3.2 eV to 2.72 eV) with the increase of the doped element. Photoluminescence (PL) analysis of the synthesis nanoparticle display defective states and decline in PL intensity as a result of the doping materials effect in SrTiO3. The 150 min of irradiation time, 0.6 g/L of catalyst dosage, and 5 ppm of initial MO concentration have been obtained as the optimum photocatalyst operating conditions. Also, the photocatalytic investigation reveals the enhancement of degradation rate of Methyl Orange (MO) under visible irradiation for the doped sample. The perfect photocatalytic activity at 4 wt% of Fe-La-doped SrTiO3 nanoparticles is around 19 times higher than that of pure SrTiO3 (96% compare to 5%). In the end, the photocatalytic performance mechanisms are deeply explained.