Facile synthesis of lanthanum doped strontium manganite for photocatalytic decolourization of malachite green

Abstract

La0.15Sr0.85MnO3(LSMO) manganite was synthesised using most popular sol–gel auto combustion technique. The synthesized LSMO phase in the nano dimension has been verified by structural and TEM analyses. The different electrical plots of ac conductivity, real, imaginary impedances, Nyquist in the frequency range of 1 kHz to 1 MHz were also discussed. The present perovskite is introduced here as a suitable photocatalyst for the visible light spectrum with a band gap energy of 2.36 eV. This reveals that proper light harvestion capable of producing reactive oxidative radicals which are directly or indirectly responsible for decolourization of malachite green (MG). As the redox potential of H2O/OH. was are more positive than the VB potential of La0.15Sr0.85MnO3, the photogenerated holes (h+) are not able to react with H2O/OH– to produce OH.. From this it is suggested that super oxide (O2–.) radicals was the effective species for the photocatyalytic decolourization of MG. The variation in dye concentration was demonstrated as a function of illumination time. Nearly all of the MG-dyes are adsorbed on the catalyst surface after 90 min, which results in decolorization.