In this research, photocatalytic properties of La0.7Sr1.3CoO4 Ruddlesden-Popper oxide have been investigated on methyl orange (MO) dye degradation under UV irradiation for the first time. Nanopowders of La0.7Sr1.3CoO4 were synthesized by a modified sol-gel method. The synthesized powders were characterized using XRD analysis, FE-SEM and TEM imaging techniques, Raman and UV–Vis spectroscopy. The XRD pattern revealed that the synthesized powders crystalize in tetragonal structure with I4/mmm space group and the optical band gap was evaluated about 2.5 eV, using tauc equation. Photo-degradation of 20 mL of MO solution was studied for different amounts of La0.7Sr1.3CoO4 (0.025, 0.050 and 0.1 g), as the photocatalysts. Moreover, the effect of different amounts of hydrogen peroxide (H2O2), as an electron acceptor, on the catalytic reaction was also investigated. Our results showed that MO degradation efficiency over the optimal amount of La0.7Sr1.3CoO4 was about 94% under UV irradiation after 75 min. This efficiency and the rate of MO degradation was found to increase with the presence of H2O2, as an oxidant. These results suggest that La0.7Sr1.3CoO4 nanopowder can be considered as a good and promising photocatalyst for dye degradation.

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